<p>CHEMISTRY</p>
<p><strong><em>PRACTICAL</em></strong></p>
<p><strong><em>1989 – 2020</em></strong></p>
<ul>
<li><strong><em>PRACTICAL QUESTIONS</em></strong></li>
<li><strong><em>COORDINATED MARK SCHEMES</em></strong></li>
<li><strong><em>PREPARATION AND CONFIDENTIAL INSTRUCTIONS</em></strong></li>
</ul>
<h2>Table of Contents</h2>
<p><strong><em>LEAD NOTES QUANTITATIVE AND QUALITATIVE ANALYSIS</em></strong></p>
<p><strong><em>QUALITATIVE ANALYSIS</em></strong></p>
<p><strong><em>IDENTIFICATION OF IONS</em></strong></p>
<ul>
<li><em>Addition of Sodium hydroxide</em></li>
<li><em>Addition of aqueous ammonia</em></li>
<li><em>Addition of dilute hydrochloric acid or sodium chloride</em></li>
<li><em>Addition of dilute Sulphuric acid or Sodium sulphate</em></li>
<li><em>Flame test</em></li>
<li><em>Action of heat</em></li>
<li><em>Oxidising and Reducing agents</em></li>
</ul>
<p><strong>ALSO READ;<span style="color: #0000ff;"><a style="color: #0000ff;" href="https://educationnewshub.co.ke/chemistry-practicals-guide/"> CHEMISTRY PRACTICALS GUIDE</a></span></strong></p>
<h2>QUANTITATIVE ANALYSIS</h2>
<p><strong><em>SETTING TRENDS TABLE</em></strong></p>
<table>
<tbody>
<tr>
<td colspan="8" width="789"><strong><em>Year and Question No.( )</em></strong></td>
</tr>
<tr>
<td colspan="8" width="789"><strong><em>The mole: Formulae and chemical equations TESTED in all years EXCEPT 2002</em></strong></td>
</tr>
<tr>
<td rowspan="2" width="225"><strong><em>Ac</em></strong><strong><em>i</em></strong><strong><em>d</em></strong><strong><em>s</em></strong><strong><em>,</em></strong><strong><em> Bases and</em></strong></p>
<p><strong><em>salts</em></strong></td>
<td width="83"><strong><em>90 </em></strong><em>(c)</em></td>
<td width="90"><strong><em>06 </em></strong><em>(1)</em></td>
<td width="83"><strong><em>09 </em></strong><em>(1)</em></td>
<td width="75"> ;</td>
<td width="75"> ;</td>
<td width="83"> ;</td>
<td width="77"> ;</td>
</tr>
<tr>
<td width="83"> ;</td>
<td width="90"> ;</td>
<td width="83"> ;</td>
<td width="75"> ;</td>
<td width="75"> ;</td>
<td width="83"> ;</td>
<td width="77"> ;</td>
</tr>
<tr>
<td rowspan="2" width="225"><strong><em>Energy changes in chemical and physical</em></strong></p>
<p><strong><em>processes</em></strong></td>
<td width="83"><strong><em>89 </em></strong><em>(III)</em></td>
<td width="90"><strong><em>94</em></strong><em>(1)</em></td>
<td width="83"><strong><em>95</em></strong><em>(1)</em></td>
<td width="75"><strong><em>97</em></strong><em>(1)</em></td>
<td width="75"><strong><em>00 </em></strong><em>(2)</em></td>
<td width="83"><strong><em>01</em></strong><em>(III)</em></td>
<td width="77"><strong><em>03 </em></strong><em>(2)</em></td>
</tr>
<tr>
<td width="83"><strong><em>04 </em></strong><em>(1)</em></td>
<td width="90"><strong><em>05</em></strong><em>(1)</em></td>
<td width="83"><strong><em>07 </em></strong><em>(1)</em></td>
<td width="75"><strong><em>08 </em></strong><em>(1)</em></td>
<td width="75"><strong><em>10 </em></strong><em>(1)</em></td>
<td width="83"><em>13(1)</em></td>
<td width="77"> ;</td>
</tr>
<tr>
<td width="225"><strong><em>Reaction rates and</em></strong></p>
<p><strong><em>reversible reactions</em></strong></td>
<td width="83"><strong><em>92 </em></strong><em>(1)</em></td>
<td width="90"><strong><em>99 </em></strong><em>(1)</em></td>
<td width="83"><strong><em>02 </em></strong><em>(1)</em></td>
<td width="75"><em>12(1)</em></td>
<td width="75"> ;</td>
<td width="83"> ;</td>
<td width="77"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="165"><strong><em>Questions</em></strong></td>
<td width="158"><strong><em>Mark schemes</em></strong></td>
<td width="227"><strong><em>Practical Requirements</em></strong></td>
</tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td width="269"><em>Practical Experience 1989</em></td>
<td width="136"><em>15</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>113</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1990</em></td>
<td width="136"><em>17</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>114</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1991</em></td>
<td width="136"><em>&#8211;</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>&#8211;</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1992</em></td>
<td width="136"><em>20</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>115</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1993</em></td>
<td width="136"><em>23</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>116</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1994</em></td>
<td width="136"><em>25</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>117</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1995</em></td>
<td width="136"><em>28</em></td>
<td width="186"><em>75</em></td>
<td width="111"><em>118</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1996</em></td>
<td width="136"><em>32</em></td>
<td width="186"><em>77</em></td>
<td width="111"><em>118</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1997</em></td>
<td width="136"><em>35</em></td>
<td width="186"><em>80</em></td>
<td width="111"><em>119</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1998</em></td>
<td width="136"><em>38</em></td>
<td width="186"><em>82</em></td>
<td width="111"><em>120</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 1999</em></td>
<td width="136"><em>41</em></td>
<td width="186"><em>83</em></td>
<td width="111"><em>121</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2000</em></td>
<td width="136"><em>43</em></td>
<td width="186"><em>85</em></td>
<td width="111"><em>122</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2001</em></td>
<td width="136"><em>46</em></td>
<td width="186"><em>87</em></td>
<td width="111"><em>123</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2002</em></td>
<td width="136"><em>49</em></td>
<td width="186"><em>89</em></td>
<td width="111"><em>124</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2003</em></td>
<td width="136"><em>51</em></td>
<td width="186"><em>90</em></td>
<td width="111"><em>125</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2004</em></td>
<td width="136"><em>57</em></td>
<td width="186"><em>&#8211;</em></td>
<td width="111"><em>126</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2005</em></td>
<td width="136"><em>58</em></td>
<td width="186"><em>92</em></td>
<td width="111"><em>127</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2006</em></td>
<td width="136"><em>60</em></td>
<td width="186"><em>93</em></td>
<td width="111"><em>128</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2007</em></td>
<td width="136"><em>63</em></td>
<td width="186"><em>99</em></td>
<td width="111"><em>129</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2008</em></td>
<td width="136"><em>66</em></td>
<td width="186"><em>105</em></td>
<td width="111"><em>130</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2009</em></td>
<td width="136"><em>69</em></td>
<td width="186"><em>102</em></td>
<td width="111"><em>131</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2010</em></td>
<td width="136"><em>75</em></td>
<td width="186"><em>107</em></td>
<td width="111"><em>132</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2011</em></td>
<td width="136"><em>81</em></td>
<td width="186"><em>115</em></td>
<td width="111"><em>142</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2012</em></td>
<td width="136"><em>87</em></td>
<td width="186"><em>118</em></td>
<td width="111"><em>143</em></td>
</tr>
<tr>
<td width="269"><em>Practical Experience 2013</em></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em>Introduction</em></strong></td>
<td width="136"><em>87</em></td>
<td width="186"><em>125</em></td>
<td width="111"><em>144</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>The main aim of Chemistry Practical examination is to test a candidates ability to: a). Follow instructions</p>
<ul>
<li><em>Handle apparatus and chemicals</em></li>
<li><em>Make accurate observations and deductions/inferences</em></li>
</ul>
<p>This book contains 26 practical examinations from 1989 &#8211; 2013 as they appeared in during the respective examinations periods. The requirements and preparation procedures for each practical has been provided.</p>
<p>The teacher should give minimal assistance to candidates when carrying experiments to build confidence and enable them make their own observations and inferences. Confidence is only built with constant practice. Candidates are also advised to write the observations as they ‘observe’ during the practical but not the literature they have read from the books.</p>
<p>In experiments involving quantitative analysis the readings show slight variations from the ones given in the answer scheme and also from region to region. Therefore in the calculations and plotting of graphs, the teachers are required to use their school values. Teachers are advised to use the scheme as a guide not as the final correct answer.</p>
<p><strong><em>QUANTITATIVE AND QUALITATIVE ANALYSIS</em></strong></p>
<p>The chemistry practical mainly tests the candidates on two parts. Qualitative analysis and quantitative analysis. Students should be exposed to various types of experiments during teaching. Where it is not possible to carry out experiments individually, a well designed demonstration should be undertaken. Teachers should avoid theoretical teaching as this has been manifested many times during the marking of this paper.</p>
<p>Language used to communicate the observations and results must be checked after each practical experiment. Discussion of the results and clear explanations should be given after every experiment. Apparatus must be cleaned to avoid contamination and must be assembled correctly if accurate observations are to be obtained.</p>
<h1>Introduction to Quantitative Analysis</h1>
<p>Quantitative analysis in chemistry practical examination mainly involves the volumetric analysis. Volumetric analysis is a means of estimating quantities of certain substances (often acids or alkalis) by an analytical process which involves measurement of volumes of liquids using pipettes, burettes and measuring cylinders. Weighing is also involved. It involves the use of the following apparatus</p>
<ul>
<li><em>Thermometer</em></li>
<li><em>Stop-watch/stop-clock</em></li>
<li><em>Other common apparatus found in a laboratory</em></li>
</ul>
<p>In the K.C.S.E Chemistry practical examination this section requires the candidate to carry out an experiment, record and interpret the data. The interpretation involves calculations and drawing graphs after a candidate has collected the data.</p>
<p>A candidate who is not sure with the calculations after collecting the data is advised to record all his data in the table (s) provided and finally do the calculations. About half of the total marks awarded in this section is mainly from the recording of the data.</p>
<p>It is important for the candidate to spend sometime reading the instructions and the procedure to ensure that all the apparatus and reagents are present and the procedure is clear. After that, the candidate can start going through the procedure step by step and recording the data</p>
<p> ;</p>
<p>In the procedure the key words are normally written in bold letters so that the candidate does not make any mistake.</p>
<p> ;</p>
<p>The common areas in chemistry tested in this section of the practical examination are; a). Moles and molar solution</p>
<ul>
<li><em>Titration i). Acid-base titration</em></li>
</ul>
<p>ii). Redox titration iii). Back titration</p>
<ul>
<li><em>Solubility and drawing solubility curves</em></li>
<li><em>D</em><em>e</em><em>t</em><em>e</em><em>r</em><em>m</em><em>i</em><em>n</em><em>i</em><em>n</em><em>g</em> <em>m</em><em>e</em><em>l</em><em>t</em><em>i</em><em>n</em><em>g</em><em>,</em> <em>f</em><em>r</em><em>ee</em><em>z</em><em>i</em><em>n</em><em>g</em><em>,</em> <em>a</em><em>n</em><em>d</em> <em>boilin</em><em>g</em> <em>poin</em><em>t</em><em>s</em></li>
<li><em>M</em><em>o</em><em>l</em><em>a</em><em>r</em> <em>he</em><em>a</em><em>t</em><em>s</em> <em>o</em><em>f</em> <em>r</em><em>e</em><em>a</em><em>c</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>e</em><em>.</em><em>g</em><em>.</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>d</em><em>i</em><em>s</em><em>place</em><em>m</em><em>e</em><em>n</em><em>t</em><em>,</em> <em>p</em><em>r</em><em>e</em><em>c</em><em>i</em><em>pi</em><em>t</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,,</em> <em>n</em><em>e</em><em>u</em><em>t</em><em>r</em><em>a</em><em>l</em><em>i</em><em>z</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n </em><em>a</em><em>n</em><em>d</em> <em>H</em><em>e</em><em>ss</em><em>’</em><em>s</em> <em>l</em><em>a</em><em>w</em></li>
<li><em>Rates of reactions and reversible reactions</em></li>
</ul>
<p> ;</p>
<h3>Possible errors made in quantitative analysis</h3>
<ol>
<li><em>Errors made when weighing the substance by the Technician or teacher</em></li>
<li><em>C</em><em>o</em><em>n</em><em>t</em><em>a</em><em>m</em><em>i</em><em>n</em><em>a</em><em>t</em><em>e</em><em>d</em><em> solutions due to use of apparatus, which are not clean. All apparatus e.g. burettes, measuring cylinders, beakers etc should be rinsed thoroughly before using them and after use</em></li>
<li><em>Candidates not able to read the stop- watch or thermometers properly when taking measurement of time and temperature respectively</em></li>
<li><em>Candidates not able to identity the end – point accurately during titrations</em></li>
</ol>
<p> ;</p>
<h3>Interpretation of data and calculations</h3>
<p>To score maximum marks, candidates are required to be perfect in drawing of graphs The mole concept is important to all the calculations involved in the practical examination.</p>
<p> ;</p>
<p>As observed earlier (from the trends table) the topic on energy changes is not properly understood. Questions on energy changes are repeated yearly. More time should be allocated to its teaching and students allowed to carry out experiments on heat changes. Heats of displacement, solution are quite easy to determine. Students should be allowed to determine them. More examples on calculations involving energy changes should be given to students for practice.</p>
<h1>Introduction to Qualitative Analysis</h1>
<table>
<tbody>
<tr>
<td width="10">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>This involves the identification of various ions in a substance. The tests in this section have been kept as simple as possible to enable the learner understand he/she is doing. To avoid these complex reacts the scheme has been restricted to the detection of the following ions;</p>
<table>
<tbody>
<tr>
<td width="10">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>NH <sup>+</sup>, K<sup>+</sup>, NA<sup>+</sup>, LI<sup>+</sup>, Ca<sup>2+</sup>, Ba<sup>2+</sup>, Al<sup>3+</sup>, Zn<sup>2+</sup>, Fe<sup>2+</sup>, Fe<sup>+3,</sup></p>
<p>Pb<sup>2</sup><sup>+</sup>,Cu<sup>2</sup><sup>+,</sup> CO <sup>2-</sup>, HCO3-, SO<sup>2-</sup>3, NO <sup>&#8211;</sup>, Cl<sup>&#8211;</sup>, Br<sup>&#8211;</sup> and I<sup>&#8211;</sup>.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="10">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>This section also tests candidates on identification of organic compounds and their characteristics. When doing the practical examination. Work systematically through the experiments, in the order they are given, writing your observations and deductions as you go along.</p>
<p>If you are unable to make sense of a particular reaction, leave it after recording your observations and move on to the next test or experiment. Do not waste time. You should have time at the end to go over your work, correcting mistakes and checking for anything you think you have missed. Follow the instructions and the procedure carefully.</p>
<h3>How to make observations and deductions</h3>
<p>Observations are changes you see when you carry out a test or experiment. Observations are;</p>
<ul>
<li><em>Colour changes</em></li>
<li><em>Formation of precipitate</em></li>
<li><em>Ga</em><em>s</em><em>e</em><em>s</em> <em>e</em><em>v</em><em>o</em><em>l</em><em>v</em><em>e</em><em>d</em><em>,</em> <em>i</em><em>n</em><em>c</em><em>l</em><em>u</em><em>d</em><em>i</em><em>n</em><em>g</em> <em>c</em><em>o</em><em>l</em><em>o</em><em>u</em><em>r</em><em>,</em> <em>s</em><em>m</em><em>e</em><em>ll</em><em>. </em><em>i</em><em>v</em><em>)</em><em>.</em><em> Sound, heat or light produced</em></li>
</ul>
<p> ;</p>
<h3>Tests for gases</h3>
<p>Do not waste time testing for gases unless you know a gas is being produced or unless its indicated in the instructions that test for and identify any gas being produced.</p>
<p> ;</p>
<h3>Gases can be detected by:</h3>
<ul>
<li><em>Colour</em></li>
<li><em>Effervescence (bubbling of gas) iii). Smell</em></li>
</ul>
<p>iv). Effect on moist litmus papers</p>
<h3>Deductions/Inferences</h3>
<table>
<tbody>
<tr>
<td width="10">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>Deductions are something you can say about the unknown substances. This can be: i). Anions and cations present in the unknown substance (e.g. SO <sup>2-</sup>, or Fe<sup>2+</sup> ions)</p>
<ul>
<li><em>the substance is an oxidizing or reducing agent</em></li>
<li><em>the substance is saturated or unsaturated (incase of organic substances)</em></li>
</ul>
<p> ;</p>
<p>Deductions must be specific.</p>
<ul>
<li><em>A common mistake is to simply write; “Cu<sup>2+</sup>. You should write Cu<sup>2+</sup> present</em></li>
<li><em>Do not forget that even tests that show no precipitate formed often </em><em>have a</em></li>
</ul>
<table>
<tbody>
<tr>
<td width="10">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>deduction. For example; you might add Ba(NO3)2 solution to a solution of a substance and see no precipitate. From this you can deduce that there is no sulphate, SO <sup>2-</sup>, present (otherwise a white precipitate would be seen)</p>
<ul>
<li><em>Another common fault is to give the identity of gases as </em></li>
</ul>
<p>Your</p>
<p>deduction is what type of a substance has produced the gas. For example,</p>
<p> ;</p>
<p>if you add acid to a solid and observe carbon (iv) oxide then a carbonate is present.</p>
<ul>
<li><em>Deductions must be written as soon as you have recorded your </em></li>
<li><em>Do not leave all the deductions until you have completed all the If you do</em></li>
</ul>
<p>this, you may miss important observations and deductions in other tests, often need the deductions from earlier test to make sense of later tests.</p>
<p> ;</p>
<h3>Identification of cations (metallic ions)</h3>
<p>The two common reagents used in the identification of cations are: i). Sodium hydroxide solution</p>
<p>ii). Aqueous ammonia</p>
<p> ;</p>
<p>However, other reagents like dilute hydrochloric acid or an aqueous solution of soluble chloride e.g. sodium chloride and dilute sulphuric acid or an aqueous solution sulphate</p>
<p>e.g. sodium sulphate are use to identify some cations.</p>
<p> ;</p>
<p>In most cases candidates are required to prepare small quantities of solution in a boiling tube or test tube for the unknown substance. If the substance is being tested is insoluble in water, dilute hydrochloric acid is added to the substance. If the solids still will not dissolve it is probably a lead salt and dilute nitric acid must be used.</p>
<p> ;</p>
<p>For the identification of ions to be done the compound must be in aqueous form. The alkali is first added drop wise while the candidate records the observation and then in excess again and observation recorded.</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Addition of Sodium Hydroxide Solution to a Solution in a Test Tube</em></strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="195"><strong><em>Test</em></strong></td>
<td width="288"><strong><em>Observation</em></strong></td>
<td width="246"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td rowspan="4" width="195"><em>Add a few drops of NaOH solution drop wise until in excess</em></td>
<td width="288"><em>a). No precipitate formed</em></td>
<td width="246"><em>Zn<sup>2+</sup>, Al<sup>3</sup><sup>+</sup>, Pb<sup>2</sup><sup>+</sup>, Mg<sup>2</sup><sup>+</sup>, or Ca<sup>2</sup><sup>+</sup></em></p>
<p><em>absent.</em></td>
</tr>
<tr>
<td width="288"><em>b). White precipitate , insoluble in excess of</em></p>
<p><em>NaOH</em><em>(aq)</em></td>
<td width="246"><em>Ca<sup>2+</sup> or Mg<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>c). White precipitate,</em></p>
<p><em>soluble in excess NaOH </em><em>(aq)</em></p>
<p><em>forming a colourless solution.</em></td>
<td width="246"><em>Pb<sup>2</sup><sup>+</sup>,Al<sup>3+</sup> or Zn<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>d). Green precipitate which</em></p>
<p><em>turns brown on exposure to air.</em></td>
<td width="246"><em>Fe<sup>2+</sup> present</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="195"> ;</td>
<td width="288"><em>e). Brown precipitate</em></p>
<p><em>insoluble in excess NaOH</em><em>(aq)</em></td>
<td width="246"><em>Fe<sup>3+</sup> present</em></td>
</tr>
<tr>
<td width="195"> ;</td>
<td width="288"><em>f). A blue precipitate is formed</em></p>
<p><em>insoluble in excess NaOH</em></td>
<td width="246"><em>Cu<sup>2+</sup> ions present</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong><em>Addition of aqueous ammonia to a salt solution in a test tube</em></strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="195"><strong><em>Test</em></strong></td>
<td width="288"><strong><em>Observation</em></strong></td>
<td width="246"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td rowspan="6" width="195"><em>Add a few drops of NH</em><em>3(aq) solution until in excess</em></td>
<td width="288"><em>a). No white precipitate</em></p>
<p><em>formed</em></td>
<td width="246"><em>Ca<sup>2+</sup> present/ Na<sup>+</sup>, K<sup>+</sup>, NH <sup>+</sup></em></p>
<p><em>4</em></td>
</tr>
<tr>
<td width="288"><em>b). White precipitate ,</em></p>
<p><em>insoluble in excess of NH</em><em>3(aq)</em></td>
<td width="246"><em>Mg<sup>2+</sup>,Pb<sup>2</sup><sup>+</sup> or Al<sup>3+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>c). White precipitate,</em></p>
<p><em>soluble in excess NH</em><em>3(aq).</em></td>
<td width="246"><em>Zn<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>d). Green precipitate insoluble</em></p>
<p><em>in excess</em></td>
<td width="246"><em>Fe<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>e). Brown precipitate insoluble</em></p>
<p><em>in excess</em></td>
<td width="246"><em>Fe<sup>3+</sup> present</em></td>
</tr>
<tr>
<td width="288"><em>f). Pale blue precipitate; which dissolves to form a deep-blue</em></p>
<p><em>solution in excess NH</em><em>3(aq)</em></td>
<td width="246"><em>Cu<sup>2+</sup> present</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong><em>Addition of Dilute Hydrochloric Acid or Sodium Chloride Solution</em></strong></p>
<table>
<tbody>
<tr>
<td width="285"><strong><em>Test</em></strong></td>
<td width="198"><strong><em>Observation</em></strong></td>
<td width="245"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td rowspan="2" width="285"><em>Add a few drops or (a known volume) of dilute HCl or NaCl</em><em>(aq) to a solution in a test tube.</em></p>
<p><strong><em> </em></strong></p>
<p><em>‘’ ‘’ ‘’ ‘’ ‘’</em></td>
<td width="198"><em>a). White precipitate</em></p>
<p><em>formed</em></td>
<td width="245"><em>Pb<sup>2</sup><sup>+,</sup> Ag<sup>2+</sup> ionspresent.</em></td>
</tr>
<tr>
<td width="198"><em>b). No white</em></p>
<p><em>precipitate formed</em></td>
<td width="245"><em>Pb<sup>2+</sup> and Ag<sup>+</sup> ions absent</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong><em>Addition of Dilute H</em></strong><strong><em>2SO</em></strong><strong><em>4 acid or Sodium Sulphate Solution</em></strong></p>
<table>
<tbody>
<tr>
<td width="285"><em>Test</em></td>
<td width="198"><em>Observation</em></td>
<td width="245"><em>Inference</em></td>
</tr>
<tr>
<td rowspan="2" width="285"><em>Add a few drops or (known volume) of dilute H</em><em>2SO</em><em>4 or NaSO</em><em>4 to a solution in a test tube.</em></p>
<p><strong><em> </em></strong></p>
<p><em>‘’ ‘’ ‘’ ‘’ ‘’</em></td>
<td width="198"><em>a). White precipitate</em></p>
<p><em>formed</em></td>
<td width="245"><em>Ca<sup>2+</sup>, Pb<sup>2</sup><sup>+</sup> or Ba<sup>2+</sup> present.</em></td>
</tr>
<tr>
<td width="198"><em>b). No white precipitate formed</em></td>
<td width="245"><em>Ba<sup>2+</sup>, Pb<sup>2</sup><sup>+</sup>,or Ca<sup>2+</sup>, absent</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<h3>Identification of Cations Using the Flame Test</h3>
<p>The presence of some metallic ions can be identified by heating the substance in a flame using a platinum wire or a glass rod</p>
<p> ;</p>
<h3>The Bunsen burner flame should be non-luminous for correct observation to be made</h3>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="285"><em>Test</em></td>
<td width="198"><em>Observation</em></td>
<td width="245"><em>Inference</em></td>
</tr>
<tr>
<td width="285"><em>Dip a clean platinum wire or a</em></td>
<td width="198"><em>a). Lilac or purple</em></td>
<td width="245"><em>K<sup>+</sup> present.</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="285"><em>glass rod into a solution of salt</em></td>
<td width="198"><em>/orange flame</em></td>
<td width="245"> ;</td>
</tr>
<tr>
<td rowspan="4" width="285"> ;</td>
<td width="198"><em>b). Golden yellow</em></p>
<p><em>flame</em></td>
<td width="245"><em>Na<sup>+</sup> present</em></td>
</tr>
<tr>
<td width="198"><em>c). Crimson flame</em></td>
<td width="245"><em>Li<sup>+</sup> present</em></td>
</tr>
<tr>
<td width="198"><em>d).Brick-red flame</em></td>
<td width="245"><em>Ca<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="198"><em>e).Green-blue flame</em></td>
<td width="245"><em>Cu<sup>2+</sup> present</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong><em>Identification of Anions</em></strong></p>
<p>The substances to be identified must be in aqueous form before the reagents are added The anions are commonly identified by the use of dilute acids e.g. HCl acid. Precipitation reactions with reagents listed in the table below are used as confirmatory tests.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="285"><strong><em>Test</em></strong></td>
<td width="270"><strong><em>Observation</em></strong></td>
<td width="174"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td width="285"><em>1). Add dilute acid e.g. HCl to a</em></p>
<p><em>solution in a test tube</em></td>
<td width="270"><em>Effervescence /bubbles of a</em></p>
<p><em>gas are produced.</em></td>
<td width="174"><em>CO <sup>2-</sup> or HCO <sup>&#8211;</sup> </em><em>3</em><em> </em><em>3</em></p>
<p><em>SO<sup>2-</sup></em><em>3 present</em></td>
</tr>
<tr>
<td width="285"><em>2). Add barium Chloride or Barium nitrate solution to a solution in a test tube followed</em></p>
<p><em>by dilute HCl acid</em></td>
<td width="270"><em>White precipitate formed which is insoluble in dilute HCl acid</em></td>
<td width="174"><em>SO <sup>2-</sup> present</em></p>
<p><em>4</em></td>
</tr>
<tr>
<td width="285"><em>3). Add barium Chloride or Barium nitrate solution to a solution in a test tube followed by dilute nitric acid or dil. HCl respectively</em></td>
<td width="270"><em>White precipitate is formed which dissolves on the addition of the acid</em></td>
<td width="174"><em>SO <sup>2-</sup> or CO <sup>2-</sup></em></p>
<p><em>3 3</em></p>
<p><em>present</em></td>
</tr>
<tr>
<td rowspan="4" width="285"><em>4).Acid lead (II) nitrate to a solution in a test tube followed by dilute HNO</em><em>3 acid</em></td>
<td width="270"><em>White precipitate formed</em></p>
<p><em>which dissolved on boiling</em></td>
<td width="174"><em>Cl<sup>&#8211;</sup> present</em></td>
</tr>
<tr>
<td width="270"><em>b).White precipitate insoluble</em></p>
<p><em>on boiling</em></td>
<td width="174"><em>SO <sup>2-</sup> or CO <sup>-2</sup></em></p>
<p><em>4 3</em></p>
<p><em>present</em></td>
</tr>
<tr>
<td width="270"><em>c).Pale cream precipitate</em></p>
<p><em>formed.</em></td>
<td width="174"><em>Br<sup>&#8211;</sup> present</em></td>
</tr>
<tr>
<td width="270"><em>d).Yellow precipitate formed</em></td>
<td width="174"><em>I<sup>&#8211;</sup> present</em></td>
</tr>
<tr>
<td width="285"><em>5).Add a small quantity of cold, iron (II) sulphate solution. Gently</em></p>
<p><em>pour concentrated H</em><em>2SO</em><em>4 acid down the side of the tube.</em></td>
<td width="270"><em>A brown ring forms in the junction of the two layers</em></td>
<td width="174"><em>NO <sup>&#8211;</sup> present</em></p>
<p><em>3</em></td>
</tr>
<tr>
<td width="285"><em>6). Add dilute acid to a substance in test tube Test with acidified KMnO</em><em>4</em></p>
<p><em>solution or acidified K</em><em>2Cr</em><em>2O</em><em>7</em></td>
<td width="270"><em>A gas with a smell of rotten egg evolved</em></p>
<p><em>Gas blackens the lead ethanoate paper or lead (II) nitrate solution.</em></td>
<td width="174"><em>S<sup>2-</sup> present</em></td>
</tr>
<tr>
<td width="285"><em>7). Add dilute acid to a substance in test tube Test with acidified KMnO</em><em>4</em></p>
<p><em>solution or acidified K</em><em>2 Cr</em><em>2 O</em><em>7</em></td>
<td width="270"><em>Effervescence (bubbles of a colourless gas</em></p>
<p><em>Pungent smell</em></p>
<p><em>KMnO</em><em>4 turn from purple to colourless</em></td>
<td width="174"><em>SO <sup>2-</sup> present</em></p>
<p><em>3</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="285"> ;</td>
<td width="270"><em>K</em><em>2Cr</em><em>2O</em><em>7 turn from orange to green</em></td>
<td width="174"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<h3>Action of Heat</h3>
<p>When heating solid substances always makes sure that the test-tube is clean and dry.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="237"><strong><em>Test</em></strong></td>
<td width="246"><strong><em>Observation</em></strong></td>
<td width="246"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td width="237"><em>Heat a small amounts of the solid in a clean and dry test tube and test for any gas or gases evolved</em></td>
<td width="246"><em>a). Colourless liquid formed on cooler part or upper part of test tuber OR vapour condenses to a colourless</em></p>
<p><em>liquid</em></td>
<td width="246"><em>Hydrated salt or a hydrogen</em></p>
<p><em>-carbonate or hydroxide</em></td>
</tr>
<tr>
<td rowspan="5" width="237"> ;</td>
<td width="246"><em>b). Colourless gas which gives a white precipitate</em></p>
<p><em>with lime water</em></td>
<td width="246"><em>CO <sup>2-</sup> /HCO<sup>&#8211;</sup></em><em>3 present</em></p>
<p><em>3</em></td>
</tr>
<tr>
<td width="246"><em>c).Colourless gas that</em></p>
<p><em>relights glowing splint</em></td>
<td width="246"><em>Nitrate of potassium or</em></p>
<p><em>sodium</em></td>
</tr>
<tr>
<td width="246"><em>d).Pungent smell; dark brown gas which turns</em></p>
<p><em>moist blue litmus red</em></td>
<td width="246"><em>NO <sup>&#8211;</sup> present (except those</em></p>
<p><em>3</em></p>
<p><em>of Na and K)</em></td>
</tr>
<tr>
<td width="246"><em>e). Pungent smelling gas</em></p>
<p><em>which turns red litmus blue.</em></td>
<td width="246"><em>NH <sup>+</sup> present</em></p>
<p><em>4</em></td>
</tr>
<tr>
<td width="246"><em>f).Sublimation</em></td>
<td width="246"><em>Possibly NH <sup>+</sup></em></p>
<p><em>4</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<h3>Test for oxidizing and reducing agents</h3>
<p>The usual method of testing for an oxidizing agent is to mix it with a substance which is easily oxidized (i.e. a reducing agent) and which gives a visible change when the reaction takes place. Similarly, a suspected reducing agent is added to an oxidizing agent which undergoes a visible change when reduced.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="237"><strong><em>Test</em></strong></td>
<td width="246"><strong><em>Observation</em></strong></td>
<td width="297"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td width="237"><em>1. <u>Oxidising agents</u></em></p>
<p><em>a). Test with moist starch- potassium iodide paper</em></td>
<td width="246"><em>Papers turns blue-black</em></td>
<td width="297"><em>I<sup>&#8211;</sup>ions are oxidized to I</em><em>2: which then react with starch</em></td>
</tr>
<tr>
<td width="237"><em>b). Warm with Conc. HCl</em></td>
<td width="246"><em>Cl</em><em>2(smell, bleaches moist litmus paper</em></td>
<td width="297"><em>Cl<sup>&#8211;</sup> Oxidised to Cl</em><em>2</em></td>
</tr>
<tr>
<td width="237"><em>2. Reducing agents a).Add acidified KMnO</em><em>4</em></p>
<p><em>solution</em></td>
<td width="246"><em>Purple solution is decolorized</em></td>
<td width="297"><em>Purple MnO <sup>&#8211;</sup></em><em>(aq) reduced to</em></p>
<p><em>4</em></p>
<p><em>colourless Mn<sup>2+</sup></em><em>(aq) ions</em></td>
</tr>
<tr>
<td width="237"><em>b). add acidified</em></p>
<p><em>K</em><em>2Cr</em><em>2 O</em><em>7(aq)</em></td>
<td width="246"><em>Orange solution turns green</em></td>
<td width="297"><em>Cr</em><em>2 O <sup>2-</sup> ions are reduced to green</em></p>
<p><em>7</em></p>
<p><em>Cr</em><em>3+</em><em>(aq) ions</em></td>
</tr>
<tr>
<td width="237"><em>c). Add a solution of an</em></p>
<p><em>Iron(III)salt</em></td>
<td width="246"><em>Yellow solution turns pale</em></p>
<p><em>Green</em></td>
<td width="297"><em>Fe<sup>3+</sup></em><em>(aq) ions reduced to Fe<sup>2+</sup>ions</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="237"><strong><em>Test</em></strong></td>
<td width="246"><strong><em>Observation</em></strong></td>
<td width="305"><strong><em>Inference</em></strong></td>
</tr>
<tr>
<td width="237"><em>Add acidified KMnO</em><em>4 solution to a solution in a</em></p>
<p><em>test-tube</em></td>
<td width="246"><em>The purple KMnO</em><em>4 turns colourless or decolourised</em></td>
<td width="305"><em>SO <sup>2-</sup> ions present OR unsaturated</em></p>
<p><em>3</em></p>
<p><em>organic compound OR a reducing agent</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="237"><em>Add acidified K</em><em>2Cr</em><em>2O</em><em>7 solution to a solution in a</em></p>
<p><em>test tube</em></td>
<td width="246"><em>It turns green or colour changes from orange to</em></p>
<p><em>green</em></td>
<td width="305"><em>2-</em></p>
<p><em>SO</em><em>3 ions present OR unsaturated</em></p>
<p><em>organic compound OR a reducing agent</em></td>
</tr>
<tr>
<td width="237"><em>Add bromine water to a solution in a test tube</em></td>
<td width="246"><em>It is decolourised or turns colourless</em></td>
<td width="305"><em>SO <sup>2-</sup> ions present OR unsaturated</em></p>
<p><em>3</em></p>
<p><em>Organic compound OR a reducing agent</em></td>
</tr>
<tr>
<td width="237"><em>Add chlorine water to a</em></p>
<p><em>solution in a test tube.</em></td>
<td width="246"><em>Brown solution/yellow</em></p>
<p><em>solution</em></td>
<td width="305"><em>Br<sup>&#8211;</sup> of I<sup>&#8211;</sup> present</em></td>
</tr>
<tr>
<td width="237"><em>Add bromine water to a</em></p>
<p><em>solution in a test tube</em></td>
<td width="246"><em>Brown solution/black</em></p>
<p><em>precipitate</em></td>
<td width="305"><em>I<sup>&#8211;</sup> present</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p>Candidates are advised that MARKS are only earned if observation is correct and the scientific language used to describe that observation. It should be known that if the observation is wrong or correct scientific language is not used, then all the marks will be lost.</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER &#8211; NOVEMBER 1989</h2>
<h3>1. You are provided with;</h3>
<ul>
<li><em>A</em><em>q</em><em>u</em><em>e</em><em>o</em><em>u</em><em>s</em><em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>,</em><em> </em><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><strong><em>W</em></strong><em>9</em> <em>i</em><em>n</em><em> </em><em>a</em><em> </em><em>bu</em><em>r</em><em>e</em><em>tt</em><em>e</em><em>.</em></li>
<li><em>Solution sodium <strong>W</strong></em><em>11 </em><em>containing 3g of a dibasic acid H</em><em>2</em><em>CO</em><em>4</em><strong><em>.</em></strong><em>2H</em><em>2</em><em>O </em><em>per litre</em></li>
<li><em>Aqueous sodium hydroxide, solution <strong>W</strong></em><em>12</em><em>.</em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>A pair of scissors or a sharp blade</em></li>
</ul>
<p> ;</p>
<h3>You are required to;</h3>
<p><strong> </strong></p>
<ul>
<li><em>Standardize the sodium hydroxide solution <strong>W</strong></em><em>11</em></li>
<li><em>Use the standardized solution <strong>W</strong></em><em>11 </em><em>to determine the concentration of <strong>W</strong></em><em>9</em></li>
</ul>
<p> ;</p>
<p>React the hydrochloric acid solution <strong>W</strong>9 with metal <strong>M </strong>and determine the mass per unit length of metal <strong>M</strong>.</p>
<p> ;</p>
<h3>Procedure</h3>
<p><strong> </strong></p>
<p><strong>I </strong>Fill a burette with solution <strong>W</strong>11, pipette 25.0cm<sup>3</sup> of solution <strong>W</strong>12 into a conical flask. Titrate using phenolphthalein indicator. Record your results in Table A below;</p>
<p> ;</p>
<h3>Table A.</h3>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="263"> ;</td>
<td width="165"><em>1</em><em>st</em></td>
<td width="165"><em>2</em><em>nd</em></td>
<td width="137"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="263"><em>Final Burette Reading</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Initial Burette Reading</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks)</p>
<p> ;</p>
<ol>
<li><em>Average volume of solution <strong>W</strong></em><em>11 </em><em>used (1 mark)</em></li>
<li><em>Calculate the concentration of the dibasic solution W</em><em>11 </em><em>in mol<sup>-1</sup></em></li>
</ol>
<p>(C=12, H=1, O=16) (1 mark)</p>
<ul>
<li><em>Calculate the concentration of the sodium hydroxide solution <strong>W</strong></em><em>12 </em><em>in moll<sup>-1</sup></em></li>
</ul>
<p>(2</p>
<p>marks)</p>
<p> ;</p>
<ol start="10">
<li><em>Using a 100cm<sup>3</sup> measuring cylinder measure 90cm<sup>3</sup> of distilled water and place it into a 250cm<sup>3</sup> beaker then add 10cm<sup>3</sup> of solution <strong>W</strong></em><em>9 </em><em>(<strong>W</strong></em><em>9 </em><em>is supplied in a burette). </em><em>Mix the solution well and label it <strong>W</strong></em><em>10</em><em>.</em></li>
</ol>
<p> ;</p>
<p>Fill a burette with solution W10, pipette 25.0cm<sup>3</sup> of solution W12 into a conical flask. Titrate using phenolphthalein indicator. Record your results in Table B below.</p>
<h3>Table B.</h3>
<table>
<tbody>
<tr>
<td width="263"> ;</td>
<td width="165"><em>1</em><em>st</em></td>
<td width="165"><em>2</em><em>nd</em></td>
<td width="137"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="263"><em>Final Burette Reading</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Initial Burette Reading</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks)</p>
<ul>
<li><em>Average volume of solution W</em><em>10 </em><em> (1 mark)</em></li>
<li><em>Calculate the concentration of the diluted hydrochloric acid solution W</em><em>10 </em><em>in </em><em>mol l</em><em>-1</em><em>. </em><em>(2 marks)</em></li>
<li><em>Determine the concentration of the original hydrochloric acid solution W9 in mol l<sup>-1</sup> </em><em>(1 mark)</em></li>
</ul>
<ul>
<li><em>Cut three pieces each of length 2cm from the metal <strong>M </strong> From the burette </em><em>containing <strong>W</strong></em><em>9 </em><em>measure 10cm<sup>3</sup> of <strong>W</strong></em><em>9 </em><em>into a boiling tube. Wrap the boiling tube </em><em>with tissue paper. Measure the temperature of this solution and record it in <strong>Table </strong></em><strong><em>C </em></strong><em>below. Place one of the 2cm pieces of metal <strong>M </strong>into the hydrochloric solution <strong>W9 </strong>in the boiling tube and measure the temperature. Record the highest temperature in table C below. Repeat this procedure using the other two, 2cm, pieces of M.</em></li>
</ul>
<p> ;</p>
<h3>Table C.</h3>
<table>
<tbody>
<tr>
<td width="263"> ;</td>
<td width="165"><em>1</em><em>st</em></td>
<td width="165"><em>2</em><em>nd</em></td>
<td width="137"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="263"><em>Piece of metal M</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Highest temperature</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="263"><em>Initial temperature</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="263"><em>Change in temperature, âT</em></td>
<td width="165"> ;</td>
<td width="165"> ;</td>
<td width="137"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks)</p>
<p> ;</p>
<ul>
<li><em>Average change in temperature âT……………….<sup>0</sup>C </em><em>(1 mark)</em></li>
<li><em>Calculate the heat of the reaction between metal <strong>M </strong>and hydrochloric acid </em><em>using the expression below; heat of reaction = 42 x âT Joules (1 mark)</em></li>
<li><em>Given that the heat of the reaction is 440Kj per mole of <strong>M</strong>. Calculate the </em><em>number</em> <em>of moles of <strong>M </strong>used in this (2 marks)</em></li>
<li><em>Calculate the mass per unit length of metal M (M=24). </em><em>(2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>(10 Marks). You are provided with a solid Carry out the tests in Table D below </em><em>on Y. Record your observations and deductions in the table. Identify any gas</em><em> evolved.</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="43"> ;</td>
<td width="253"> ;</td>
<td width="195"><em>Observation</em></td>
<td width="189"><em>Deduction</em></td>
</tr>
<tr>
<td width="43"><em>a).</em></td>
<td width="253"><em>Place half a spatula end ful in a dry test-tube and heat gently first and then strongly</em></td>
<td width="195"><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="189"><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="43"><em>b).</em></td>
<td width="253"><em>To </em><em>about half a spatula</em> <em>endful in a test tube add </em><em>about 1cm<sup>3</sup> of dilute</em></p>
<p><em>hydrochloric acid</em></td>
<td width="195"><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="189"><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="43"><em>c).</em></td>
<td width="253"><em>Place a half a spatula end- ful in a test tube and </em><em>about </em><em>6cm<sup>3</sup> of distilled water and shake well.</em></p>
<p><em>Divide the solution into</em></p>
<p><em>two portions.</em></td>
<td width="195"> ;</td>
<td width="189"> ;</td>
</tr>
<tr>
<td width="43"><em>i).</em></td>
<td width="253"><em>To the first portion add dilute sodium hydroxide dropwise until in excess. </em><em>Warm the resulting mixture gently then</em></p>
<p><em>strongly.</em></td>
<td width="195"><em> </em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(2 marks)</em></td>
<td width="189"><em> </em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="43"><em>ii).</em></td>
<td width="253"><em>To the second portion add aqueous ammonia</em></p>
<p><em>dropwise until in excess.</em></td>
<td width="195"> ;</td>
<td width="189"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="43"> ;</td>
<td width="253"> ;</td>
<td width="195"><em>(1 mark)</em></td>
<td width="189"><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<h2>OCTOBER /NOVEMBER 1990</h2>
<p><strong> </strong></p>
<ol>
<li><strong><em>(24 marks) </em></strong><em>You are provided with;</em>
<ul>
<li><em>A monobasic acid <strong>solid D</strong></em></li>
</ul>
</li>
</ol>
<ul>
<li><em>Sodium hydroxide, solution <strong>S1</strong></em></li>
<li><em>01 M solution S2 of a dibasic acid H</em><em>2</em><em>A.</em></li>
</ul>
<p> ;</p>
<p>You are required to:</p>
<ul>
<li><em>Prepare a saturated solution of <strong>solid D</strong></em></li>
<li><em>Standardize</em> <em>the</em> <em>sodium</em> <em>hydroxide solution <strong>S1 </strong>using solution <strong>S2</strong>.</em></li>
<li><em>Determine the solubility of <strong>Solid D </strong>in water at room </em></li>
</ul>
<h3>Procedure</h3>
<ul>
<li><em>Place all the <strong>solid D </strong>provided into a dry conical flask. measure out 100cm<sup>3</sup> of distilled water using a measuring cylinder and add it to the <strong>Solid D</strong>. Shake thoroughly and leave it to </em></li>
<li><em>Fill a burette with <strong>solution S1</strong>. Pipette 25cm<sup>3</sup> of <strong>solution S2 </strong>into a conical Titrate with <strong>Solution S1</strong>. Using a phenolphthalein indicator record the readings in the table below. Repeat to obtain three accurate readings.</em></li>
</ul>
<p> ;</p>
<h3>Table A</h3>
<table>
<tbody>
<tr>
<td width="219"> ;</td>
<td width="135"><em>Trial</em></td>
<td width="135"><em>1</em><em>st</em></td>
<td width="135"><em>2</em><em>nd</em></td>
<td width="114"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="219"><em>Final Burette reading</em></td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="114"> ;</td>
</tr>
<tr>
<td width="219"><em>Initial burette reading</em></td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="114"> ;</td>
</tr>
<tr>
<td width="219"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="135"> ;</td>
<td width="114"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>Average titre =&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.. cm<sup>3</sup></p>
<p>(Show the value s being averaged) (1 mark)</p>
<p> ;</p>
<p>Calculations:</p>
<ul>
<li><em>Write the equation for the reaction of the dibasic acid H</em><em>2</em><em>A with sodium </em><em>………………………………… </em><em>(1 mark)</em></li>
<li><em>Calculate the concentration of sodium hydroxide Solution <strong>S1 </strong>in moles per ……………………… ……………… (3 marks)</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Measure the temperature of the solution of <strong>solid D</strong>. Using <strong>a dry filter </strong>paper and <strong>a </strong></em><strong><em>dry filter </em></strong><em> Filter the solution into <strong>a dry conical </strong>flask. Pipette 10cm<sup>3</sup> of the </em><em>f</em><em>i</em><em>l</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e</em><em> into a conical flask, add 25cm<sup>3</sup> of distilled water using a measuring cylinder. Shake well and then titrate with the sodium hydroxide <strong>solution S1</strong>, using phenolphthalein indicator.</em></li>
</ul>
<p> ;</p>
<p>Record the readings in the table below. Repeat to obtain three accurate readings.</p>
<p> ;</p>
<p><em>Temperature of solution of <strong>Solid D </strong>=……………………<sup>o</sup> C </em><em>(1 mark)</em> <strong><em>Table B.</em></strong></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="596">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="234"> ;</td>
<td width="120"><em>Trial</em></td>
<td width="135"><em>1</em><em>st</em></td>
<td width="120"><em>2</em><em>nd</em></td>
<td width="129"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="234"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="135"> ;</td>
<td width="120"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="234"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="135"> ;</td>
<td width="120"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="234"><em>Titre (Cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="135"> ;</td>
<td width="120"> ;</td>
<td width="129"> ;</td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>(6 marks)</p>
<p>Average titre=……………………………………………………………</p>
<p>(Show the values being averaged) (1 mark)</p>
<p> ;</p>
<h3>Calculation;</h3>
<ul>
<li><em>Calculate the number of moles of <strong>acid D </strong>in 10cm<sup>3</sup> of the filtrate,</em></li>
</ul>
<p>(1 mark)</p>
<ul>
<li><em>Calculate the number of moles of <strong>acid D </strong>in 100cm<sup>3</sup> of solution of <strong>acid </strong></em></li>
</ul>
<p>(1 mark) iii). Given that the molecular formula of <strong>acid D </strong>is C7H6O2, calculate the solubility of the acid in grammes per 100cm<sup>3</sup> of water (C=2, H=1, O=16).</p>
<p>(2</p>
<p>marks)</p>
<p> ;</p>
<h3>2. (16marks)</h3>
<p>You are provided with a <strong>solid Q</strong>. Carry out the tests below and record your observations and inferences in the spaces provided on the table below. Test for any gas (es) produced.</p>
<p> ;</p>
<p><strong><em>Table</em></strong></p>
<table>
<tbody>
<tr>
<td width="47"> ;</td>
<td width="322"><em>Test</em></td>
<td width="181"><em>Observations</em></td>
<td width="186"><em>Inferences</em></td>
</tr>
<tr>
<td width="47"><em>a).</em></td>
<td width="322"><em>Place a spatula endful of Solid Q in a boiling tube and add about 20cm<sup>3</sup> of distilled water. Shake well. Use about 2cm<sup>3</sup> portions of</em></p>
<p><em>the solution for the tests below</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>i).</em></td>
<td width="322"><em>Test</em> <em>the</em> <em>pH with a pH paper</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>ii)</em></td>
<td width="322"><em>Add a spatula endful of sodium</em></p>
<p><em>hydrogen</em> <em>carbonate</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>iii).</em></td>
<td width="322"><em>Add two drops of potassium</em></p>
<p><em>manganate (VII)solution</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>iv).</em></td>
<td width="322"><em>Add two drops of bromine water and warm the solution then shake</em></p>
<p><em>it</em> <em>well</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>b).</em></td>
<td width="322"><em>Place a little of solid Q in a</em></p>
<p><em>crucible (a crucible lid or a</em></td>
<td width="181"> ;</td>
<td width="186"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="47"> ;</td>
<td width="322"><em>metallic spatula) and ignite it.</em></td>
<td width="181"><em>(1 mark)</em></td>
<td width="186"><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>c).</em></td>
<td width="322"><em>Place about 4cm<sup>3</sup> of ethanol in a test tube, add two drops of concentrated sulphuric acid then add a spatula endful of Solid Q. Warm the mixture carefully. Shake well and pour the mixture into about 20cm<sup>3</sup> of cold water in a boiling tube. Note any smell</em></td>
<td width="181"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="186"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<h2>OCTOBER / NOVEMBER 1992</h2>
<ol>
<li><em>(15</em> <em>Marks)</em></li>
</ol>
<p>You are provided with:</p>
<ul>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>C</em><em>2</em><em>,</em><em> </em><em>P</em><em>o</em><em>t</em><em>a</em><em>ss</em><em>i</em><em>u</em><em>m</em><em> </em><em>i</em><em>o</em><em>d</em><em>a</em><em>t</em><em>e</em><em> </em><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>C</em><em>3</em><em>,</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>i</em><em>f</em><em>i</em><em>e</em><em>d</em><em> </em><em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em><em> </em><em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>g</em><em>e</em><em>n</em><em> </em><em>s</em><em>u</em><em>l</em><em>phi</em><em>t</em><em>e</em><em> </em><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>C</em><em>4</em><em>,</em><em> </em><em>s</em><em>t</em><em>a</em><em>r</em><em>c</em><em>h</em><em> </em><em>i</em><em>nd</em><em>i</em><em>c</em><em>a</em><em>t</em><em>o</em><em>r</em></li>
<li><em>A stop watch/stop clock</em></li>
</ul>
<p> ;</p>
<p>You are required to find out the effect of the concentration of potassium iodate, <strong>C</strong><strong>2</strong>, on the <strong>rate </strong>of reaction with acidified sodium hydrogen sulphite<strong>, C</strong><strong>3</strong>.</p>
<p> ;</p>
<p><strong>NB: </strong>The end-point for the reaction of potassium iodate with acidified sodium hydrogen sulphite is detected by the formation of a blue- coloured complex using starch indicator.</p>
<p> ;</p>
<h3>Procedure</h3>
<ul>
<li><em>Place solution <strong>C</strong></em><strong><em>2 </em></strong><em>in a burette and measure out the volumes of <strong>C</strong></em><strong><em>2 </em></strong><em>shown in</em></li>
</ul>
<p>table 1 into six dry test-tubes. Using a 10cm<sup>3</sup> measuring cylinder, add distilled water to the test-tubes as shown in table 1.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="255"><em>Test-tube</em></td>
<td width="375"><em>Volume</em><em> </em><em>of <strong>C</strong></em><strong><em>2 </em></strong><em>and water</em></td>
</tr>
<tr>
<td width="255"><em>i).</em></td>
<td width="375"><em>10cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+0 cm<sup>3</sup> distilled water</em></td>
</tr>
<tr>
<td width="255"><em>ii).</em></td>
<td width="375"><em>8cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+ 2 cm<sup>3</sup> distilled water</em></td>
</tr>
<tr>
<td width="255"><em>iii).</em></td>
<td width="375"><em>6cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+ 4cm<sup>3</sup> distilled water</em></td>
</tr>
<tr>
<td width="255"><em>iv).</em></td>
<td width="375"><em>4cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+ 6 cm<sup>3</sup> distilled water</em></td>
</tr>
<tr>
<td width="255"><em>v).</em></td>
<td width="375"><em>3cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+ 7 cm<sup>3</sup> distilled water</em></td>
</tr>
<tr>
<td width="255"><em>vi).</em></td>
<td width="375"><em>2cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>+ 8 cm<sup>3</sup> distilled water</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Using a clean 10cm<sup>3</sup> measuring cylinder, place 10cm<sup>3</sup> of solution <strong>C</strong></em><strong><em>3</em></strong> <em>i</em><em>n</em><em>t</em><em>o</em><em>a </em><em>100cm<sup>3</sup> beaker, add 3 drops of solution <strong>C</strong></em><strong><em>4 </em></strong><em>and shake To this mixture add </em><em>quickly the contents of test-tube (i) and start the stop watch/stop clock immediately. Shake the mixture and note the time taken (in seconds) for the blue colour to appear.</em></li>
</ul>
<p> ;</p>
<p>Record the time in Table II</p>
<p>Repeat this procedure using the other solutions prepared in (a) above and complete Table II</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>TABLE II.</h3>
<table>
<tbody>
<tr>
<td width="165"><em>Volume of <strong>C</strong></em><strong><em>3 </em></strong><em>(cm<sup>3</sup>)</em></td>
<td width="150"><em>Volume of <strong>C</strong></em><strong><em>4 </em></strong><em>(drops)</em></td>
<td width="105"><em>Volume of <strong>C</strong></em></p>
<p><em>(cm<sup>3</sup>)</em></td>
<td width="150"><em>Volume of distilled water</em></p>
<p><em>(cm<sup>3</sup>)</em></td>
<td width="180"><em>Time taken for blue colour to</em></p>
<p><em>appear (seconds)</em></td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>10</em></td>
<td width="150"><em>0</em></td>
<td width="180"> ;</td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>8</em></td>
<td width="150"><em>2</em></td>
<td width="180"> ;</td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>6</em></td>
<td width="150"><em>4</em></td>
<td width="180"> ;</td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>4</em></td>
<td width="150"><em>6</em></td>
<td width="180"> ;</td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>3</em></td>
<td width="150"><em>7</em></td>
<td width="180"> ;</td>
</tr>
<tr>
<td width="165"><em>10</em></td>
<td width="150"><em>3</em></td>
<td width="105"><em>2</em></td>
<td width="150"><em>8</em></td>
<td width="180"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>(6 Marks) c). On the grid below plot a graph of volume (vertical axes) of solution <strong>C</strong><strong>2 </strong>used versus time. (5 Marks)</p>
<p> ;</p>
<ul>
<li><em>From your graph determine the time taken for the blue colour to appear using a mixture of 7cm<sup>3</sup> of <strong>C</strong></em><strong><em>2 </em></strong><em>and 3cm<sup>3</sup> of distilled </em><em>(2 marks)</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>How does the concentration of potassium iodate, <strong>C</strong></em><strong><em>2</em></strong><em>, affect its rate of reaction with acidified sodium hydrogen sulphite, <strong>C</strong></em><strong><em>3</em></strong><em>?</em><em>E</em><em>x</em><em>plai</em><em>n</em><em> </em><em>y</em><em>o</em><em>u</em><em>r</em><em> </em><em>a</em><em>n</em><em>s</em><em>we</em><em>r</em><em>.</em><em> (2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>(15 marks)</em></li>
</ol>
<p> ;</p>
<h3>You are provided with:</h3>
<ul>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em><em>5</em><em>,</em> <em>0</em><em>.</em><em>11</em><em>M</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>C</em><em>6</em><em>,</em><em> </em><em>c</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>i</em><em>n</em><em>g</em><em> </em><em>19</em><em>.</em><em>2</em><em>g</em><em>/</em><em>l</em><em> </em><em>o</em><em>f</em><em> </em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>c</em><em>o</em><em>m</em><em>poun</em><em>d</em><em> </em><em>N</em><em>a</em><em>2</em><em>B</em><em>4</em><em>O</em><em>7</em><strong><em>.</em></strong> <em>n</em><em>H</em><em>2</em><em>O</em></li>
</ul>
<p>You are required to determine the value of n in compound <strong>C</strong><strong>6 </strong>Na2B4O7<strong>. </strong>nH2O.</p>
<p> ;</p>
<h3>Procedure</h3>
<ul>
<li><em>Place</em><em>solution</em><em> </em><strong><em>C</em></strong><strong><em>5</em></strong> <em>in</em><em> </em><em>the</em><em> </em><em> </em><em>Pipette</em><em> </em><em>25.0cm<sup>3</sup> (or 20.0cm<sup>3</sup>) of <strong>C</strong></em><strong><em>6 </em></strong><em>into a 250cm<sup>3</sup> </em><em>conical flask and titrate using methyl orange indicator. Record your results in</em></li>
</ul>
<p>Table III below and repeat the titration carefully to achieve consistent results</p>
<p>Volume of pipette&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.. cm<sup>3</sup></p>
<p>Burette readings</p>
<h3>Table III</h3>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="270"><em>Titration number</em></td>
<td width="120"><em>I</em></td>
<td width="113"><em>II</em></td>
<td width="90"><em>III</em></td>
</tr>
<tr>
<td width="270"><em>Final reading (cm<sup>3</sup>)</em></td>
<td width="120"><em>28.5</em></td>
<td width="113"> ;</td>
<td width="90"> ;</td>
</tr>
<tr>
<td width="270"><em>Initial reading (cm<sup>3</sup>)</em></td>
<td width="120"><em>00.00</em></td>
<td width="113"> ;</td>
<td width="90"> ;</td>
</tr>
<tr>
<td width="270"><em>Volume of <strong>C</strong></em><strong><em>4 </em></strong><em>use (cm<sup>3</sup>)</em></td>
<td width="120"><em>28.5</em></td>
<td width="113"> ;</td>
<td width="90"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks) Average volume of C5 used = ……………………………..cm<sup>3</sup> (1 mark)</p>
<h3>b). Calculations;</h3>
<p>Given that the ionic equation for the reaction is</p>
<p> ;</p>
<p><em>B O </em><em>2-</em></p>
<p><em>+ 2H</em><em>+</em><em>(aq) </em><em>+ 5H</em><em>2</em><em>O</em><em>(l) </em><em>4H</em><em>3</em><em>BO</em><em>3(aq)</em></p>
<p> ;</p>
<p><em>4 7 (aq)</em></p>
<p>(1 mole of the base reacts with two moles of the acid)</p>
<p> ;</p>
<p>i). Calculate the concentration of C6 in moles per litre. (4 marks) ii). Calculate the relative molecular mass of the basic compound <strong>C</strong><strong>6.</strong></p>
<p>(2</p>
<p>marks)</p>
<p>iii). Calculate the value of <strong>n </strong>in the formula Na2B4O7<strong>n</strong>H2O</p>
<p>(B=10.8, H=1.0, Na=23.0, and O = 16.0). (3 marks)</p>
<p> ;</p>
<h3>3. (10 marks).</h3>
<p>You are provided with solid C7. Carry out the following tests and record your Observations and inferences in the spaces provided in table IV.</p>
<p> ;</p>
<p><strong><em>Table IV</em></strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="47"> ;</td>
<td width="322"><em>Test</em></td>
<td width="185"><em>Observations</em></td>
<td width="184"><em>Inferences</em></td>
</tr>
<tr>
<td width="47"><em>a).</em></td>
<td width="322"><em>Place a little of solid <strong>C</strong></em><strong><em>7 </em></strong><em>in a dry </em><em>test-tube and heat gently.</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>b).</em></td>
<td width="322"><em>Place the remainder of the solid <strong>C</strong></em><strong><em>7 </em></strong><em>in a boiling tube. Add about </em><em>10cm<sup>3</sup> of distilled water and shake well to dissolve the solid. Divide the solution into four</em></p>
<p><em>positions for tests (i) to (iv) below</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>( ½ mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>i).</em></td>
<td width="322"><em>To the first portion add a few</em></p>
<p><em>drops of dilute sulphuric acid.</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><em>( ½ mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>ii).</em></td>
<td width="322"><em>To the second portion add dropwise aqueous sodium</em></p>
<p><em>hydroxide until in excess</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><em>( ½ mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>iii).</em></td>
<td width="322"><em>To the third portion add one to</em></p>
<p><em>two drops of aqueous lead nitrate</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><em>( ½ mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="47"><em>iv).</em></td>
<td width="322"><em>To the fourth portion add a few drops of barium chloride solution</em></td>
<td width="185"><strong><em> </em></strong></p>
<p><em>( ½ mark)</em></td>
<td width="184"><strong><em> </em></strong></p>
<p><em>(1 ½</em></p>
<p><em>marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<h2>OCTOBER /NOVEMBER 1993</h2>
<h3>1. (26 MARKS)</h3>
<p><strong> </strong></p>
<p><strong><em>You are provided with:</em></strong></p>
<ul>
<li><em>Sodium hydroxide, solution A</em></li>
<li><em>1</em><em>.</em><em>0</em> <em>g</em> <em>o</em><em>f</em> <em>a</em><em>n</em> <em>a</em><em>mm</em><em>o</em><em>n</em><em>i</em><em>u</em><em>m</em> <em>s</em><em>a</em><em>l</em><em>t</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>B</em></li>
<li><em>0</em><em>.</em><em>01</em><em>M</em><em> monobasic acid, solution C</em></li>
</ul>
<p> ;</p>
<h3>You are required to:</h3>
<ul>
<li><em>Dilute solution <strong>A </strong>with distilled water,</em></li>
<li><em>Standardize the diluted solution <strong>A </strong>with solution C</em></li>
<li><em>Determine the relative formula mass of the ammonium salt <strong>B</strong></em></li>
</ul>
<p><strong> </strong></p>
<h3>Procedure I</h3>
<p>Pipette 25cm<sup>3</sup> <sup>of</sup> solution <strong>A </strong>into a 250cm<sup>3</sup> conical flask, measure 175cm<sup>3</sup> of Distilled water using 100cm<sup>3</sup> measuring cylinder and add it to solution <strong>A </strong>in the beaker. Shake well. Label this as solution D. Pipette 25cm<sup>3</sup> of solution <strong>D </strong>into a 250cm<sup>3</sup> conical flask and then titrate with solution <strong>C </strong>using 1 or 2 drops of Phenolphthalein indicator. Record your results in table I below. Repeat the procedure to obtain accurate values.</p>
<p> ;</p>
<h3>Table I</h3>
<table>
<tbody>
<tr>
<td width="349"><em>Table I</em></td>
<td width="137"><em>1</em><em>st</em></td>
<td width="124"><em>2</em><em>nd</em></td>
<td width="119"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="349"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
<tr>
<td width="349"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
<tr>
<td width="349"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>Calculations:</p>
<p>a). Determine the average volume of solution C used. (1 mark)</p>
<ol>
<li>b) Calculate the concentration in moles per litre, of sodium hydroxide in solution</li>
</ol>
<p>(1 mark)</p>
<p>c). Calculate the concentration, in moles per litre of sodium hydroxide in solution A.</p>
<p>(1 mark)</p>
<p> ;</p>
<p>In the process described below, sodium hydroxide reacts with the ammonium Salt B and on boiling the mixture, ammonia gas is expelled. The excess sodium hydroxide is then determined by titrating the monobasic acid, solution C.</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>Procedure II</h3>
<p>Place all the 1.0g of ammonium salt, solid <strong>B </strong>into 250cm<sup>3</sup> conical flask. Pipette 25cm<sup>3</sup> of the sodium hydroxide solution <strong>A </strong>into the conical flask containing solid <strong>B</strong>. Shake well until all the solid dissolve. Heat the mixture and let it boil for about 10 minutes. Add 50 cm<sup>3</sup> of distilled water to the boiled mixture and shake well. Transfer the solution into a 100cm<sup>3</sup> measuring cylinder then add distilled water up to the 100cm<sup>3</sup> mark. Pour this solution back into the conical flask and label it as solution <strong>E</strong>. Pipette 25cm<sup>3</sup> of solution <strong>E </strong>into a 250 cm<sup>3</sup> conical flask and titrate with solution <strong>C </strong>using 1 or 2 drops phenolphthalein indicator. Record the results in the <strong>table II </strong>below. Repeat the procedure to obtain accurate value and complete <strong>Table II</strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="349"><em>Table I</em></td>
<td width="137"><em>1</em><em>st</em></td>
<td width="124"><em>2</em><em>nd</em></td>
<td width="119"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="349"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
<tr>
<td width="349"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
<tr>
<td width="349"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="137"> ;</td>
<td width="124"> ;</td>
<td width="119"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><u>Calculations:</u></p>
<ul>
<li><em>Determine the average volume of <strong>C </strong> </em><em>(1 mark)</em> <em>b). Calculate:</em>
<ol>
<li><em>T</em><em>h</em><em>e</em> <em>n</em><em>u</em><em>m</em><em>be</em><em>r</em> <em>o</em><em>f</em> <em>m</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>m</em><em>o</em><em>n</em><em>o</em><em>ba</em><em>s</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <strong><em>C</em></strong><em>,</em> <em>u</em><em>s</em><em>e</em><em>d</em></li>
</ol>
</li>
</ul>
<p>(2</p>
<p>marks)</p>
<ul>
<li><em>The</em> <em>number</em> <em>of</em> <em>moles</em> <em>of hydroxide in 25cm<sup>3</sup> of solution <strong>E</strong>. (1 mark)</em></li>
<li><em>The number of moles of sodium hydroxide in 100cm<sup>3</sup> of solution <strong>E</strong>.</em></li>
</ul>
<p>(1</p>
<p>mark)</p>
<ul>
<li><em>Using concentration of sodium hydroxide solution, obtained in (e) above calculate the moles of sodium hydroxide in 25cm<sup>3</sup> of solution <strong>A </strong>(this gives the number of moles of sodium hydroxide added to the ammonium salt <strong>B</strong>)</em></li>
</ul>
<p>(2</p>
<p>marks)</p>
<ul>
<li><em>Using the values obtained in (e) (iii) and (f) above determine the number</em></li>
</ul>
<p>of moles sodium hydroxide that reacted with the ammonium salt.</p>
<p>(2 marks) e). Given that one mole of sodium hydroxide reacts with one mole of the</p>
<p>ammonium Salt <strong>B</strong>, what is the number of moles of salted in 1.0g of Solid <strong>B</strong>.</p>
<p>(2 marks) f). Calculate the relative formula of mass of the ammonium salt. (2 marks)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>2. (14 marks)</h3>
<p>You are provided with solid <strong>F</strong>. You are required to carry out the tests below and write your observation and inferences in the spaces provided. Identify the gas or gases produced.</p>
<p> ;</p>
<p><strong><em>Table</em></strong></p>
<table>
<tbody>
<tr>
<td width="38"> ;</td>
<td width="383"><em>Test</em></td>
<td width="165"><em>Observations</em></td>
<td width="144"><em>Inferences</em></td>
</tr>
<tr>
<td width="38"> ;</td>
<td width="383"><em>Place all the solid <strong>F </strong>provided into a boiling tube and add distilled water with shaking until the boiling tube is half full. Use about 3cm<sup>3</sup> portions of the solution</em></p>
<p><em>for tests (a) to (d) below.</em></td>
<td width="165"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="144"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="38"><strong><em> </em></strong></p>
<p><em>a)</em></td>
<td width="383"><em>To the 1<sup>st</sup> portion add sodium hydroxide</em></p>
<p><em>solution</em> <em>drop wise until in excess</em></td>
<td width="165"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="144"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="38"><em>b)</em></td>
<td width="383"><em>To the 2<sup>nd</sup> portion add about six drops of</em></p>
<p><em>barium chloride solution</em></td>
<td width="165"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="144"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="38"><em>c)</em></td>
<td width="383"><em>To the 3<sup>rd</sup> portion add three drops of</em></p>
<p><em>iodine solution</em></td>
<td width="165"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="144"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="38"><em>d)</em></td>
<td width="383"><em>Dip one end of the filter paper strip provided into potassium dichromate solution and remove it. To the 4<sup>th</sup> portion add about 1cm<sup>3</sup> of dilute hydrochloric acid, shake well, and observe for about 2 minutes. Place the dipped end of the filter paper at the mouth of the test tube and warm the contents of the test tube</em></p>
<p><em>gently.</em></td>
<td width="165"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(3 marks)</em></td>
<td width="144"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(3 marks)</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<h2>OCTOBER / NOVEMBER 1994</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>2M sodium hydroxide, solution <strong>D</strong></em></li>
<li><em>1M solution of a carboxylic acid C</em><em>3</em><em>H</em><em>5</em><em>O (COOH) n solution <strong>E</strong></em></li>
</ul>
<p>You are required to determine the value of n in the formula C3H5O (COOH)n of the carboxylic acid E</p>
<p> ;</p>
<h3>Procedure</h3>
<ul>
<li><em>Place solution <strong>D </strong>in the Pipette 25.0cm<sup>3</sup> (or 20.0cm<sup>3</sup>) of solution E into a conical flask and titrate with solution <strong>D </strong>using phenolphthalein indicator. Record </em><em>your</em></li>
</ul>
<p> ;</p>
<p>results in <strong>table l </strong>below and repeat the titration to achieve consistent results.</p>
<p> ;</p>
<h3>Results</h3>
<p>Volume of pipette&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230; cm<sup>3</sup></p>
<h3>Table I</h3>
<p>Burette readings</p>
<table>
<tbody>
<tr>
<td width="240"><em>Titration number</em></td>
<td width="165"><em>I</em></td>
<td width="135"><em>II</em></td>
<td width="129"><em>III</em></td>
</tr>
<tr>
<td width="240"><em>Final reading (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="240"><em>Initial reading (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="240"><em>Volume of D used (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
</tbody>
</table>
<p>4 marks</p>
<ul>
<li><em>Average volume of D…………………</em></li>
</ul>
<p>(Show how you arrive at your answer)</p>
<ul>
<li><em>Calculate</em> <em>the</em> <em>number</em> <em>of</em> <em>moles</em> <em>of</em> <em>sodium</em> <em>hydroxide 2 marks</em></li>
<li><em>Calculate the number of moles of E in the 0cm<sup>3</sup> (or 20.0cm<sup>3</sup>) used</em></li>
</ul>
<p> ;</p>
<p>2 marks</p>
<ul>
<li><em>i). Calculate the number of moles of sodium hydroxide required to react with one mole of C</em><em>3</em><em>H</em><em>5</em><em>O(COOH)</em><em>n </em><em>3 marks</em></li>
</ul>
<p>ii). What is the value of n 1 mark</p>
<p> ;</p>
<h3>2. You are provided with;</h3>
<p>1.0M Sodium hydroxide solution F 0.63M solution of an acid solution G</p>
<p> ;</p>
<p>You are required to determine the molar heat of neutralization of sodium hydroxide with acid <strong>G.</strong></p>
<p><strong> </strong></p>
<h3>Procedure</h3>
<p>a). Place six test-tubes on a test-tube rack. Using a 10cm<sup>3</sup> measuring cylinder, measure 5cm<sup>3</sup> portions of solution <strong>G </strong>and place them into each of the six test- tubes.</p>
<p> ;</p>
<p>Measure 25.0cm<sup>3</sup> of solution <strong>F </strong>using a measuring cylinder and place it into a 100cm<sup>3</sup> beaker. Measure the temperature of this solution F to the nearest 0.5<sup>0</sup>C and record it in <strong>table II.</strong></p>
<p><strong> </strong></p>
<p>Pour the first portion of the 5cm<sup>3</sup> of solution <strong>G </strong>from the test-tube into the beaker containing 25cm<sup>3</sup> of solution <strong>F</strong>, stir the mixture carefully and record the highest temperature of the mixture in <strong>table II.</strong></p>
<p><strong> </strong></p>
<p>Pour the second portion of solution <strong>G immediately </strong>into the mixture in the beaker, stir carefully and record the highest temperature of this mixture in <strong>Table II</strong>. Continue this procedure using the remaining portions of solution G to Complete <strong>table II.</strong></p>
<h3>Table II</h3>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="83"><em>24</em></td>
<td width="29"><em>Ch</em></td>
<td width="300"><em>e</em><em>m</em><em>T</em><em>o</em><em>i</em><em>s</em><em>t</em><em>t</em><em>a</em><em>r</em><em>y</em><em>l</em><em> </em><em>P</em><em>v</em><em>o</em><em>r</em><em>a</em><em>l</em><em>c</em><em>u</em><em>t</em><em>m</em><em>i</em><em>c</em><em>a</em><em>e</em><em>l</em> <em>S</em><em>o</em><em>t</em><em>f</em><em>u</em><em>G</em><em>d</em><em>y</em><em>a</em><em>P</em><em>d</em><em>a</em><em>d</em><em>c</em><em>k</em><em>e</em><em>d</em><em> </em><em>(</em><em>c</em><em>m</em><em>3</em><em>)</em></td>
<td width="47"><em>1</em><em>9</em><em>0</em><em>8</em><em>9</em></td>
<td width="53"><em>&#8211;</em> <em>5</em><em>2016</em></td>
<td width="53"><em>10</em></td>
<td width="53"><em>15</em></td>
<td width="45"><em>20</em></td>
<td width="53"><em>25</em></td>
<td width="53"><em>30</em></td>
<td width="32"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="300"><em>Volume of F (cm<sup>3</sup>)</em></td>
<td width="47"><em>25</em></td>
<td width="53"><em>25</em></td>
<td width="53"><em>25</em></td>
<td width="53"><em>25</em></td>
<td width="45"><em>25</em></td>
<td width="53"><em>25</em></td>
<td width="53"><em>25</em></td>
</tr>
<tr>
<td width="300"><em>Temperature (<sup>0</sup>C)</em></td>
<td width="47"> ;</td>
<td width="53"> ;</td>
<td width="53"> ;</td>
<td width="53"> ;</td>
<td width="45"> ;</td>
<td width="53"> ;</td>
<td width="53"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p>mark</p>
<p>4 marks</p>
<ul>
<li><em>On the grid provided below, plot a graph of temperature (vertical axes) versus volume of solution G added 4 marks</em></li>
<li><em>From the graph determine:</em></li>
<li><em>The volume of the solution G required to neutralize 25cm<sup>3</sup> sodium hydroxide solution F </em><em>1 mark</em></li>
<li><em>T</em><em>h</em><em>e</em> <em>h</em><em>i</em><em>g</em><em>he</em><em>s</em><em>t</em> <em>t</em><em>e</em><em>m</em><em>pe</em><em>r</em><em>a</em><em>t</em><em>u</em><em>r</em><em>e</em> <em>c</em><em>h</em><em>a</em><em>n</em><em>g</em><em>e</em><em>,</em> <em>â</em><em>T</em><em>,</em><em> 1 mark</em></li>
<li><em>Calculate the heat change for the reaction. (Heat change = mass x temperature change x 4.2Jg<sup>-1</sup> <sup>0</sup>C<sup>-1</sup>. Assume density of each solution to be 1gm cm<sup>-3</sup>) 2 marks</em></li>
<li><em>Calculate the number of moles of sodium hydroxide, solution F, </em></li>
</ul>
<p>1</p>
<p> ;</p>
<ul>
<li><em>Calculate the molar heat of neutralization of the sodium hydroxide solution 1 mark</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><em>a). You are provided with the following solids:</em></li>
</ol>
<p>Sodium chloride, potassium chloride, calcium chloride and solid H Note: Solid H will also be required for Question 3 (b)</p>
<p> ;</p>
<p>You are required to carry out flame tests on the above solids to identify the flame colour of the <strong>cations </strong>present in each of them.</p>
<p> ;</p>
<h3>Procedure:</h3>
<p>Clean a metallic spatula and rinse it with distilled water. Dry the spatula on a Bunsen flame for about 1 minute. Allow it to cool. Place a little of sodium chloride solid of the flame as the solid burns and record it in <strong>Table III </strong>below. Clean the spatula thoroughly using steel wool, and repeat the procedure using each of the other solids and complete the <strong>Table III.</strong></p>
<p><strong> </strong></p>
<h3>i). Table III</h3>
<table>
<tbody>
<tr>
<td width="233"><em>Solid</em></td>
<td width="450"><em>Colour of flame</em></td>
</tr>
<tr>
<td width="233"><em>Sodium chloride</em></td>
<td width="450"> ;</td>
</tr>
<tr>
<td width="233"><em>Potassium chloride</em></td>
<td width="450"> ;</td>
</tr>
<tr>
<td width="233"><em>Calcium chloride</em></td>
<td width="450"> ;</td>
</tr>
<tr>
<td width="233"><em>Solid H</em></td>
<td width="450"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>4 marks</p>
<p> ;</p>
<ul>
<li><em>What cation is present in solid H? 1 mark</em></li>
</ul>
<p>b). You are provided with solid H. Carry out the tests in table IV below and record your observations and inferences in the spaces provided. Identify</p>
<p> ;</p>
<p>any gas (es) produced.</p>
<p> ;</p>
<p><strong><em>Table IV</em></strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="45"> ;</td>
<td width="360"><em>Test</em></td>
<td width="183"><em>Observation</em></td>
<td width="141"><em>Inferences</em></td>
</tr>
<tr>
<td width="45"><em>i).</em></td>
<td width="360"><em>Place a little of solid H in a dry test-</em></p>
<p><em>tube and heat strongly</em></td>
<td width="183"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="141"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>ii).</em></td>
<td width="360"><em>Place the remainder of the solid H in a boiling tube. Add about 10cm<sup>3</sup> of distilled water and shake well. Divide the mixture into three portions for</em></p>
<p><em>tests (I to III) below</em></td>
<td width="183"> ;</td>
<td width="141"> ;</td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="360"><em>I. To the first portion add aqueous</em></p>
<p><em>sodium</em> <em>hydroxide until in excess</em></td>
<td width="183"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="141"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="360"><em>II. To the second portion add</em></p>
<p><em>aqueous ammonia until in excess</em></td>
<td width="183"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="141"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="360"><em>III. To the third portion add about</em></p>
<p><em>1cm<sup>3</sup> aqueous sodium chloride</em></td>
<td width="183"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
<td width="141"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong> </strong></p>
<h1>October /November 1995</h1>
<ol>
<li><em>(22 Marks).</em></li>
</ol>
<p> ;</p>
<h3>You are provided with</h3>
<ul>
<li><em>0g of potassium hydrogen carbonate solid J</em></li>
<li><em>1</em><em>.</em><em>0</em><em>g</em> <em>o</em><em>f</em> <em>m</em><em>a</em><em>g</em><em>n</em><em>e</em><em>s</em><em>i</em><em>u</em><em>m</em> <em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>K</em></li>
<li><em>0M Hydrochloric acid</em></li>
</ul>
<p> ;</p>
<p>You are required to determine the enthalpy change for the reaction between a). Potassium hydrogen carbonate and hydrochloric acid</p>
<ul>
<li><em>Magnesium carbonate and hydrochloric acid</em></li>
<li><em>Aqueous magnesium chloride and aqueous potassium hydrogen </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>Procedure</h3>
<ol>
<li><em>By means of a burette place 15.0cm<sup>3</sup> of the 2.0M hydrochloric acid in a 100cm<sup>3</sup> Stir gently and take the temperature of the acid at every half-minute. Record your readings in table 1. at exactly 2½ minutes add all solid J to the acid, stir gently and continue taking the temperature every half-minute 5 record your</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="582">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="133"><em>Time (min)</em></td>
<td width="37"><em>0</em></td>
<td width="56"><em>½</em></td>
<td width="54"><em>1</em></td>
<td width="56"><em>1 ½</em></td>
<td width="54"><em>2</em></td>
<td width="56"><em>2 ½</em></td>
<td width="54"><em>3</em></td>
<td width="56"><em>3 ½</em></td>
<td width="54"><em>4</em></td>
<td width="56"><em>4 ½</em></td>
<td width="54"><em>5</em></td>
</tr>
<tr>
<td width="133"><em>Temperature</em></p>
<p><em>(0<sup>C</sup>)</em></td>
<td width="37"> ;</td>
<td width="56"> ;</td>
<td width="54"> ;</td>
<td width="56"> ;</td>
<td width="54"> ;</td>
<td width="56"> ;</td>
<td width="54"> ;</td>
<td width="56"> ;</td>
<td width="54"> ;</td>
<td width="56"> ;</td>
<td width="54"> ;</td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>readings in table I. <strong>Table</strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p>On the grid provided plot a graph of temperature against time and determine from it the fall in temperature âT1. Show the change âT1 on the graph</p>
<p>(3</p>
<p>marks)</p>
<p>Fall in temperature âT1 (1 mark)</p>
<p>Calculations; use the following information where necessary</p>
<p>(H=1, C=12, O=16, Mg=24, k=39) Assume density of the solutions to be 1.0gcm<sup>3</sup></p>
<p> ;</p>
<h3>a). Calculate;</h3>
<ul>
<li><em>T</em><em>h</em><em>e</em><em>n</em><em>u</em><em>m</em><em>be</em><em>r</em><em> </em><em>o</em><em>f</em><em> </em><em>m</em><em>o</em><em>l</em><em>e</em><em>s</em><em>,</em><em> </em><em>n</em><em>1</em><em>,</em><em> </em><em>o</em><em>f</em><em> </em><em>po</em><em>t</em><em>a</em><em>ss</em><em>i</em><em>u</em><em>m</em><em> </em><em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>g</em><em>e</em><em>n</em><em> </em><em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e</em><em> </em><em>(</em><em>K</em><em>H</em><em>C</em><em>O</em><em>3</em><em>) </em><em>used during procedure I (1 mark)</em></li>
<li><em>The enthalpy, change âH</em><em>2 </em><em>for the reaction between potassium </em><em>hydrogen carbonate and hydrochloric acid. Show the sign. Use the following expression (2 marks)</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>Calculate;</em></li>
</ul>
<p><em>âH</em><em>1 = </em><em><u>Mass of solution x 4.2 x âT</u></em><em><u>1</u></em></p>
<p><em>n</em><em>1 </em><em>x 1000</em></p>
<p><em>-1</em></p>
<p><em>Kjmol</em></p>
<p> ;</p>
<ul>
<li><em>T</em><em>h</em><em>e</em><em>n</em><em>u</em><em>m</em><em>be</em><em>r</em><em> </em><em>o</em><em>f</em><em> </em><em>m</em><em>o</em><em>l</em><em>e</em><em>s</em><em> </em><em>N</em><em>2</em><em>,</em><em> </em><em>o</em><em>f</em><em> </em><em>m</em><em>a</em><em>g</em><em>n</em><em>e</em><em>s</em><em>i</em><em>u</em><em>m</em><em> </em><em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e</em><em> </em><em>(</em><em>M</em><em>g</em><em>C</em><em>O</em><em>3</em><em>)</em><em> </em><em>u</em><em>s</em><em>e</em><em>d</em><em> </em><em>i</em><em>n </em><em>procedure II </em><em>(1 mark)</em></li>
<li><em>T</em><em>h</em><em>e</em><em> enthalpy change âH</em><em>2</em><em>,</em><em> </em><em>f</em><em>o</em><em>r</em><em> the reaction between magnesium </em><em>carbonate and hydrochloric acid. Show the sign. Use the following </em></li>
</ul>
<p> ;</p>
<p>Mass of solution x 4.2 x âT2</p>
<p>âH2 =<u> </u>Kjmol<sup>-1</sup></p>
<p>n2 x 1000 (2 marks)</p>
<p> ;</p>
<ul>
<li><em>The equations for the reactions taking place in procedures I and II are; </em><em>KHCO</em><em>3(s) </em><em>+ HCl</em><em>(aq) </em><em>KCI</em><em>(aq) </em><em>+ CO</em><em>2(q) </em><em>+ H</em><em>2</em><em>O</em><em>(l)</em></li>
</ul>
<p><em>and MgCO</em><em>4(s) </em><em>+ 2HCl</em><em>(aq) </em><em>MgCl</em><em>2 (aq) </em><em>+ CO</em><em>2(q) </em><em>+ H</em><em>2</em><em>O</em><em>(l) </em><em>Gi</em><em>v</em><em>e</em><em>n</em><em> </em><em>t</em><em>h</em><em>a</em><em>t</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>e</em><em>n</em><em>t</em><em>h</em><em>a</em><em>l</em><em>p</em><em>y</em><em> </em><em>c</em><em>h</em><em>a</em><em>n</em><em>g</em><em>e</em><em>,</em><em> </em><em>â</em><em>H</em><em>3</em> <em>f</em><em>o</em><em>r</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>p</em><em>r</em><em>o</em><em>c</em><em>e</em><em>ss</em><em>.</em></p>
<p><em>KHCO</em><em>3 (s) </em><em>KHCO</em><em>3(aq) </em><em>= 121 kjmol<sup>-1</sup> determine the Enthalpy</em></p>
<p>change âH4 for the reaction represented by the equation</p>
<p> ;</p>
<p><em>MgCl</em><em>2(aq) </em><em>+ 2KHCO</em><em>3(aq) </em><em>MgCO</em><em>3(s) </em><em>+ 2KCl</em><em>(aq) </em><em>+ H</em><em>2</em><em>O</em><em>(l) </em><em>+ CO</em><em>2(g)</em></p>
<p>Use the following expression</p>
<p>âH4=2âH1 &#8211; âH2- 2âH3 (2 marks)</p>
<p> ;</p>
<h3>2. (9 Marks)</h3>
<p>You are provided with solid L. You are required to carry out the tests below and write your observations and inferences in the spaces provided.</p>
<p> ;</p>
<h3>Identify any gases evolved</h3>
<p>a). Describe the appearance of solid L (1 mark) b). Place a little of solid L, in a dry clean test tube and heat strongly</p>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark)</p>
<ul>
<li><em>Place a little L in a dry clean test tube then add about 2cm<sup>3</sup> of distilled Shake well then warm the mixture</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark)</p>
<ul>
<li><em>Place a little solid L in a dry clean test tube then add about 2cm<sup>3</sup> of dilute hydrochloric acid</em></li>
</ul>
<p>Observations inferences</p>
<p> ;</p>
<p>(1</p>
<p>mark)</p>
<ul>
<li><em>place about 2cm<sup>3</sup> of lead nitrate solution in a clean test tube, add a little of </em><em>solid L Shake well and allow to settle for about 5 minutes</em></li>
</ul>
<table>
<tbody>
<tr>
<td width="178"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><em>(9 marks)</em></li>
</ol>
<p>You are provided with solid N. You are required to carry out the tests below and record your observations and inferences in the spaces provided. Identify any gases evolved using a glowing splint and litmus paper</p>
<p>a). Describe the appearance of Solid N. (1 mark) b). Place a little of Solid N on a clean metallic spatula and burn it in a</p>
<p>Bunsen flame (1 mark)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p>mark)</p>
<ul>
<li><em>Place a little of Solid N in a dry clean test tube and heat strongly </em><em>Observations inferences</em></li>
</ul>
<p>(1</p>
<p> ;</p>
<p> ;</p>
<p>d). Place the remaining solid N in a boiling tube and add about 20cm<sup>3</sup> of distilled water. Shake well until all the solid dissolves. Use about 2cm<sup>3</sup> portions of this solution for the tests below.</p>
<p>i). Test the 1<sup>st</sup> portion with red and blue litmus papers Observations Inferences</p>
<p> ;</p>
<p> ;</p>
<p>ii).</p>
<p>To the 2<sup>nd</sup> portion add a shake well after every drop Observations</p>
<p>(1 mark)</p>
<p> ;</p>
<p>few drops of dilute sodium hydroxide</p>
<p> ;</p>
<p>Inferences</p>
<p> ;</p>
<p>(1 mark)</p>
<p> ;</p>
<ul>
<li><em>To</em> <em>the</em> <em>3<sup>rd</sup></em> <em>portion</em> <em>add</em> <em>a</em> <em>few</em> <em>drops</em> <em>of</em> <em>dilute</em> <em>lead</em> <em>Shake well after every drop</em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark)</p>
<p> ;</p>
<ul>
<li><em>To the 4<sup>th</sup> portion add about 1cm<sup>3</sup> of dilute sodium hydroxide </em><em>followed by a small piece of aluminium Warm the mixture gently and carefully</em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER /NOVEMBER 1996</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>A</em><em>c</em><em>i</em><em>d</em><em>i</em><em>f</em><em>i</em><em>e</em><em>d</em><em>a</em><em>q</em><em>u</em><em>e</em><em>o</em><em>u</em><em>s</em><em> </em><em>po</em><em>t</em><em>a</em><em>ss</em><em>i</em><em>u</em><em>m</em><em> </em><em>m</em><em>a</em><em>n</em><em>g</em><em>a</em><em>n</em><em>a</em><em>t</em><em>e</em><em> </em><em>(</em><em>V</em><em>II</em><em>)</em><em> </em><em>K</em><em>M</em><em>n</em><em>O</em><em>4</em><strong><em>,</em></strong><strong><em> </em></strong><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><em>A</em><em>.</em></li>
<li><em>Solution <strong>B</strong>, containing 5g of ammonium Iron (II) Sulphate (NH</em><em>4</em><em>)</em><em>2</em><em>Fe (SO</em><em>4</em><em>)</em><em>2 </em><em>6</em><em>H</em><em>2</em><em>O</em><em>,</em><em>pe</em><em>r</em><em> </em><em>l</em><em>i</em><em>t</em><em>r</em><em>e</em><em>.</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><strong><em>C</em></strong><em>,</em><em> </em><em>C</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>i</em><em>n</em><em>g</em><em> </em><em>5</em><em>.</em><em>0</em><em>g</em><em> </em><em>o</em><em>f</em><em> </em><em>a</em><em> </em><em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>,</em><em> </em><em>H</em><em>2</em><em>X</em><em> </em><em>2</em><em>H</em><em>2</em><em>O</em><em>,</em><em> </em><em>pe</em><em>r</em><em> </em><em>l</em><em>i</em><em>t</em><em>r</em><em>e</em></li>
</ul>
<p> ;</p>
<h3>You are required to:</h3>
<p> ;</p>
<ul>
<li><em>S</em><em>t</em><em>a</em><em>nd</em><em>a</em><em>r</em><em>d</em><em>i</em><em>z</em><em>e</em><em> the potassium manganate (VII), solution A, using the ammonium iron (II) sulphate, solution <strong>B.</strong></em></li>
<li><em>Use the standardized potassium manganate (VII), solution A, to determine theconcentration of the dibasic acid, H</em><em>2</em><em>X</em><em> </em><em>2</em><em>H</em><em>2</em><em>O</em><em>,</em><em> </em><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><strong><em>C</em></strong><strong><em> </em></strong><em>a</em><em>n</em><em>d</em><em> </em><em>t</em><em>he</em><em>n</em><em> </em><em>t</em><em>h</em><em>e </em><em>formula mass of </em></li>
</ul>
<p><strong> </strong></p>
<h3>Procedure I:</h3>
<p><strong> </strong></p>
<p><strong><em>Fill the burette with solution A.</em></strong></p>
<p>Pipette 25.0cm<sup>3</sup> of solution B into a conical flask. Titrate solution <strong>B </strong>with solution A until a permanent pink colour just appears. Record your results in table I below. Repeat this procedure to complete table I.</p>
<p> ;</p>
<p><em>a). <strong>Table I</strong></em></p>
<table>
<tbody>
<tr>
<td width="281"> ;</td>
<td width="135"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="144"><em>III</em></td>
</tr>
<tr>
<td width="281"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="135"> ;</td>
<td width="105"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="281"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="135"> ;</td>
<td width="105"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="281"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="135"> ;</td>
<td width="105"> ;</td>
<td width="144"> ;</td>
</tr>
</tbody>
</table>
<p>4 marks b). Record average volume of solution A used, V1 cm<sup>3</sup></p>
<p>(Show how you arrive at your answer) 1 mark</p>
<p> ;</p>
<ul>
<li><em>C</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>c</em><em>o</em><em>n</em><em>c</em><em>e</em><em>n</em><em>t</em><em>r</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>a</em><em>mm</em><em>o</em><em>n</em><em>i</em><em>u</em><em>m</em> <em>i</em><em>r</em><em>o</em><em>n</em> <em>(</em><em>II</em><em>)</em> <em>s</em><em>u</em><em>l</em><em>pha</em><em>t</em><em>e</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>B</em><em>, </em><em>in moles per (RFM of (NH</em><em>4</em><em>)2 Fe (SO</em><em>4</em><em>)</em><em>2 </em><strong><em>.</em></strong><em>6H</em><em>2</em><em>O = 392 1 mark</em></li>
<li><em>Calculate</em> <em>the</em> <em>number</em> <em>of</em> <em>moles</em> <em>of</em> <em>iron</em> <em>(II)</em> <em>ions</em> <em>in</em> <em>the</em> <em>0cm<sup>3</sup></em> <em>of solution B</em></li>
</ul>
<p>1 mark</p>
<ul>
<li><em>Using the ionic equation for the reaction between manganate (VII) and iron</em></li>
</ul>
<p>(II) ions, given below, calculate the concentration of manganate (VII) ions in solution A in moles per litre.</p>
<p> ;</p>
<p><em>MnO</em><em>4(aq) </em><em>+ 5Fe</em><em>2+</em><em>(aq) </em><em>+ 8H</em><em>+</em><em>(aq) </em><em>Mn</em><em>2+</em><em>(aq)</em> <em>+ 5Fe</em><em>3+</em><em>(aq) </em><em>+ 4H</em><em>2</em><em>O</em><em>(l)</em></p>
<p> ;</p>
<p> ;</p>
<h3>Procedure II</h3>
<p>Pipette 25.0cm<sup>3</sup> of solution <strong>C </strong>into a conical flask. Heat this solution to about 70<sup>0</sup>C and titrate the hot solution <strong>C </strong>with solution <strong>A </strong>until a permanent pink colour just appears. Shake the thoroughly during the titration. Record your results in <strong>table II. </strong>Repeat this procedure to complete <strong>Table II.</strong></p>
<p><strong> </strong></p>
<h3>f). Table II.</h3>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="270"> ;</td>
<td width="83"><em>I</em></td>
<td width="125"><em>II</em></td>
<td width="185"><em>III</em></td>
</tr>
<tr>
<td width="270"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="83"> ;</td>
<td width="125"> ;</td>
<td width="185"> ;</td>
</tr>
<tr>
<td width="270"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="83"> ;</td>
<td width="125"> ;</td>
<td width="185"> ;</td>
</tr>
<tr>
<td width="270"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="83"> ;</td>
<td width="125"> ;</td>
<td width="185"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p>marks</p>
<p>4 marks g). Record average volume of solution A used V2=&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230; cm<sup>3</sup></p>
<p>Show how you arrive at your answer.</p>
<ul>
<li><em>Calculate the number of moles of the manganate (VII) ions in volume V</em><em>2</em></li>
</ul>
<p>1 mark</p>
<ul>
<li><em>Given that 2 moles of the manganate (VII) ions react with 5 moles of the dibasicacid, H</em><em>2</em><em>X</em><em>.</em><em> </em><em>2</em><em>H</em><em>2</em><em>O</em><em>,</em><em> </em><em>c</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>n</em><em>u</em><em>m</em><em>be</em><em>r</em><em> </em><em>o</em><em>f</em><em> </em><em>m</em><em>o</em><em>l</em><em>e</em><em>s</em><em> </em><em>o</em><em>f</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>,</em></li>
</ul>
<p>H2X 2H2O, in the 25cm<sup>3</sup> of solution C. 2 marks</p>
<ul>
<li><em>C</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em><em>t</em><em>h</em><em>e</em><em> </em><em>c</em><em>o</em><em>n</em><em>c</em><em>e</em><em>n</em><em>t</em><em>r</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><em>o</em><em>f</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>,</em><em> </em><em>H</em><em>2</em><em>X</em><em>.</em><em> </em><em>2</em><em>H</em><em>2</em><em>O</em><em> </em><em>i</em><em>n</em><em> </em><em>m</em><em>o</em><em>l</em><em>e</em><em>s</em><em> </em><em>pe</em><em>r </em><em>litre 1 mark</em></li>
<li><em>Calculate the formula mass of x in the dibasic acid H</em><em>2</em><em> 2H</em><em>2</em><em>O</em></li>
</ul>
<p>(H = 1.0 O=16.0) 3</p>
<p> ;</p>
<p> ;</p>
<ol start="2">
<li><strong><em>(8 marks) </em></strong><em>You are provided with solid Carry out the tests below.</em></li>
</ol>
<p>Record observations and inferences in the table. Identify any gas (es) evolved.</p>
<p> ;</p>
<p>Divide solid D into portions</p>
<p> ;</p>
<ul>
<li><em>i). To one portion of D in a dry test-tube add about 1cm<sup>3</sup> of 6M hydrochloric acid and warm gently for about one minute</em></li>
</ul>
<p>Observation s Inferences</p>
<p> ;</p>
<p>2 marks 1 mark</p>
<p> ;</p>
<p>ii). Add distilled water to the mixture in (a) (i) above until the test-tube is about half-full. Shake well and filter into a boiling tube. To about 1cm<sup>3</sup> of the filtrate in a test-tube add about 1cm<sup>3</sup>of 2M sodium hydroxide drop wise</p>
<p>Observations 2 marks</p>
<table>
<tbody>
<tr>
<td width="224"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<ul>
<li><em>Place the remaining portion of D in a dry test-tube and about 1cm<sup>3</sup> of 20 </em><em>volume hydrogen peroxide</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><strong><em>(11marks) </em></strong><em>You are provided with solid Carry out the tests below and record </em><em>the observations and inferences in the spaces provided. Identify any gas (es) produced.</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Place a little of E on a clean metallic spatula and ignite with a bunsen </em></li>
</ul>
<p>Observations inferences</p>
<p><em>31 Chemistry Practical Study Pack 1989 &#8211; 2016</em></p>
<p> ;</p>
<ul>
<li><em>mark 1 mark</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Add a little of solid E to about 2cm<sup>3</sup> of distilled water in a test-tube and </em><em>shake Test the mixture with litmus paper.</em></li>
</ul>
<p>Observations inferences</p>
<p> ;</p>
<ul>
<li><em>marks </em><em>1 mark</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Add</em> <em>a</em> <em>little</em> <em>of</em> <em>solid</em> <em>E</em> <em>to</em> <em>about</em> <em>2cm<sup>3</sup></em> <em>of</em> <em>2M</em> <em>aqueous</em> <em>sodium hydroxide in a test-tube and shake well</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Place the remaining portion of E in a boiling tube, add about 10cm<sup>3</sup> of </em><em>distilled water and heat the Divide the mixture, while still hot, </em><em>into</em> <em>two portions:</em>
<ul>
<li><em>Add a little of solid sodium hydrogen carbonate to the first portion </em><em>Observations inferences</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p>1 mark 1 mark</p>
<ul>
<li><em>Add about 2-3 drops of concentrated sulphuric acid to the second Shake well, and then add about 1cm<sup>3</sup> of ethanol. Warm the mixture.</em></li>
</ul>
<h2>OCTOBER /NOVEMBER 1997</h2>
<ol>
<li><em>You are provided with;</em>
<ul>
<li><em>S</em><em>u</em><em>l</em><em>phu</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>F</em></li>
<li><em>5M sodium hydroxide, solution G</em></li>
<li><em>M</em><em>a</em><em>g</em><em>n</em><em>e</em><em>s</em><em>i</em><em>u</em><em>m</em> <em>t</em><em>u</em><em>r</em><em>n</em><em>i</em><em>n</em><em>g</em><em>s</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>H</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<p>You are required to determine the concentration of sulphuric acid in moles per litre</p>
<p> ;</p>
<h3>Procedure I</h3>
<p>Measure 50cm<sup>3</sup> of solution <strong>F </strong>using a measuring cylinder and place it in a 100 cm<sup>3</sup> beaker. Stir the solution gently with a thermometer and take its temperature after every half-minute. Record your results in <strong>Table I.</strong></p>
<p><strong> </strong></p>
<p>After one and half minutes, add all of solid <strong>H </strong>at once. Stir the mixture gently with the thermometer and record the temperature of the mixture after every half-minute in table <strong>I</strong></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="635">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="133"><em>Time (min)</em></td>
<td width="45"><em>0</em></td>
<td width="45"><em>½</em></td>
<td width="45"><em>1</em></td>
<td width="60"><em>1 ½</em></td>
<td width="45"><em>2</em></td>
<td width="60"><em>2 ½</em></td>
<td width="45"><em>3</em></td>
<td width="60"><em>3 ½</em></td>
<td width="45"><em>4</em></td>
<td width="60"><em>4 ½</em></td>
<td width="34"><em>5</em></td>
<td width="55"><em>5 ½</em></td>
<td width="55"><em>6</em></td>
</tr>
<tr>
<td width="133"><em>Temperature</em></p>
<p><em>(<sup>0</sup>C)</em></td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="60"> ;</td>
<td width="45"> ;</td>
<td width="60"> ;</td>
<td width="45"> ;</td>
<td width="60"> ;</td>
<td width="45"> ;</td>
<td width="60"> ;</td>
<td width="34"> ;</td>
<td width="55"> ;</td>
<td width="55"> ;</td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p>up to the sixth minute. Keep the solution for use in procedure <strong>II </strong>a). Table I</p>
<p> ;</p>
<p> ;</p>
<p>(5 marks) b). Using the results in table I, determine the highest change in temperature,</p>
<p>âT for the reaction</p>
<p>âT………………. (1 mark)</p>
<p>c). Calculate the heat change for the reaction using the expression Heat change = Mass of solution x 4.2 x âT Joules</p>
<p>(Assume density of solution = 1.0g/cm<sup>3</sup>) (3 marks) d). Given that the molar heat of reaction of sulphuric acid with solid H is</p>
<p>323KJ mol<sup>-1</sup>, calculate the number of moles of sulphuric acid that were used during the reaction (2 marks)</p>
<p> ;</p>
<h3>Procedure II</h3>
<p>Place <strong>all </strong>the solution obtained in procedure <strong>I </strong>in a clean <strong>100m<sup>3</sup> measuring cylinder. </strong>Add distilled water to make 100cm<sup>3</sup> of solution. Transfer all the solution. Transfer all the solution into a beaker and shake well. The resulting solution is ‘solution <strong>K’</strong>.</p>
<p> ;</p>
<p>Fill a burette with solution <strong>G</strong>. Pipette 25.0cm<sup>3</sup> of solution <strong>K </strong>into a conical flask. Add 2- 3 drops of phenolphthalein indicator and titrate with solution <strong>G</strong>. Record your results in table II. Repeat the titration two more times.</p>
<h3>Table II.</h3>
<table>
<tbody>
<tr>
<td width="330"> ;</td>
<td width="120"><strong><em>I</em></strong></td>
<td width="113"><strong><em>II</em></strong></td>
<td width="150"><strong><em>III</em></strong></td>
</tr>
<tr>
<td width="330"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="113"> ;</td>
<td width="150"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="113"> ;</td>
<td width="150"> ;</td>
</tr>
<tr>
<td width="330"><em>Volume of solution G used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="113"> ;</td>
<td width="150"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p>mark)</p>
<p> ;</p>
<p>mark)</p>
<p>(6 marks) e). Determine the average volume of solution <strong>G </strong>used (1 mark)</p>
<ul>
<li><em>Calculate the number of moles of sodium hydroxide, solution <strong>G </strong>that were (2 marks)</em></li>
<li><em>Determine;</em>
<ul>
<li><em>The number of moles of sulphuric acid in 0cm<sup>3</sup> of solution <strong>K.</strong></em></li>
</ul>
</li>
</ul>
<p>(1</p>
<p> ;</p>
<ul>
<li><em>The number of moles of sulphuric acid in 100cm<sup>3</sup> of solution K<strong>.</strong></em></li>
</ul>
<p>(1</p>
<p> ;</p>
<ul>
<li><em>Using the results from (d) and g (ii) above, calculate the total number of moles of sulphuric acid in 50cm<sup>3</sup> of solution </em></li>
</ul>
<p>(1 mark)</p>
<p> ;</p>
<ol start="2">
<li><em>You</em> <em>are</em> <em>provided</em> <em>with</em> <em>solid</em> <em>Carry</em> <em>out</em> <em>the</em> <em>tests</em> <em>below.</em> <em>Write</em> <em>your</em> <em>observations and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="50"><em>a).</em></td>
<td width="684"><em>Place all of solid <strong>L </strong>in a dry test-tube and heat it until it just turns reddish- yellow at the bottom. Test the gas with a glowing wooden splint. Keep the residue for tests in (b)</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="50"><em>b).</em></p>
<p><em>i).</em></td>
<td width="684"><em>Allow the residue from (a) above to cool for about three minutes. Add 5-6 drops of concentrated nitric acid, then add distilled water until the test-tube is three quarters full. Filter the mixture into a boiling tube then add more distilled water to the filtrate until the boiling tube is half-full. Shake well. Use the solution obtained for the tests below</em></p>
<p><em>Observations</em></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="50"><em>ii).</em></td>
<td width="684"><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>po</em><em>r</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>2</em><em>M</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m </em><em>hydroxide dropwise until in excess</em></p>
<p><em>Observations inferences</em></p>
<p><em>(3 marks)</em></td>
</tr>
<tr>
<td width="50"><em>iii).</em></td>
<td width="684"><em>T</em><em>o</em><em> another 2cm<sup>3</sup> of the solution in a test-tube, add aqueous ammonia dropwise until in excess</em></p>
<p><em>Observations Inference</em></p>
<p><em> </em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="50"><em>iv).</em></td>
<td width="684"><em>T</em><em>o</em> <em>a</em> <em>t</em><em>h</em><em>i</em><em>r</em><em>d</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em> <em>f</em><em>e</em><em>w drops of 2M sulphuric acid</em></p>
<p><em> </em></p>
<p><em>Observations Inferences</em></p>
<p><em>1mark 1 mark</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol start="3">
<li><em>Y</em><em>o</em><em>u</em> <em>a</em><em>r</em><em>e</em> <em>p</em><em>r</em><em>o</em><em>v</em><em>i</em><em>d</em><em>e</em><em>d</em> <em>wi</em><em>t</em><em>h</em> <em>a</em><em>n</em> <em>o</em><em>r</em><em>g</em><em>a</em><em>n</em><em>i</em><em>c</em> <em>c</em><em>o</em><em>m</em><em>pound</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <strong><em>M</em></strong><em>.</em> <em>C</em><em>a</em><em>rr</em><em>y</em> <em>o</em><em>u</em><em>t</em> <em>t</em><em>h</em><em>e</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>s</em> <em>below</em><em>. </em><em>Write your observations and inferences in the spaces provided</em></li>
</ol>
<p> ;</p>
<p>Place all solid M in a boiling tube. Add distilled water until the boiling tube is half- full. Shake the mixture thoroughly until all the solid dissolves. Use the solution for the tests below.</p>
<table>
<tbody>
<tr>
<td width="113"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER /NOVEMBER 1998</h2>
<h3>1. (20 marks) You are provided with:</h3>
<ul>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>M</em><em>,</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>N</em><em>,</em> <em>c</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>i</em><em>n</em><em>g</em> <em>8</em><em>.</em><em>8</em><em>g</em> <em>pe</em><em>r</em> <em>l</em><em>i</em><em>t</em><em>r</em><em>e</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>x</em><em>i</em><em>d</em><em>e</em></li>
<li><em>0</em><em>.</em><em>5</em><em>g</em> <em>o</em><em>f</em> <em>a</em><em>n</em> <em>i</em><em>m</em><em>pu</em><em>r</em><em>e</em> <em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>P</em></li>
</ul>
<p> ;</p>
<h3>You are required to determine the:</h3>
<p>a). Concentration of solution M in moles per litre b). Percentage purity of the carbonate, solid P.</p>
<p> ;</p>
<h3>Procedure I.</h3>
<p>Fill the burette with sodium hydroxide, solution N. Pipette 25.0cm<sup>3</sup> of hydrochloric acid, solution M into a conical flask. Add 2-3 drops of screened methyl orange indicator and titrate. (The colour of the indicator changes from pink to green) record your results in table I below. Repeat the titration two more times and complete the table.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="338"><em>Table</em></td>
<td width="150"><em>1</em></td>
<td width="143"><em>2</em></td>
<td width="152"><em>3</em></td>
</tr>
<tr>
<td width="338"><em>Final burette reading</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
<tr>
<td width="338"><em>Initial burette reading</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
<tr>
<td width="338"><em>Volume of solution N used (cm<sup>3</sup>)</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p> ;</p>
<p>What is the average volume of solution N used? (1 mark) Determine;</p>
<ul>
<li><em>T</em><em>h</em><em>e</em> <em>c</em><em>o</em><em>n</em><em>c</em><em>e</em><em>n</em><em>t</em><em>r</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>N</em> <em>i</em><em>n</em> <em>m</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>pe</em><em>r</em> <em>l</em><em>i</em><em>t</em><em>r</em><em>e</em><em>.</em> <em>(</em><em>N</em><em>a</em><em>=</em><em>23</em><em>.</em><em>0</em><em>,</em> <em>O</em><em>=</em><em>16</em><em>.</em><em>0</em><em>,</em> <em>H</em><em>=</em><em>1</em><em>.</em><em>0</em><em>)</em></li>
</ul>
<p>(1 mark)</p>
<ul>
<li><em>Concentration of solution M in moles per litre </em><em>(1</em> <em>mark)</em></li>
</ul>
<p> ;</p>
<h3>Procedure II</h3>
<p>Using a measuring cylinder, measure out 100cm<sup>3</sup> of solution M into a 250cm<sup>3</sup> beaker. Add all of solid P into the beaker containing solution M. Swirl the mixture and allow the reaction to proceed for about 4 minutes.</p>
<p>Label the solution with sodium hydroxide, solution N. Pipette 25.0cm<sup>3</sup> of solution Q into a conical flask. Add 2-3 drops of screened methyl orange indicator and titrate. Record your results in table II below. Repeat the titration two more times and complete the table.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="338"><em>Table II</em></td>
<td width="150"><em>1</em></td>
<td width="143"><em>2</em></td>
<td width="152"><em>3</em></td>
</tr>
<tr>
<td width="338"><em>Final burette reading</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
<tr>
<td width="338"><em>Initial burette reading</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
<tr>
<td width="338"><em>Volume of solution N (cm<sup>3</sup>)</em></td>
<td width="150"> ;</td>
<td width="143"> ;</td>
<td width="152"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p>What is the average volume of solution N Used? a). Calculate the:</p>
<p>i). Moles of hydrochloric acid in 25.0cm<sup>3</sup> of solution Q (2 marks) ii). Moles of hydrochloric acid in 100cm<sup>3</sup> of solution Q (1 mark) iii). Moles of hydrochloric acid in 100cm<sup>3</sup> of the original hydrochloric</p>
<p>acid solution M. (1mark)</p>
<ul>
<li><em>Moles of hydrochloric acid that were used up in the reaction with </em><em>solid (1 mark)</em></li>
<li><em>Moles of the carbonate that reacted with hydrochloric acid</em></li>
</ul>
<p>(1 mark)</p>
<p>b). Given that the relative formula mass of the carbonate is 72, calculate the; i). Mass of the carbonate that reacted (1 mark)</p>
<p>ii). Percentage purity of the carbonate, solid P (1 mark)</p>
<p> ;</p>
<h3>2. (12 marks)</h3>
<p>You are provided with solid S. Carry out the tests below and record your observations and inferences in the spaces provided.</p>
<ul>
<li><em>Place about one third of solid S in a dry test-tube. Heat the solid gently and then Test any gases produced with red and blue litmus papers.</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>Dissolve the remaining portion of solid S in 8cm<sup>3</sup> of distilled Divide </em><em>the solution into four portions.</em>
<ul>
<li><em>To the first portion, add aqueous sodium hydroxide dropwise until</em></li>
</ul>
</li>
</ul>
<table>
<tbody>
<tr>
<td width="74"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p>in excess</p>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (2 marks)</p>
<ul>
<li><em>To</em> <em>the</em> <em>second</em> <em>portion,</em> <em>add</em> <em>aqueous</em> <em>ammonia</em> <em>dropwise until in excess</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To the third portion, add 10cm<sup>3</sup> of barium chloride </em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To the fourth portion, add 1 cm<sup>3</sup> of lead (II) nitrate </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<h3>3. (8 marks)</h3>
<p>You are provided with solid L. Carry out the tests below and record your observations and inferences in the spaces provided.</p>
<ol>
<li><em>Place about half of solid L in a dry test-tube and heat it strongly. Test any </em><em>gases produced with red and blue litmus papers and also with a burning </em></li>
</ol>
<p>Observations Inferences</p>
<p> ;</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ol>
<li><em>Place the rest of solid L in a boiling tube and add about 10cm<sup>3</sup> of distilled </em><em> Shake well to dissolve all the solid.</em>
<ul>
<li><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>3</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>u</em><em>n</em><em>i</em><em>v</em><em>e</em><em>r</em><em>s</em><em>a</em><em>l</em> <em>i</em><em>nd</em><em>i</em><em>c</em><em>a</em><em>t</em><em>o</em><em>r </em><em>solution and find its pH</em></li>
</ul>
</li>
</ol>
<table>
<tbody>
<tr>
<td width="221"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<ul>
<li><em>T</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>r</em><em>e</em><em>s</em><em>t</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>bou</em><em>t</em> <em>5</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>2</em><em>M</em> <em>d</em><em>i</em><em>l</em><em>u</em><em>t</em><em>e </em><em>hydrochloric acid Filter the mixture and retain the residue </em><em>for test(c) below.</em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark)</p>
<p> ;</p>
<ul>
<li><em>Transfer the residue from b (ii) above into a boiling Add about 10cm<sup>3</sup> of distilled water. Warm the mixture and add a little solid sodium </em><em>carbonate</em></li>
</ul>
<p>Observations Inferences</p>
<table>
<tbody>
<tr>
<td colspan="2" width="502"> ;</td>
<td width="338"> ;</td>
</tr>
<tr>
<td width="83"><em>37</em></td>
<td width="419"><em>Chemistry Practical Study Pack 1989 &#8211; 201</em></td>
<td rowspan="2" width="338"><em>6</em></td>
</tr>
<tr>
<td colspan="2" width="502"> ;</td>
</tr>
<tr>
<td width="71"></td>
<td width="357"></td>
<td width="266"></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 1999</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>Solution</em> <strong><em>E </em></strong><em>099M hydrochloric acid</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <strong><em>F</em></strong> <em>c</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>i</em><em>n</em><em>g</em> <em>15</em><em>.</em><em>3</em><em>g</em> <em>pe</em><em>r</em> <em>l</em><em>i</em><em>t</em><em>r</em><em>e</em> <em>o</em><em>f</em> <em>a</em> <em>ba</em><em>s</em><em>i</em><em>c</em> <em>c</em><em>o</em><em>m</em><em>pound</em><em>,</em></li>
<li><em>G</em><em>2</em><em>X</em><em>10</em><em>H</em><em>2</em> <em>O</em><em>→</em><em>14</em><em>.</em><em>3</em><em>gN</em><em>a</em><em>2</em><em>C</em><em>O</em><em>3</em><em>10</em><em>H</em><em>2</em><em>O</em></li>
</ul>
<h3>You are required to determine the relative atomic mass of G. Procedure:</h3>
<p>Place solution <strong>E </strong>in a burette.</p>
<p>Pipette 25cm<sup>3</sup> of solution <strong>F </strong>into a 250cm<sup>3</sup> conical flask. Add two drops of methyl orange indicator and titrate. Record your results in the table below. Repeat the procedure two more times and complete table I.</p>
<p> ;</p>
<ul>
<li><em>i).</em></li>
</ul>
<table>
<tbody>
<tr>
<td width="330"> ;</td>
<td width="75"><em>I</em></td>
<td width="90"><em>II</em></td>
<td width="90"><em>III</em></td>
</tr>
<tr>
<td width="330"><em>Final burette reading</em></td>
<td width="75"> ;</td>
<td width="90"> ;</td>
<td width="90"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial burette reading</em></td>
<td width="75"> ;</td>
<td width="90"> ;</td>
<td width="90"> ;</td>
</tr>
<tr>
<td width="330"><em>Volume of solution E used (cm<sup>3</sup>)</em></td>
<td width="75"> ;</td>
<td width="90"> ;</td>
<td width="90"> ;</td>
</tr>
</tbody>
</table>
<p>(3 marks)</p>
<h3>Table I</h3>
<p>ii). What is the average volume of solution <strong>E</strong>?</p>
<p> ;</p>
<ul>
<li><em>Given that one mole of <strong>F </strong>reacts with 2 moles of <strong>E</strong>. Calculate the:</em>
<ul>
<li><em>N</em><em>u</em><em>m</em><em>be</em><em>r</em><em> of moles of the basic compound, G</em><em>2</em><em>X</em><em>.</em><em>10</em><em>H</em><em>2</em><em>O</em><em> in the volume of </em><em>solution F </em></li>
<li><em>Concentration of solution F in moles per </em></li>
<li><em>R</em><em>e</em><em>l</em><em>a</em><em>t</em><em>i</em><em>v</em><em>e</em><em>f</em><em>o</em><em>r</em><em>m</em><em>u</em><em>l</em><em>a</em><em> </em><em>m</em><em>a</em><em>ss</em><em> </em><em>o</em><em>f</em><em> </em><em>t</em><em>h</em><em>e</em><em> </em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>c</em><em>o</em><em>m</em><em>pound</em><em>,</em><em> </em><em>G</em><em>2</em><em>X</em><em>10</em><em>H</em><em>2</em><em>O</em><em>.</em></li>
<li><em>Relative atomic mass of (relative formula masses of X= 60 atomic masses of H=10, O=16.0)</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>2. You are provided with:</h3>
<ul>
<li><em>Magnesium ribbon labeled solid <strong>K</strong></em></li>
<li><em>0M hydrochloric acid labeled solution <strong>L</strong></em></li>
<li><em>Stop clock /watch</em></li>
</ul>
<p> ;</p>
<p>You are required to determine the rate of reaction between magnesium and hydrochloric acid at different concentrations</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>Procedure.</h3>
<ol>
<li><em>Place the</em> <em>five test tube on the test tube rack and label them 1,2,3,4,and 5. Using </em><em>a</em> <em>10</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>m</em><em>e</em><em>a</em><em>s</em><em>u</em><em>r</em><em>i</em><em>n</em><em>g</em><em> cylinder ,measure out the volumes of 2.0M hydrochloric acid shown, solution <strong>L </strong>as shown in table II and pour them into the corresponding test tube. Wash the measuring cylinder and use it to measure the volumes of water as indicated in the table and pour into the corresponding test </em></li>
<li><em>Cut</em> <em>out</em> <em>five</em> <em>pieces</em> <em>each</em> <em>of</em> <em>exactly</em> <em>1cm</em> <em>length</em> <em>of</em> <em>magnesium</em></li>
<li><em>Transfer all the solution in the test tube 1 into a clean 100cm<sup>3</sup> Place one piece of magnesium into the beaker and start a stop clock/watch immediately. Swirl the beaker continuously ensuring that the magnesium is always inside the solution. Record in the table the time taken for the magnesium ribbon to disappear. Wash the beaker each time.</em></li>
</ol>
<p> ;</p>
<ol start="4">
<li><em>Repeat procedure III for each of the solutions in the test-tube 2, 3, 4 and 5 and complete the </em></li>
</ol>
<p>a).</p>
<table>
<tbody>
<tr>
<td width="360"><em>Test-tube Number</em></td>
<td width="60"><em>1</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>3</em></td>
<td width="60"><em>4</em></td>
<td width="69"><em>5</em></td>
</tr>
<tr>
<td width="360"><em>Volume of solution L (cm<sup>3</sup>)</em></td>
<td width="60"><em>10</em></td>
<td width="60"><em>9</em></td>
<td width="60"><em>8</em></td>
<td width="60"><em>7</em></td>
<td width="69"><em>6</em></td>
</tr>
<tr>
<td width="360"><em>Volume</em> <em>of</em> <em>water</em> <em>(cm<sup>3</sup>)</em></td>
<td width="60"><em>0</em></td>
<td width="60"><em>1</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>3</em></td>
<td width="69"><em>4</em></td>
</tr>
<tr>
<td width="360"><em>Time taken (sec)</em></td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="69"> ;</td>
</tr>
<tr>
<td width="360"><em>Rate of reaction = <sup>1</sup>/</em><em>time</em></td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="69"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<h3>Table II</h3>
<p>b). i). Plot a graph of rate of reaction <sup>1</sup>/time (y-axis) against volume of solution L (3 marks)</p>
<ul>
<li><em>Use the graph to determine the time that would be taken for a 1cm length of magnesium ribbon to disappear if the volume of the acid was 5cm<sup>3</sup> (2 marks)</em></li>
<li><em>I</em><em>n</em> <em>t</em><em>e</em><em>r</em><em>m</em><em>s</em> <em>o</em><em>f</em> <em>r</em><em>a</em><em>t</em><em>e</em> <em>o</em><em>f</em> <em>r</em><em>e</em><em>a</em><em>c</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>e</em><em>x</em><em>plai</em><em>n</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>h</em><em>a</em><em>p</em><em>e</em> <em>o</em><em>f</em> <em>y</em><em>o</em><em>u</em><em>r</em> <em>g</em><em>r</em><em>a</em><em>ph</em><em>.</em></li>
</ul>
<p>(1 ½ marks)</p>
<ol start="3">
<li><em>You are provided with solid H. Carry out the tests below and write your observation an d inferences in the spaces </em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Place about half of the solid H in a clean dry test tube. Heat the </em><em>solid</em> <em>gently</em> <em>and</em> <em>then</em> <em>Test</em> <em>for</em> <em>any gas produced using both blue and red litmus papers</em></li>
</ul>
<p>Observations Inferences</p>
<p>(4½ marks)</p>
<ul>
<li><em>Dissolve the remaining portion of Solid H in about 8cm<sup>3</sup> of distilled water contained in a boiling tube. Divide the solution into three </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p>i). To the first portion ,add aqueous sodium hydroxide drop wise until in excess.</p>
<p>Observations Inferences</p>
<p>(2½ marks) ii). To the second portion, add two drops of concentrated nitric acid</p>
<p>then add aqueous sodium hydroxide drop wise until in excess Observations Inferences</p>
<p> ;</p>
<p>(1½ marks) iii). I. To the third portion, add 2-3 drops of barium chloride solution</p>
<p>Observations Inferences</p>
<p>(1½ marks)</p>
<ol>
<li>To the mixture obtained in (iii) I above, add about 2cm<sup>3</sup> of 2M aqueous hydrochloric acid.</li>
</ol>
<p>Observations Inferences</p>
<p> ;</p>
<p>(2 marks)</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2000</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>Solution <strong>L </strong>containing 6g per litre of anhydrous sodium carbonate</em></li>
<li><em>Solution <strong>M</strong>: Hydrochloric acid</em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>Methyl orange indicator</em></li>
</ul>
<p>You are required to standardize the hydrochloric acid, solution <strong>M</strong>. <strong>Procedure</strong></p>
<p>Fill the burette with solution <strong>M</strong>. Pipette 25cm<sup>3</sup> of solution <strong>L </strong>into a conical flask. Add</p>
<p>three drops of phenolphthalein indicator and titrate with solution M. Record the readings</p>
<p> ;</p>
<p>in <strong>table I </strong>below. Add 3 drops of methyl orange indicator to the contents of the conical flask and continue titrating with solution M. Record the readings in <strong>table II </strong>below. Repeat the procedure and complete <strong>tables I </strong>and <strong>II</strong>.</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p>a). i). <strong>Table I </strong>(Using phenolphthalein indicator)</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="233"> ;</td>
<td width="180"><em>1</em><em>st</em></td>
<td width="257"><em>2</em><em>nd</em></td>
</tr>
<tr>
<td width="233"><em>Final burette reading</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
<tr>
<td width="233"><em>Initial burette reading</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
<tr>
<td width="233"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
</tbody>
</table>
<p>(3 marks)</p>
<p> ;</p>
<p>Find average titre t1 (½ mark)</p>
<p><em>…………………………………………………………………..</em></p>
<p> ;</p>
<p><strong><em>Table II </em></strong><em>(Using methyl orange indicator)</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="233"> ;</td>
<td width="180"><em>1</em><em>st</em></td>
<td width="257"><em>2</em><em>nd</em></td>
</tr>
<tr>
<td width="233"><em>Final burette reading</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
<tr>
<td width="233"><em>Initial burette reading</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
<tr>
<td width="233"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="180"> ;</td>
<td width="257"> ;</td>
</tr>
</tbody>
</table>
<p>(3 marks)</p>
<p>Find average titre t2 (½ mark)</p>
<p><em>……………………………………………………………………..</em></p>
<p> ;</p>
<ul>
<li><em>Total volume of solution M used = t</em><em>1 </em><em>+ t</em><em>2 </em><em>= ………………………….</em></li>
</ul>
<p>(1 mark)</p>
<p> ;</p>
<ul>
<li><em>Calculate</em> <em>the:</em>
<ul>
<li><em>Concentration of sodium carbonate in moles per litre (Relative formula mass of Na</em><em>2</em><em>CO</em><em>3 </em><em>= 106) (2marks)</em></li>
<li><em>Moles of sodium carbonate in 25cm<sup>3</sup> of solution (1 mark)</em></li>
<li><em>Moles of hydrochloric acid in the total volume of solution M used.</em></li>
</ul>
</li>
</ul>
<p>(1</p>
<p>mark)</p>
<ul>
<li><em>Concentration of hydrochloric acid in moles per </em><em>(2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>You are provided with 0g of Potassium nitrate labeled solid <strong>G</strong>. You are required to determine the enthalpy of solution of solid <strong>G</strong>.</em></li>
</ol>
<p> ;</p>
<h3>Procedure</h3>
<p>Using a measuring cylinder, place 30cm<sup>3</sup> of distilled water into a 100cm<sup>3</sup> beaker. Stir the</p>
<p> ;</p>
<p>water gently with a thermometer and take its temperature after every half minute. Record the readings in table III below. At exactly two minutes, add all solid <strong>G </strong>to the water at once. Stir well and take the temperature of the mixture after every half minute up to the fourth minute</p>
<p> ;</p>
<p><em>Record your results in <strong>table III.</strong></em></p>
<p><strong><em>Table III </em></strong><em>a).</em></p>
<table>
<tbody>
<tr>
<td width="189"><em>Time (min)</em></td>
<td width="45"><em>0</em></td>
<td width="53"><em>½</em></td>
<td width="60"><em>1</em></td>
<td width="60"><em>1 ½</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>2 ½</em></td>
<td width="54"><em>3</em></td>
<td width="68"><em>3 ½</em></td>
<td width="67"><em>4</em></td>
</tr>
<tr>
<td width="189"><em>Temperature (<sup>0</sup>C)</em></td>
<td width="45"> ;</td>
<td width="53"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="54"> ;</td>
<td width="68"> ;</td>
<td width="67"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<p>(3marks) b). On the grid provided, plot a graph of time against temperature</p>
<ul>
<li><em>O</em><em>n</em> <em>t</em><em>h</em><em>e</em> <em>g</em><em>r</em><em>a</em><em>ph</em><em>,</em> <em>s</em><em>h</em><em>o</em><em>w the change in temperature, âT (1 mark) Calculate:</em>
<ul>
<li><em>The </em><em>number of moles of solid G used in the experiment. (K=39.0, N=14.0, O=16.0) (1 mark)</em></li>
<li><em>T</em><em>h</em><em>e</em><em>e</em><em>n</em><em>t</em><em>h</em><em>a</em><em>l</em><em>p</em><em>y</em><em> </em><em>o</em><em>f</em><em> </em><em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em><em> </em><em>â</em><em>H</em><em>s</em><em>o</em><em>l</em><em>n</em> <em>a</em><em>n</em><em>d</em><em> </em><em>s</em><em>h</em><em>o</em><em>w the sign of âH</em><em>s</em><em>o</em><em>l</em><em>n </em><em>(Assume density of solution = 0g/cm<sup>3</sup></em></li>
</ul>
</li>
</ul>
<p>Specific heat capacity of solution = 4.2jg<sup>-1</sup> k<sup>-1</sup>) (3 marks)</p>
<p> ;</p>
<ol start="3">
<li><em>You are provided with 10 cm<sup>3</sup> of solution <strong>P </strong>in a conical Solution <strong>P </strong>contains two cations and one anion. Carry out the test below and record your observations and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Add 20cm<sup>3</sup> of 2M aqueous sodium hydroxide to all solution <strong>P </strong></em></li>
</ul>
<p>Shake well. Filter the mixture into a conical flask. Retain both the filtrate and the residue.</p>
<p>Observations Inferences</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>i). To about 2cm<sup>3</sup> of the filtrate, add 2M nitric acid dropwise until in excess (i.e. about 1cm<sup>3</sup> of the acid). Retain the </em></li>
</ul>
<p> ;</p>
<p>Observations Inferences</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<p>Divide the mixture in (b) (i) above into two portions</p>
<ul>
<li><em>To the first portion, add aqueous sodium hydroxide dropwise until </em><em>in excess</em></li>
</ul>
<p>Observations Inferences</p>
<p>(2 marks) (2 marks)</p>
<p> ;</p>
<ul>
<li><em>To</em> <em>the</em> <em>second</em> <em>portion,</em> <em>add</em> <em>aqueous</em> <em>ammonia</em> <em>dropwise</em> <em>until</em> <em>the excess (i.e. about 5cm<sup>3</sup> of aqueous ammonia)</em></li>
</ul>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To 2cm<sup>3</sup> of the filtrate, add 3 drops of 2M hydrochloric </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To 2cm<sup>3</sup> of the filtrate, add 3 drops of acidified chloride </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>r</em><em>e</em><em>s</em><em>i</em><em>d</em><em>u</em><em>e</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>bou</em><em>t</em> <em>5</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>d</em><em>i</em><em>l</em><em>u</em><em>t</em><em>e</em> <em>n</em><em>i</em><em>t</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em> <em>a</em><em>n</em><em>d</em> <em>a</em><em>ll</em><em>o</em><em>w it to filter into a test-tube. To 2cm<sup>3</sup> of this filtrate, add aqueous ammonia dropwise</em></li>
</ul>
<p>until in the excess then filter into a clean test-tube.</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2001</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>Sodium hydroxide labeled solution <strong>A</strong></em></li>
<li><em>128M hydrochloric acid labeled solution <strong>B</strong>.</em></li>
<li><em>Carboxylic acid labeled solution <strong>C</strong>.</em></li>
</ul>
<p> ;</p>
<p>Solution <strong>D </strong>prepared by diluting 25cm<sup>3</sup> of solution A with distilled water to 150cm<sup>3</sup> of solution. You are required to:</p>
<ul>
<li><em>Standardise solution <strong>D </strong>with solution <strong>B </strong></em><em>b). Determine the:</em>
<ul>
<li><em>Reaction ratio between sodium hydroxide, solution A and the carboxylic acid solution <strong>C</strong></em></li>
<li><em>Concentration of solution <strong>C </strong>in moles per </em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>Procedure I</h3>
<p>Fill a burette with solution B. Pipette 25cm<sup>3</sup> of solution D into a 250cm<sup>3</sup> conical flask. Add 2 drops of phenolphthalein indicator and titrate with solution <strong>B</strong>. Record your results in table 1. Repeat the titration two more times and complete the table.</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="323"> ;</td>
<td width="158"><em>I</em></td>
<td width="128"><em>II</em></td>
<td width="145"><em>III</em></td>
</tr>
<tr>
<td width="323"><em>Final burette reading</em></td>
<td width="158"> ;</td>
<td width="128"> ;</td>
<td width="145"> ;</td>
</tr>
<tr>
<td width="323"><em>Initial burette reading</em></td>
<td width="158"> ;</td>
<td width="128"> ;</td>
<td width="145"> ;</td>
</tr>
<tr>
<td width="323"><em>Volume of solution B used (cm<sup>3</sup>)</em></td>
<td width="158"> ;</td>
<td width="128"> ;</td>
<td width="145"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<p>(4 marks)</p>
<p> ;</p>
<ul>
<li><em>Determine</em> <em>the</em> <em>average</em> <em>volume</em> <em>of</em> <em>the</em> <em>solution</em> <em>B used (1 mark) b). Calculate the concentration in moles per litre of sodium hydroxide in:</em>
<ul>
<li><em>solution <strong>D </strong>(2 marks)</em></li>
<li><em>solution <strong>A </strong>(1 mark)</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>Procedure II</h3>
<p>Using a clean burette, place 16cm<sup>3</sup> of solution <strong>C </strong>into a boiling tube. Take the initial temperature of the solution in the boiling tube and record it in table II. Using a clean measuring cylinder, measure 4cm<sup>3</sup> of solution A into 100cm<sup>3</sup> beaker and add it to a solution <strong>C </strong>in the boiling tube. Stir the mixture immediately with a thermometer and record in table II the maximum (final) temperature reached. Repeat the experiment with the other sets of volumes of <strong>C </strong>and <strong>A </strong>in the table and complete it. (Rinse the thermometer and the boiling tube with distilled water after each experiment)</p>
<p> ;</p>
<h3>Table II</h3>
<table>
<tbody>
<tr>
<td width="375"><em>Volume of solution C(cm<sup>3</sup>)</em></td>
<td width="62"><em>16</em></td>
<td width="58"><em>12</em></td>
<td width="60"><em>8</em></td>
<td width="60"><em>6</em></td>
<td width="58"><em>4</em></td>
<td width="54"><em>2</em></td>
</tr>
<tr>
<td width="375"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="62"><em>4</em></td>
<td width="58"><em>8</em></td>
<td width="60"><em>12</em></td>
<td width="60"><em>14</em></td>
<td width="58"><em>16</em></td>
<td width="54"><em>18</em></td>
</tr>
<tr>
<td width="375"><em>Final temperature (<sup>O</sup>C)</em></td>
<td width="62"> ;</td>
<td width="58"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="58"> ;</td>
<td width="54"> ;</td>
</tr>
<tr>
<td width="375"><em>Initial</em> <em>temperature</em> <em>(<sup>0</sup>C)</em></td>
<td width="62"> ;</td>
<td width="58"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="58"> ;</td>
<td width="54"> ;</td>
</tr>
<tr>
<td width="375"><em>Change in temperature , (âT)</em></td>
<td width="62"> ;</td>
<td width="58"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="58"> ;</td>
<td width="54"> ;</td>
</tr>
</tbody>
</table>
<p>(6 marks)</p>
<p> ;</p>
<ul>
<li><em>On the grid provided ,plot a graph</em> <em>of âT (vertical axis)against the volume </em><em>o</em><em>f</em><em> sodium hydroxide ,solution <strong>A </strong>(3 marks)</em></li>
<li><em>F</em><em>r</em><em>o</em><em>m</em><em> the graph, determine the volume of sodium hydroxide solution a required to neutralize the carboxylic (1 mark)</em></li>
<li><em>C</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>c</em><em>a</em><em>r</em><em>bo</em><em>x</em><em>y</em><em>l</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em> <em>u</em><em>s</em><em>e</em><em>d</em> <em>f</em><em>o</em><em>r</em> <em>n</em><em>e</em><em>u</em><em>t</em><em>r</em><em>a</em><em>l</em><em>i</em><em>z</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em>.</em></li>
</ul>
<p>(1 mark)</p>
<ul>
<li><em>Calculate</em> <em>the:</em>
<ul>
<li><em>Ratio</em> <em>between</em> <em>the volumes of solutions <strong>A </strong>and (1 mark)</em></li>
<li><em>C</em><em>o</em><em>n</em><em>c</em><em>e</em><em>n</em><em>t</em><em>r</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em> in moles per litre of carboxylic acid, solution <strong>C. </strong>(assume that the volume ratio is the same as the mole ratio)</em></li>
</ul>
</li>
</ul>
<p>(2 marks)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="2">
<li><em>You are provided with solid <strong>E</strong>. carry out the tests below and record your observation and inference in the spaces </em></li>
</ol>
<p>Divide solid E into two halves.</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>You are provided with Solid <strong>F</strong>. carry out the tests below and record your observation and inferences in the spaces Place all the Solid <strong>F </strong>into a boiling tube. Add 10cm<sup>3</sup> of distilled water and shake well. Use 2cm<sup>3</sup> </em><em>portion of the mixture for the following reactions.</em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="669"><em>a). Test the first portion with both blue and red litmus papers </em><em>Observations Inferences</em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="669"><em>b). To the second portion, add three drops of bromine water </em><em>Observations Inferences</em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="669"><em>c). To the third portion, add 2 drops of acidified potassium </em><em>permanganate and shake well</em></p>
<p><em>Observations Inferences</em></p>
<p><em>(2 marks)</em></td>
</tr>
<tr>
<td width="669"><em>d). Warm the fourth portion slightly and add a little solid G, sodium </em><em>hydrogen carbonate</em></p>
<p><em>observations inferences</em></p>
<p><em>(2 marks)</em></td>
</tr>
</tbody>
</table>
<h2>OCTOBER / NOVEMBER 2002</h2>
<h3>1. You are provided with the following;</h3>
<ul>
<li><em>Hydrogen peroxide labeled solution A</em></li>
<li><em>Dilute sulphuric acid labeled solution B</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Sodium thiosulphate labeled solution C</em></li>
<li><em>Potassium iodide labeled solution D</em></li>
<li><em>Starch solution labeled solution E</em></li>
<li><em>Distilled water in a wash bottle</em></li>
</ul>
<p> ;</p>
<p>You are required to determine how the rate of reaction of hydrogen peroxide with potassium iodide varies with the concentration of hydrogen peroxide.</p>
<p> ;</p>
<h3>Procedure Experiment I.</h3>
<p>Label two 200ml or 250ml beakers as beaker 1 and beaker 2.</p>
<p>Using a burette, place 25.0cm<sup>3</sup> of solution A into beaker 1. Into the same beaker, add 20cm<sup>3</sup> of solution B using a 50ml or 100ml measuring cylinder. Shake the contents of beaker 1.</p>
<p> ;</p>
<p>Using a 10ml measuring cylinder, place 5cm<sup>3</sup> of solution C into beaker 2 followed by 5cm<sup>3</sup> of solution D then 2cm<sup>3</sup> of solution E. shake the contents of beaker 2. Pour the contents of beaker 2 into beaker 1 and start a stop clock/watch immediately. Swirl the mixture and let it stand. Note the time taken for the blue colour to appear. Record the time in the space provided for experiment 1 in the table below.</p>
<p> ;</p>
<p>Clean beaker 1. Repeat the procedure with the volumes of water below. Clean beaker 1. Repeat the procedure with the volumes of water, solutions A, B, C, D and E as shown in the table for experiments 2 to 5.</p>
<p>Complete the table by computing <u> 1 </u> sec <sup>-1</sup> 7 ½ marks)</p>
<p>Time</p>
<p>a).</p>
<table>
<tbody>
<tr>
<td width="102"> ;</td>
<td colspan="3" width="257"><strong><em>BEAKER 1</em></strong></td>
<td colspan="3" width="269"><strong><em>BEAKER 2</em></strong></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
<tr>
<td width="102"><em> </em></p>
<p><em> </em></p>
<p><em>Experiment</em></td>
<td width="72"><em>Volume of water (cm<sup>3</sup>)</em></td>
<td width="98"><em>Volume </em><em>of</em> <em>hydrogen peroxide, solution A (cm<sup>3</sup>)</em></td>
<td width="87"><em>Volume of dilute sulphuric acid, solution B</em></p>
<p><em>(cm<sup>3</sup>)</em></td>
<td width="105"><em>Volume of sodium thiosulphate, solution C (cm<sup>3</sup>)</em></td>
<td width="90"><em>Volume of potassium iodide, solution D (cm<sup>3</sup>)</em></td>
<td width="74"><em>Volume of starch, solution E (cm<sup>3</sup>)</em></td>
<td width="56"><em>Time (sec)</em></td>
<td width="98"><u> </u><em><u>1</u></em></p>
<p><em>Time sec <sup>-1</sup></em></td>
</tr>
<tr>
<td width="102"><em>1</em></td>
<td width="72"><em>0</em></td>
<td width="98"><em>25</em></td>
<td width="87"><em>20</em></td>
<td width="105"><em>5</em></td>
<td width="90"><em>5</em></td>
<td width="74"><em>2</em></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
<tr>
<td width="102"><em>2</em></td>
<td width="72"><em>5</em></td>
<td width="98"><em>20</em></td>
<td width="87"><em>20</em></td>
<td width="105"><em>5</em></td>
<td width="90"><em>5</em></td>
<td width="74"><em>2</em></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
<tr>
<td width="102"><em>3</em></td>
<td width="72"><em>10</em></td>
<td width="98"><em>15</em></td>
<td width="87"><em>20</em></td>
<td width="105"><em>5</em></td>
<td width="90"><em>5</em></td>
<td width="74"><em>2</em></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
<tr>
<td width="102"><em>4</em></td>
<td width="72"><em>15</em></td>
<td width="98"><em>10</em></td>
<td width="87"><em>20</em></td>
<td width="105"><em>5</em></td>
<td width="90"><em>5</em></td>
<td width="74"><em>2</em></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
<tr>
<td width="102"><em>5</em></td>
<td width="72"><em>20</em></td>
<td width="98"><em>5</em></td>
<td width="87"><em>20</em></td>
<td width="105"><em>5</em></td>
<td width="90"><em>5</em></td>
<td width="74"><em>2</em></td>
<td width="56"> ;</td>
<td width="98"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Plot a graph of (<sup>1</sup>/</em><em>time</em><em>) sec <sup>-1</sup> (y-axis) against volume of hydrogen peroxide </em><em>used</em> <em>(solution</em> <em>A). (4 marks)</em></li>
<li><em>From your graph determine the time that would be taken if the contents of </em><em>beaker</em> <em>1</em> <em>were</em> <em>5cm<sup>3</sup></em> <em>water</em> <em>7.5cm<sup>3</sup></em> <em>solution A and 20cm<sup>3</sup> solution B.</em></li>
</ul>
<p>(2 marks)</p>
<ul>
<li><em>How does the rate of reaction of hydrogen peroxide with potassium iodide vary with the concentration of hydrogen peroxide </em><em>(2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>You are provided with solution F, solid G and sodium sulphate Carry out the tests below. Write your observations and inferences in the spaces provided. </em><em>a). Place 10cm<sup>3</sup> of solution F in a boiling tube. Add all of solid G to solution F</em></li>
</ol>
<p>at once. Warm the mixture for one minute then shake vigorously for about five minutes. Filter the mixture into a test-tube and use the filtrate for tests</p>
<p>(b) to (e) below.</p>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>l</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>f</em><em>i</em><em>v</em><em>e</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>ba</em><em>r</em><em>i</em><em>u</em><em>m</em> <em>n</em><em>i</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e </em><em>solution</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>l</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>d</em><em>r</em><em>o</em><em>p wise of aqueous sodium hydroxide dropwise until in excess solution</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>l</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>f</em><em>i</em><em>v</em><em>e</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>2</em><em>M</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c </em><em>acid and warm the mixture to boiling</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 ½ marks) (1 mark)</p>
<ul>
<li></li>
</ul>
<table>
<tbody>
<tr>
<td width="179"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<ul>
<li>
<em>To the remaining filtrate, add 5cm<sup>3</sup> of the sodium sulphate solution provided then filter into a clean test-tube using a clean Retain the </em><em>filtrate for test (f) below.</em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To 2cm<sup>3</sup> of the filtrate obtained in (e) above, add aqueous ammonia </em><em>dropwise until in excess</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid Carry out the tests below. Write your observations </em><em>and inferences in the spaces provided.</em></li>
</ol>
<ul>
<li><em>Using a clean metallic spatula, heat about one third of solid H in a Bunsen burner </em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td colspan="2" rowspan="2" width="114"> ;</td>
<td width="315"><em>Observations</em></td>
<td width="369"><em>Inferences</em></td>
</tr>
<tr>
<td width="315"> ;</td>
<td width="369"> ;</td>
</tr>
<tr>
<td width="83"><em>47</em></td>
<td colspan="3" width="715"><em>Chemistry Practical Study Pack 1989 &#8211; 2016</em></td>
</tr>
<tr>
<td width="67"></td>
<td width="22"></td>
<td width="262"></td>
<td width="342"></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>Dissolve the remaining portion of solid H into about 10cm<sup>3</sup> of distilled </em><em>water and divide the solution into 3 </em>
<ul>
<li><em>To the first portion, add two drops of acidified potassium </em><em>permanganate solution</em></li>
</ul>
</li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To the second portion, add two drops of bromine water </em><em>Observations Inferences</em></li>
</ul>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>Determine the pH of the third portion using universal indicator </em><em>paper</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2003</h2>
<ol>
<li><em>You are provided with solution <strong>P </strong>and <strong>Q</strong>.</em>
<ul>
<li><em>Solution P is acidified potassium permanganate (the same solution will be used for question 3)</em></li>
<li><em>Solution Q was prepared by dissolving 18g of solid Q in distilled water to make 250cm<sup>3</sup> of solution.</em></li>
</ul>
</li>
</ol>
<p>You are required to determine the number of moles of Q that react with one mole of potassium permanganate.</p>
<p> ;</p>
<h3>Procedure</h3>
<p>Place the solution P in a burette. Pipette 25cm<sup>3</sup> of solution Q into a 250cm<sup>3</sup> conical flask. Titrate solution <strong>Q </strong>with solution P until a permanent pink colour just appears. Record your results in table I below. Repeat the above procedure two more times.</p>
<p> ;</p>
<p><em>a). <strong>Table I</strong></em></p>
<table>
<tbody>
<tr>
<td width="330"> ;</td>
<td width="120"><em>I</em></td>
<td width="120"><em>II</em></td>
<td width="99"><em>III</em></td>
</tr>
<tr>
<td width="330"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="120"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="120"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="330"><em>Volume of solution P (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="120"> ;</td>
<td width="99"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks) b). Calculate the average volume of solution <strong>P </strong>used. (1 mark)</p>
<ul>
<li><em>Gi</em><em>v</em><em>e</em><em>n</em> <em>t</em><em>h</em><em>a</em><em>t</em> <em>t</em><em>h</em><em>e</em> <em>c</em><em>o</em><em>n</em><em>c</em><em>e</em><em>n</em><em>t</em><em>r</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <strong><em>P</em></strong> <em>i</em><em>s</em> <em>0</em><em>.</em><em>02</em><em>M</em><em>,</em> <em>c</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>n</em><em>u</em><em>m</em><em>be</em><em>r</em> <em>o</em><em>f </em><em>moles of potassium permanganate (2 marks)</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Calculate the concentration of solution <strong>Q </strong>in moles per (Relative formula </em><em>mass of <strong>Q </strong>is 278) (2 marks)</em></li>
<li><em>Calculate the number of moles of <strong>Q</strong>:</em>
<ol start="25">
<li><em>In</em> <em>0cm<sup>3</sup></em> <em>of solution. (2 marks)</em></li>
<li><em>Which react with one mole of potassium permanganate?</em></li>
</ol>
</li>
</ul>
<p>(1 mark)</p>
<h3>2. You are provided with:</h3>
<ul>
<li><em>1</em><em>.</em><em>9</em><em>g</em><em>o</em><em>f</em><em> </em><em>s</em><em>o</em><em>l</em><em>i</em><em>d</em><em> </em><em>S</em><em>.</em><em> </em><em>s</em><em>o</em><em>l</em><em>i</em><em>d</em><em> </em><em>S</em><em> </em><em>i</em><em>s</em><em> </em><em>a</em><em> </em><em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em><em> </em><em>a</em><em>c</em><em>i</em><em>d</em><em>,</em><em> </em><em>H</em><em>2</em><em>A</em></li>
<li><em>5M solution of the dibasic acid H</em><em>2</em><em>A solution T</em></li>
<li><em>Sodium hydroxide, solution </em></li>
</ul>
<p> ;</p>
<p>You are required to determine:</p>
<ol>
<li><em>i) The molar heat of solution of solid </em></li>
<li>ii) The heat of reaction of one mole of the dibasic acid with sodium</li>
<li><em>Calculate the heat of reaction of solid H</em><em>2</em><em>A with aqueous sodium </em></li>
</ol>
<p> ;</p>
<h3>Procedure 1</h3>
<p>Place 30cm<sup>3</sup> of distilled water into a 100ml beaker. Measure the initial temperature of the water and record it in the table II below. Add the entire solid S at once. Stir the mixture carefully with the thermometer until all the solid dissolves. Measure the final temperature reached and record it in the table II.</p>
<p> ;</p>
<p><strong><em>Table II </em></strong><em>a).</em></p>
<table>
<tbody>
<tr>
<td width="330"><em>Final temperature(<sup>0</sup>C)</em></td>
<td width="255"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial</em> <em>temperature(<sup>0</sup>C)</em></td>
<td width="255"> ;</td>
</tr>
</tbody>
</table>
<p>(1½ marks) b). Determine the change in temperature, âT1 (½ mark)</p>
<h3>Calculate the:</h3>
<p>c). i). Heat change when H2A dissolves in water .assume the heat capacity of the solution is 4.2jg<sup>-1</sup>0c<sup>-1</sup> and density is 1g/cm<sup>3</sup> (2 marks)</p>
<ul>
<li><em>Number of moles of the acid that were (Relative formula mass of H</em><em>2</em><em>A is 126. (1 mark)</em></li>
<li><em>Molar</em><em>heat</em><em> </em><em>of</em><em> </em><em>solution</em><em> </em><em>H1</em><em> </em><em>solution</em><em> </em><em>of the acid H</em><em>2</em><em> (1 mark)</em></li>
</ul>
<p> ;</p>
<h3>Procedure II</h3>
<p>Place 30cm<sup>3</sup> of solution <strong>T </strong>into 100ml beaker. Measure the initial temperature and record</p>
<p>it in the Table III below. Measure 30cm<sup>3</sup> of sodium hydroxide, solution <strong>R</strong>. Add al the 30cm<sup>3</sup> of solution <strong>R </strong>at Once to the solution in the beaker.</p>
<p> ;</p>
<p>Stir the mixture with the thermometer. Measure the final temperature and record it in Table III.</p>
<p> ;</p>
<h3>TABLE III</h3>
<p> ;</p>
<p>a).</p>
<table>
<tbody>
<tr>
<td width="360"><em>Final temperature (<sup>O</sup>C)</em></td>
<td width="210"> ;</td>
</tr>
<tr>
<td width="360"><em>Initial</em> <em>temperature</em> <em>(<sup>O</sup>C)</em></td>
<td width="210"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Determine the change in temperature âT</em><em>2 </em><em>c). Determine the:</em>
<ol start="4">
<li><em>Heat change for the reaction (assume the heart capacity of the solution is 2jg<sup>-1</sup> <sup>0</sup>C<sup>-1</sup> and density is 1g/cm<sup>3</sup>) (2 marks)</em></li>
</ol>
</li>
<li><em>Number of moles of the acid H</em><em>2</em><em>A (1 mark)</em></li>
<li><em>Heat of reaction H</em><em>2 </em><em>of one mole of the acid H</em><em>2</em><em>A with sodium </em></li>
</ul>
<p>(1 mark)</p>
<p> ;</p>
<p>d). Given that</p>
<p><em>Water</em></p>
<p> ;</p>
<p><em>âH</em><em>1 </em><em>is the heat for the reaction H</em><em>2</em><em>A(s) 2H<sup>+</sup></em><em>(a(aq)</em><em>+A<sup>2-</sup></em><em>(aq)</em></p>
<p> ;</p>
<p><em>âH</em><em>2</em> <em>is</em><em> </em><em>the</em><em> </em><em>heat</em><em> </em><em>for</em><em> </em><em>the reaction 2H+</em><em>(aq) </em><em>+ 2OH</em><em>-(aq) </em><em>2H</em><em>2</em><em>O</em><em>(l) </em><em>Calculate âH</em><em>3 </em><em>for the reaction H</em><em>2</em><em>A(s)+2OH<sup>&#8211;</sup></em><em>(aq) </em><em>2H</em><em>2</em><em>O(l)=A</em><em>2-(aq)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid Carry out tests below. Write your observations and </em><em>inference in the Spaces provided.</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="131"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2004</h2>
<h3>1. You are provided with:</h3>
<ul>
<li><em>Magnesium ribbon, solid A</em></li>
<li><em>0</em><em>.</em><em>7</em><em>M</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>B</em></li>
<li><em>3M</em> <em>sodium</em> <em>hydroxide,</em> <em>solution</em> <em>C</em></li>
<li><em>Distilled </em></li>
</ul>
<p> ;</p>
<h3>You are required to determine the:</h3>
<p>i). Temperature change when magnesium reacts with excess hydrochloric acid. ii). Number of moles of hydrochloric acid that remain unreacted</p>
<ul>
<li><em>Number of moles of magnesium that reacted</em></li>
<li><em>Molar</em> <em>heat</em> <em>of</em> <em>reaction</em> <em>between</em> <em>magnesium</em> <em>and</em> <em>hydrochloric</em> <em>acid</em></li>
</ul>
<p> ;</p>
<h3>Procedure I</h3>
<p>Using a burette, measure 50cm<sup>3</sup> of solution <strong>B </strong>and place it in a 100 ml beaker. Measure the temperature of solution <strong>B </strong>in the 100ml beaker and record the value in table 1. Put the magnesium ribbon in the 50cm<sup>3</sup> of solution B in the 100ml beaker <strong>immediately</strong>, start a stop Clock or watch. Stir the mixture continuously with the thermometer making sure that the Magnesium ribbon remains inside the solution as it reacts. Measure the temperature after Every 30 seconds and record the values in table1. Continue stirring and measuring the temperature to complete table 1.</p>
<p> ;</p>
<p>Keep the resulting solution for use in procedure 2 <strong>Table 1</strong></p>
<p>(a)</p>
<table>
<tbody>
<tr>
<td width="231"><em>Time (sec)</em></td>
<td width="44"><em>0</em></td>
<td width="44"><em>30</em></td>
<td width="41"><em>60</em></td>
<td width="44"><em>90</em></td>
<td width="54"><em>120</em></td>
<td width="53"><em>150</em></td>
<td width="53"><em>180</em></td>
<td width="54"><em>210</em></td>
<td width="53"><em>240</em></td>
<td width="53"><em>270</em></td>
<td width="54"><em> </em></p>
<p><em>300</em></td>
</tr>
<tr>
<td width="231"><em>Temperature (<sup>0</sup>C)</em></td>
<td width="44"> ;</td>
<td width="44"> ;</td>
<td width="41"> ;</td>
<td width="44"> ;</td>
<td width="54"> ;</td>
<td width="53"> ;</td>
<td width="53"> ;</td>
<td width="54"> ;</td>
<td width="53"> ;</td>
<td width="53"> ;</td>
<td width="54"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks)</p>
<ul>
<li><em>Plot a graph of temperature (y-axis) against time on the grid provided</em></li>
</ul>
<p>(3 marks)</p>
<ul>
<li><em>O</em><em>n</em><em> the graph, show the maximum change in temperature, âT, and determine its Value of âT (1 mark)</em></li>
</ul>
<p> ;</p>
<h3>Procedure 2</h3>
<p>Transfer all the solution obtained in 1 into a 250ml. conical flask. Clean the burette and use it to place 50cm<sup>3</sup> of distilled water into the beaker used in procedure 1. Transfer al the 50cm<sup>3</sup> of water into the 250ml conical flask containing the solution from procedure1. Label this as solution <strong>D</strong>. empty the burette and fill it with solution <strong>C</strong>. Pipette 25cm<sup>3</sup> of solution <strong>D </strong>and place it into an empty 250ml conical flask. Add two drops of phenolphthalein indicator and titrate solution <strong>C </strong>against <strong>D</strong>. Record the results in table two. Repeat the titration of solution <strong>C </strong>against solution D and complete the table 2</p>
<p> ;</p>
<h3>b). Table 2</h3>
<table>
<tbody>
<tr>
<td width="330"> ;</td>
<td width="105"><em>I</em></td>
<td width="135"><em>II</em></td>
<td width="92"><em>III</em></td>
</tr>
<tr>
<td width="330"><em>Final burette reading</em></td>
<td width="105"> ;</td>
<td width="135"> ;</td>
<td width="92"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial burette reading</em></td>
<td width="105"> ;</td>
<td width="135"> ;</td>
<td width="92"> ;</td>
</tr>
<tr>
<td width="330"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="105"> ;</td>
<td width="135"> ;</td>
<td width="92"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p> ;</p>
<p>i). Calculate the average volume of solution <strong>C </strong>used (1 mark) ii). Calculate the number of moles of:</p>
<p>I 0.3M sodium hydroxide used (1 mark) II Hydrochloric acid in 25cm<sup>3</sup> of solution D (1 mark)</p>
<p>III Hydrochloric acid in 100cm<sup>3</sup> of solution D (1 mark) IV hydrochloric acid in 50cm<sup>3</sup> of solution B (1 mark) V hydrochloric acid that reacted with magnesium (1 mark) VI magnesium that reacted (2 marks)</p>
<p> ;</p>
<ul>
<li><em>Using your answer in VI above, determine the molar heat of reaction between magnesium and hydrochloric acid (assume the heat capacity of the solution is</em></li>
</ul>
<p>4.2 jg<sup>-1</sup>deg<sup>-1</sup> and density is 1.0g/cm<sup>3</sup></p>
<p> ;</p>
<p>2 a). You are provided with solution H, carry out the tests below. Record</p>
<p>your observation and inferences in the spaces provided. Place 3cm<sup>3</sup> of the solution H in the boiling tube. Add 12cm<sup>3</sup> of distilled water and shake.</p>
<p> ;</p>
<h3>Retain the remainder of solution H for use in 2(b).</h3>
<p><strong> </strong></p>
<ul>
<li><em>Use</em> <em>about</em> <em>2cm<sup>3</sup></em> <em>portions</em> <em>of</em> <em>diluted</em> <em>solution</em> <em>H</em> <em>for</em> <em>tests</em> <em>I and </em></li>
</ul>
<p> ;</p>
<ol>
<li><em>To the first portion ,add drop wise about 1cm<sup>3</sup> of sodium hydroxide</em></li>
</ol>
<p>Observations Inferences</p>
<p> ;</p>
<p>( 2 marks)</p>
<ol>
<li><em>To the second portion, add 2 to 3 drops of barium chloride </em><em>Solution</em></li>
</ol>
<p>Observations Inferences</p>
<p>(2 marks)</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>To 3cm<sup>3</sup> of the diluted solution <strong>H</strong>, add drop wise all the chlorine </em><em>water (source of chlorine) provided</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(2 marks)</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>t</em><em>h</em><em>e</em> <em>d</em><em>i</em><em>l</em><em>u</em><em>t</em><em>e</em><em>d</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>H</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>l</em><em>l</em> <em>t</em><em>h</em><em>e</em> <em>b</em><em>r</em><em>o</em><em>m</em><em>i</em><em>n</em><em>e</em> <em>wa</em><em>t</em><em>e</em><em>r</em> <em>(</em><em>s</em><em>o</em><em>u</em><em>r</em><em>c</em><em>e</em> <em>o</em><em>f </em><em>bromine) </em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>( 2 marks)</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>d</em><em>i</em><em>l</em><em>u</em><em>t</em><em>e</em><em>d</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>H</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>2</em> <em>o</em><em>r</em> <em>3</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>l</em><em>e</em><em>a</em><em>d</em> <em>(</em><em>II</em><em>)</em> <em>n</em><em>i</em><em>t</em><em>r</em><em>a</em><em>t</em><em>e </em><em>solution</em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(2 marks)</p>
<p> ;</p>
<p> ;</p>
<h3>b). You are provided with;</h3>
<ul>
<li><em>Solution</em> <strong><em>E</em></strong> <em>containing</em> <em>barium</em> <em>ions</em></li>
<li><em>Solution <strong>F </strong>containing potassium ions</em></li>
<li><em>Solution <strong>G </strong>containing sodium ions</em></li>
</ul>
<p> ;</p>
<p>Carry out the tests on solutions <strong>E</strong>, <strong>F, G </strong>and <strong>H </strong>in order to identify the cation present in the solution <strong>H.</strong></p>
<p><strong> </strong></p>
<h3>Procedure</h3>
<p>Clean one end of glass rod thoroughly. Dip the clean end of the glass rod in solution <strong>E</strong>.</p>
<p> ;</p>
<p>Remove the end and heat it in the non-luminous part of the Bunsen burner flame. Note the colour of the flame and record it in table 3. Allow the glass rod to cool for about two minutes. Repeat the procedure with solutions <strong>F</strong>, <strong>G </strong>and <strong>H </strong>complete the table 3.</p>
<p> ;</p>
<p><strong><em>Table 3 </em></strong><em>i).</em></p>
<table>
<tbody>
<tr>
<td width="195"><em>Solution</em></td>
<td width="474"><em>Colour of the flame</em></td>
</tr>
<tr>
<td width="195"><strong><em>E</em></strong></td>
<td width="474"> ;</td>
</tr>
<tr>
<td width="195"><strong><em>F</em></strong></td>
<td width="474"> ;</td>
</tr>
<tr>
<td width="195"><strong><em>G</em></strong></td>
<td width="474"> ;</td>
</tr>
<tr>
<td width="195"><strong><em>H</em></strong></td>
<td width="474"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Identify the cation present in solution</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2005</h2>
<p><strong> </strong></p>
<h3>1. You are provided with solid M in the test tube</h3>
<ul>
<li><em>You are required to determine the freezing point of solid </em></li>
</ul>
<p> ;</p>
<h3>Procedure</h3>
<p>Place 150cm<sup>3</sup> of tap water in a 200ml or 250ml, beaker. Heat the water to near boiling. Using a test tube holder, immerse the test tube containing solid M into hot water (ensure that half of the test tube is immersed in water) continue heating the water until the solid starts to melt. insert a thermometer into the liquid being formed in the test tube and note the temperature when <strong>all </strong>the solid has just melted. Record the temperatures in table 1. Remove the test tube from the water and <strong>immediately </strong>start the stopwatch clock /watch and record the temperature of the contents of the test tube after every half a minute and complete the table. Dip the thermometer into the hot bath to clean it then wipe it with tissue paper.</p>
<p> ;</p>
<h3>Table 1</h3>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="229"><em>Time (Min)</em></td>
<td width="45"><em>0</em></td>
<td width="51"><em>½</em></td>
<td width="45"><em>1</em></td>
<td width="66"><em>1 ½</em></td>
<td width="45"><em>2</em></td>
<td width="66"><em>2 ½</em></td>
<td width="45"><em>3</em></td>
<td width="71"><em>3 ½</em></td>
</tr>
<tr>
<td width="229"><em>Temperature (<sup>0</sup>C)</em></td>
<td width="45"> ;</td>
<td width="51"> ;</td>
<td width="45"> ;</td>
<td width="66"> ;</td>
<td width="45"> ;</td>
<td width="66"> ;</td>
<td width="45"> ;</td>
<td width="71"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>On the grid provided on page 3, plot a graph of time(Horizontal axis) against </em></li>
</ul>
<p> ;</p>
<ul>
<li><em>From the graph determine the freezing point of solid M </em><em>(1 mark)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>You are provided with:</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Sodium</em> <em>hydroxide</em> <em>solution Labeled K</em></li>
<li><em>Solution L, containing 60.0g of acid L per litre of solution</em></li>
</ul>
<p>You are required to determine the relative formula mass of acid L <strong>Procedure</strong></p>
<p>Using a burette, transfer 25.0cm<sup>3</sup> of solution <strong>K </strong>into a 100ml beaker. Measure the</p>
<p>temperature T1 of the solution <strong>K </strong>and record it in table 2. Pipette 25.0 cm<sup>3</sup> of solution <strong>L </strong>into another 100ml beaker. Measure the temperature T2, of solution <strong>L </strong>and record it in table two add all the solution <strong>K </strong>at once to solution <strong>L</strong>. Stir carefully with the thermometer. Measure the highest temperature, T3 of the mixture and record it in table 2. Repeat the procedure and complete table 2.</p>
<p> ;</p>
<h3>TABLE 2</h3>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="420"> ;</td>
<td width="165"><em>I</em></td>
<td width="144"><em>II</em></td>
</tr>
<tr>
<td width="420"><em>Initial temperature of solution K T</em><em>1</em><em>(<sup>0</sup>C)</em></td>
<td width="165"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="420"><em>Initial temperature of solution L t2(<sup>0</sup>C)</em></td>
<td width="165"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="420"><em>Highest temperature of mixture T3 (<sup>0</sup>C)</em></td>
<td width="165"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="420"><em>Average initial temperature (<sup>0</sup>C)</em></td>
<td width="165"> ;</td>
<td width="144"> ;</td>
</tr>
<tr>
<td width="420"><em>Change</em> <em>in</em> <em>temperature</em> <em>âT (<sup>0</sup>C)</em></td>
<td width="165"> ;</td>
<td width="144"> ;</td>
</tr>
</tbody>
</table>
<p>(5 marks)</p>
<h3>Calculate the</h3>
<ul>
<li><em>Average T value. </em><em>(1 mark)</em></li>
<li><em>Heat change for reaction</em></li>
</ul>
<p>(Assume density of solution is 1g/cm<sup>3</sup> and the specific heat capacity is 4.2jg<sup>-1</sup>K<sup>-1</sup>)</p>
<p>(2 marks)</p>
<ul>
<li><em>Number of moles of acid <strong>L </strong>used given that the heat change for the one mole of acid <strong>L </strong>reacting with sodium hydroxide solution is 4Kj.</em></li>
</ul>
<p>(2 marks)</p>
<ul>
<li><em>Concentration of acid <strong>L </strong>in moles per </em><em>(2 marks)</em></li>
<li><em>Relative formula mass of acid <strong>L </strong>(2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="3">
<li><em>(a) You are provided with solid <strong>N</strong>. Carry out the tests Write your observations and inferences in the spaces provided.</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="131"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p>b). You are provided with solid <strong>Q</strong>. Carry out the tests below. Write your observation and inferences in the spaces provided.</p>
<table>
<tbody>
<tr>
<td width="131"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2006</h2>
<ol>
<li><em>You are provided with:</em>
<ul>
<li><em>5g of solid A in a boiling tube</em></li>
<li><em>Solution B 06M acidified potassium manganate (VII)</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<h3>You are required to determine:</h3>
<ol>
<li><em>The solubility of solids A at different temperatures</em></li>
<li><em>The number of moles of water of crystallization in solid A</em></li>
</ol>
<p> ;</p>
<h3>Procedure</h3>
<ul>
<li><em>Using a burette add 4cm<sup>3</sup> of distilled water</em> <em>to solid <strong>A </strong>in the boiling tube . Heat </em><em>the mixture while stirring with the thermometer to about 70<sup>0</sup>c .When <strong>all </strong>the solid has dissolved allow the solution to cool while stirring with the Note the temperature at which crystals of solid A first appear. Record this temperature in table 1.</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Using the burette, add 2cm<sup>3</sup> of distilled water to the contents of the boiling tube warm the mixture while stirring with the thermometer until <strong>all </strong>the solid Allow the mixture to cool while stirring. Note and record the temperature at which crystals of solid <strong>A </strong>first appear.</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Repeat</em> <em>procedure</em> <em>(b) two more times and record the temperature in the table </em></li>
</ul>
<p><strong><em>Retain the contents of the boiling tube </em></strong><em>for use in the procedure (e).</em></p>
<p> ;</p>
<ul>
<li><em>i). Complete table 1 by calculating the solubility of solid <strong>A </strong>at the different The solubility of a substance is the mass of that</em></li>
</ul>
<p>substance that dissolves in 100cm<sup>3</sup> (100g) of water at a particular temperature.</p>
<h3>Table 1</h3>
<table>
<tbody>
<tr>
<td width="237"><em>Volume of water in the boiling tube (cm<sup>3</sup>)</em></td>
<td width="246"><em>Temperature at which</em></p>
<p><em>crystals of solid A first appear (<sup>0</sup>C)</em></td>
<td width="246"><em>Solubility of solid A (g/100 g water)</em></td>
</tr>
<tr>
<td width="237"><em>4</em></td>
<td width="246"> ;</td>
<td width="246"> ;</td>
</tr>
<tr>
<td width="237"><em>6</em></td>
<td width="246"> ;</td>
<td width="246"> ;</td>
</tr>
<tr>
<td width="237"><em>8</em></td>
<td width="246"> ;</td>
<td width="246"> ;</td>
</tr>
<tr>
<td width="237"><em>10</em></td>
<td width="246"> ;</td>
<td width="246"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>On the grid provided, plot a graph of solubility of solid A (vertical axis) against </em></li>
<li><em>Using your graph, determine the temperature at which 100g of solid <strong>A </strong>would dissolve in 100cm<sup>3</sup> of (1 mark)</em></li>
</ul>
<p> ;</p>
<ol>
<li>e) i). Transfer the contents of the boiling tube into a 250ml volumetric flask,</li>
</ol>
<p> ;</p>
<p>rinse both the boiling tube and the thermometer with distilled water and add to the volumetric flask. Add more distilled water to make up to the mark. Label this solution <strong>A</strong>. fill a burette with solution <strong>B</strong>. Using the</p>
<p>pipette and pipette filter, place 25.0cm<sup>3</sup> of solution A into a</p>
<p>conical flask. Warm the mixture to about 60<sup>0</sup>C. Titrate the hot solution <strong>A </strong>with solution</p>
<p>B until a permanent pink colour persists. Record your readings in table 2.</p>
<p><em>Repeat the titration two more times and complete the table2<strong>. (Retain the remaining solution B for use in question 3 (b) (i)</strong></em></p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="323"> ;</td>
<td width="127"><em>I</em></td>
<td width="151"><em>II</em></td>
<td width="137"><em>III</em></td>
</tr>
<tr>
<td width="323"><em>Final burette reading</em></td>
<td width="127"> ;</td>
<td width="151"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="323"><em>Initial burette reading</em></td>
<td width="127"> ;</td>
<td width="151"> ;</td>
<td width="137"> ;</td>
</tr>
<tr>
<td width="323"><em>Volume of solution B used (cm<sup>3</sup>)</em></td>
<td width="127"> ;</td>
<td width="151"> ;</td>
<td width="137"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>Calculate</em> <em>the:</em>
<ol>
<li><em>average volume of solution b used (1 mark)</em></li>
<li><em>Number of moles of potassium manganate (VII) used (1 mark)</em></li>
</ol>
</li>
</ul>
<ul>
<li><em>Number of moles of A in 25cm<sup>3</sup> of solution A given that 2 moles of potassium manganate (VII) react completely with 5 moles of A (1 mark)</em></li>
</ul>
<ol>
<li><em>Relative formula mass of A, </em><em>(1 mark)</em></li>
</ol>
<ul>
<li><em>The formula of <strong>A </strong>has the form <strong>D</strong>.XH</em><em>2</em><em> Determine the value of x in the formula </em><em>given that the relative mass of <strong>D </strong>is 90.0 and atomic masses of oxygen and hydrogen are 16.0 and 1.0 respectively. (2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>You are provided with the solid <strong>E</strong>. carry out tests Write your observations</em></li>
</ol>
<p>and inferences in the spaces provided.</p>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid </em></li>
</ol>
<p>Carry out the following tests and record your observation and inferences in the spaces provided.</p>
<table>
<tbody>
<tr>
<td width="131"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2007</h2>
<h3>1. You are provided with;</h3>
<ul>
<li><em>Aqueous sulphuric acid labeled solution A</em></li>
<li><em>Solution B containing 0 g per litre of sodium carbonate</em></li>
<li><em>An aqueous solution of substance C labeled solution </em></li>
</ul>
<p> ;</p>
<p><strong><em>You are required to determine the; </em></strong><em>Concentration of solution <strong>A</strong></em></p>
<p>Enthalpy of reaction between sulphuric acid and substance <strong>C</strong></p>
<p><strong> </strong></p>
<h3>A. Procedure</h3>
<p>Using a pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution <strong>A </strong>into a 250ml.</p>
<p> ;</p>
<p>volumetric flask. Add distilled water to make 250cm<sup>3</sup> of solution. Label this solution <strong>D</strong>.</p>
<p> ;</p>
<p>Place solution <strong>D </strong>in a burette. Clean the pipette and use it to place 25.0cm<sup>3</sup> of solution <strong>B </strong>into a conical flask. Add 2 drops of methyl orange indicator provided and titrate with solution <strong>D. </strong>record your results in table 1. Repeat the titration two more times and complete the table.</p>
<p> ;</p>
<p>Table 1</p>
<table>
<tbody>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution D used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
</tbody>
</table>
<p>(3 marks)</p>
<p>Calculate;</p>
<p>i). Average volume of solution <strong>D </strong>used (1 mark) ii). Concentration of sodium carbonate in solution <strong>B</strong></p>
<p>(Na=23; 0; O=16; 0, C= 12.0) (1 mark)</p>
<ul>
<li><em>Concentration of sulphuric acid in solution <strong>D </strong></em><em>(2 marks)</em></li>
<li><em>Concentration of sulphuric acid in solution <strong>A </strong></em><em>(1 mark)</em></li>
</ul>
<p> ;</p>
<h3>B. Procedure</h3>
<p>Label six test-tubes as 1, 2,3,4,5 and 6. Empty the burette and fill it with solution</p>
<ol>
<li>From the burette, place 2cm<sup>3</sup> of solution A into test-tube number 1. From the same burette, place 4 cm<sup>3</sup> of solution A in test-tube number 2. Repeat the process for test-tube numbers 3, 4, 5 and 6 as shown in table 2.</li>
</ol>
<p> ;</p>
<p>Clean the burette and fill it with solution <strong>C</strong>. From the burette, place 14cm<sup>3</sup> of solution <strong>C </strong>into a boiling tube. Measure the initial temperature of solution <strong>C </strong>to the nearest 0.5<sup>0</sup>C and record it table 2. Add the contest of test-tube number <strong>1 </strong>to the boiling tube containing solution <strong>C</strong>. stirs the mixture with the thermometer. Note and record the highest temperature reached in <strong>table 2</strong>. Repeat the process with the other volumes of solution C given in <strong>table 2 </strong>and complete the table.</p>
<p> ;</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="384"><em>Test-tube number</em></td>
<td width="60"><em>1</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>3</em></td>
<td width="60"><em>4</em></td>
<td width="60"><em>5</em></td>
<td width="54"><em>6</em></td>
</tr>
<tr>
<td width="384"><em>Volume of solution A(cm<sup>3</sup>)</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>4</em></td>
<td width="60"><em>6</em></td>
<td width="60"><em>8</em></td>
<td width="60"><em>10</em></td>
<td width="54"><em>12</em></td>
</tr>
<tr>
<td width="384"><em>Volume of solution C(cm<sup>3</sup>)</em></td>
<td width="60"><em>14</em></td>
<td width="60"><em>12</em></td>
<td width="60"><em>10</em></td>
<td width="60"><em>8</em></td>
<td width="60"><em>6</em></td>
<td width="54"><em>4</em></td>
</tr>
<tr>
<td width="384"><em>Initial temperature of solution C(<sup>0</sup>C)</em></td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="54"> ;</td>
</tr>
<tr>
<td width="384"><em>Highest temperature of solution C(<sup>0</sup>C)</em></td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="54"> ;</td>
</tr>
<tr>
<td width="384"><em>Change</em> <em>in</em> <em>temperature</em> <em>âT(<sup>0</sup>C)</em></td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="54"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>(6 marks)</p>
<ul>
<li><em>On the grid provided, draw a graph of âT (vertical axis) against volume of solution A used (3 marks)</em></li>
<li><em>F</em><em>r</em><em>o</em><em>m</em> <em>t</em><em>h</em><em>e</em> <em>g</em><em>r</em><em>a</em><em>ph</em><em>,</em> <em>d</em><em>e</em><em>t</em><em>e</em><em>r</em><em>m</em><em>i</em><em>n</em><em>e</em><em>;</em>
<ol>
<li><em>The</em> <em>maximum</em> <em>change</em> <em>in</em> <em>temperature </em><em>(1 mark)</em></li>
</ol>
</li>
</ul>
<p> ;</p>
<ol>
<li><em>The</em> <em>volume</em> <em>of</em> <em>solution</em> <em>A</em> <em>required </em><em>to give the maximum change in temperature (1 mark)</em></li>
</ol>
<ul>
<li><em>Calculate the;</em>
<ol>
<li><em>Number of moles of sulphuric acid required to give the maximum change in temperature (1 mark)</em></li>
<li><em>Molar enthalpy of reaction between sulphuric acid and substance C (in kilojoules per mole of sulphuric acid).</em></li>
</ol>
</li>
</ul>
<p>Assume the specific heat capacity of the solution is 4.2jg<sup>-1</sup> K<sup>-1</sup> and density of solution is 1.0 gcm<sup>-3</sup>. (2 marks)</p>
<p> ;</p>
<ol start="2">
<li><em>You</em> <em>are</em> <em>provided</em> <em>with</em> <em>solid</em> <em>Carry</em> <em>out</em> <em>the</em> <em>tests</em> <em>below.</em> <em>Write</em> <em>your</em> <em>observations</em> <em>and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"><em>a).</em></td>
<td width="654"><em>Place one half of solid E in a clean dry test-tube and heat it strongly. Test any gases produced with blue and red litmus papers.</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(2 marks) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>b).</em></td>
<td width="654"><em>Place the other half of solid E in a boiling tube. Add about 10cm<sup>3</sup> of</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>distilled water and shake until all the solid dissolves. (Use the solution</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>for tests (i), (ii), (iii) and (iv).</em></td>
</tr>
<tr>
<td width="45"><em>i).</em></td>
<td width="654"><em>Place two or three drops of the solution in a test-tube. Add 3cm<sup>3</sup> of</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>distilled water. Add two drops of universal indicator to the mixture</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>obtained and then determine the pH of the mixture</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>Observations inferences</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="654"><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>ii).</em></td>
<td width="654"><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>q</em><em>u</em><em>e</em><em>o</em><em>u</em><em>s</em> <em>a</em><em>mm</em><em>o</em><em>n</em><em>i</em><em>a</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>&#8211; </em><em>wise until in excess</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>iii).</em></td>
<td width="654"><em>T</em><em>o</em><em> 2cm<sup>3</sup> of the solution in a test-tube, add three or four drops of solution G (aqueous potassium iodide)</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>iv).</em></td>
<td width="654"><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>f</em><em>o</em><em>u</em><em>r</em> <em>o</em><em>r</em> <em>f</em><em>i</em><em>v</em><em>e</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f </em><em>barium nitrate solution. Shake the mixture then add about 1cm<sup>3</sup> of dilute nitric acid and allow the mixture to stand for about 2 minutes.</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol start="3">
<li><em>You are provided with liquid carry out the tests below. Record your observations and inferences in the spaces provided.</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="45"><em>a).</em></td>
<td width="654"><em>Place three or four drops of liquid F on watch glass. Ignite the liquid using a Bunsen burner</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>b).</em></td>
<td width="654"><em>T</em><em>o</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>l</em><em>i</em><em>q</em><em>u</em><em>i</em><em>d</em> <em>F</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>bou</em><em>t</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>d</em><em>i</em><em>s</em><em>t</em><em>i</em><em>ll</em><em>e</em><em>d</em> <em>wa</em><em>t</em><em>e</em><em>r</em> <em>a</em><em>n</em><em>d </em><em>shake thoroughly.</em></p>
<p><em>Observations inferences</em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>c).</em></td>
<td width="654"><em>T</em><em>o</em> <em>1</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>l</em><em>i</em><em>q</em><em>u</em><em>i</em><em>d</em> <em>F</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em> <em>s</em><em>m</em><em>a</em><em>l</em><em>l</em> <em>a</em><em>m</em><em>o</em><em>u</em><em>n</em><em>t</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m </em><em>carbonate</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>d).</em></td>
<td width="654"><em>T</em><em>o</em><em> 2cm<sup>3</sup> of liquid F in a test-tube, add about 1cm<sup>3</sup> of solution H (acidified potassium dichromate (VI). Warm the mixture gently and allow it to stand for about one minute of distilled water and shake thoroughly.</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2008</h2>
<ol>
<li><em>You are provided with:</em>
<ul>
<li><em>Solid A</em></li>
<li><em>M</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>B</em></li>
<li><em>1M sodium hydroxide</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<p>You are required to determine the enthalpy change âH, for the reaction between solid A and one mole of hydrochloric acid.</p>
<p> ;</p>
<h3>Procedure A</h3>
<p>Using a burette, place 20.0cm<sup>3</sup> of 2.0M hydrochloric acid, solution <strong>B </strong>in a 100ml. Beaker. Measure the temperature of the solution after every half-minute and record the values in table 1. At exactly 2 ½ minutes, add <strong>all </strong>of solid <strong>A </strong>to the acid. Stir the mixture gently with the thermometer. Measure the temperature of the mixture after every half-minute and record the values in table 1. <strong>(Retain the mixture for use in procedure B)</strong>.</p>
<p> ;</p>
<h3>Table 1.</h3>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="210"><em>Time (min)</em></td>
<td width="45"><em>0</em></td>
<td width="45"><em>½</em></td>
<td width="45"><em>1</em></td>
<td width="55"><em>1 ½</em></td>
<td width="45"><em>2</em></td>
<td width="45"><em>2</em></p>
<p><em>½</em></td>
<td width="45"><em>3</em></td>
<td width="55"><em>3 ½</em></td>
<td width="45"><em>4</em></td>
<td width="60"><em>4 ½</em></td>
<td width="47"><em>5</em></td>
</tr>
<tr>
<td width="210"><em>Tem (<sup>0</sup>C)</em></td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="55"> ;</td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="45"> ;</td>
<td width="55"> ;</td>
<td width="45"> ;</td>
<td width="60"> ;</td>
<td width="47"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p> ;</p>
<p>i). Plot a graph of temperature (Y= axis) against time (3 marks) ii). Using the graph, determine the change in temperature âT (1 mark)</p>
<p>iii). Calculate the heat change for the reaction (assume that the specific heat capacity of the mixture is 4.2jg<sup>-1</sup>K<sup>-1</sup> and the density of the mixture is 1g/cm<sup>3</sup> (2marks)</p>
<p> ;</p>
<h3>Procedure B</h3>
<p>Rinse the burette thoroughly and fill it with sodium hydroxide. Transfer <strong>all </strong>the contents of the 100ml. beaker used in procedure <strong>A </strong>into a 250ml. volumetric flask. Add distilled water to make up to the mark. Label this solution <strong>C</strong>. Using a pipette and a <strong>pipette filler</strong>, place indicator and titrate against sodium hydroxide. Record your results in table 2. Repeat titration two more times and complete table 2.</p>
<p> ;</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="270"> ;</td>
<td width="165"><em>I</em></td>
<td width="135"><em>II</em></td>
<td width="129"><em>III</em></td>
</tr>
<tr>
<td width="270"><em>Final burette reading</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="270"><em>Initial burette reading</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="270"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="135"> ;</td>
<td width="129"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>Calculate the:</p>
<ul>
<li><em>Average volume of sodium hydroxide used (1 mark) ii). The number of moles of</em>
<ol>
<li><em>Sodium hydroxide used (1 mark)</em></li>
<li><em>Hydroxide acid in 25cm<sup>3</sup> of solution <strong>C </strong>(1 mark)</em></li>
</ol>
</li>
</ul>
<ul>
<li><em>Hydrochloric acid in 250cm<sup>3</sup> of solution <strong>C </strong>(1 mark)</em></li>
</ul>
<ol start="20">
<li><em>Hydrochloric acid in 0cm<sup>3</sup> of solution <strong>B </strong>(1 mark)</em></li>
<li><em>Hydrochloric acid that reacted with solid <strong>A </strong></em><em>(1</em> <em>mark)</em></li>
</ol>
<p> ;</p>
<p>iii). Calculate the enthalpy of reaction between solid A and one mole of hydrochloric acid (show the sign âH) (2 marks)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="2">
<li><em>You are provided with solid <strong>D</strong>. Carry out the tests Write your observations </em><em>and inferences in the spaces provided.</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="137"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="68"> ;</td>
<td width="594"><em>until no further change occurs. Test any gases produced with both blue and red litmus papers. Allow the residue to cool and use it for test (b).</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(2 marks) (1 mark)</em></td>
</tr>
<tr>
<td width="68"><em>b).</em></td>
<td width="594"><em>Add about 10cm<sup>3</sup> of 2M hydrochloric acid to the residue and shake for about three minutes. <strong>Keep the mixture for test (c)</strong></em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="68"><em>c). i).</em></td>
<td width="594"><em>Place about 1cm<sup>3</sup> of the mixture in a test-tube and add aqueous ammonia dropwise until in excess</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="68"><em>ii).</em></td>
<td width="594"><em>To the rest of the mixture, add all of solid E provided and shake the mixture well.</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid F. Carry out the tests below. Write your observations </em><em>and inferences in the spaces provided</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="75"><em>a).</em></td>
<td width="624"><em>Place about one third of solid F on a metallic spatula and burn it using a Bunsen burner</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(</em> <em>½</em> <em>mark) </em><em>( ½ mark)</em></td>
</tr>
<tr>
<td width="75"><em>b).</em></td>
<td width="624"><em>Place the remaining of solid F in a test-tube. Add about 6cm<sup>3</sup> of distilled water and shake the mixture well. (Retain the mixture for use in test (c)</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="75"><em>c). i).</em></td>
<td width="624"><em>To about 2cm<sup>3</sup> of the mixture, add a small amount of solid sodium hydrogen carbonate</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="75"><em>ii).</em></td>
<td width="624"><em>To about 1cm<sup>3</sup> of the mixture, add 1cm<sup>3</sup> of acidified potassium</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="75"> ;</td>
<td width="624"><em>dichromate</em> <em>(VI) and warm</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
<tr>
<td width="75"><em>iii).</em></td>
<td width="624"><em>To about 2cm<sup>3</sup> of the mixture, add two drops of acidifies potassium manganate (VII)</em></p>
<p><em>Observations inferences</em></p>
<p><em> </em></p>
<p><em>(1 mark) (1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<h2>OCTOBER / NOVEMBER 2009</h2>
<h3>1. You are provided with;</h3>
<ul>
<li><em>Solid</em><em>A,</em><em> </em><em>a metal carbonate M</em><em>2</em><em>CO</em><em>3</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>B</em><em>,</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em> <em>f</em><em>o</em><em>r</em> <em>u</em><em>s</em><em>e</em> <em>i</em><em>n</em> <em>q</em><em>u</em><em>e</em><em>s</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>1</em> <em>a</em><em>n</em><em>d</em> <em>2</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>C</em> <em>0</em><em>.</em><em>3</em><em>M</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>x</em><em>i</em><em>d</em><em>e</em></li>
<li><em>Methyl orange indicator</em></li>
</ul>
<p> ;</p>
<h3>You are required to:</h3>
<p>Prepare a dilute solution of hydrochloric acid and determine its concentration Determine the solubility of solid A in water</p>
<p> ;</p>
<h3>Procedure I</h3>
<p><strong><em>Dry conical flask for use in step 4)</em></strong></p>
<p><strong> </strong></p>
<p><strong>Step 1 </strong>Place all of solid A in a 250ml dry beaker. Add 100cm<sup>3</sup> of distilled water to solid A in the beaker. Using a glass rod, stir the mixture thoroughly for about two minutes. Leave the mixture to stand and proceed with steps 2 and 3.</p>
<p> ;</p>
<p><strong>Step 2 </strong>Using a pipette filler, place 25.0cm<sup>3</sup> of solution B in a 250ml volumetric flask. Add about 200cm<sup>3</sup> of distilled water. Shake the mixture well and add distilled water to make up to the mark. Label this as solution D.</p>
<p> ;</p>
<p><strong>Step 3 </strong>Fill a burette with solution C. Using a pipette and pipette filler, place 25.0cm<sup>3</sup> of solution D into a 250ml conical flask. Add two drops of the indicator provided and titrate solution D with solution C. Record your results in table 1. Repeat the titration two more times and complete the table 1. Retain the remaining solution D for use in step 5.</p>
<p> ;</p>
<p><strong>Step 4 </strong>Filter the mixture obtained in step 1 using filter funnel into a dry conical flask. Lable the filtrate as solution</p>
<p> ;</p>
<p><strong>Step 5 </strong>Clean the burette and fill it with solution D. using a pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution A into a 250ml conical flask. Add two drops of the indicator provided and titrate solution with solution D. record your results in table 2. Repeat the titration two more times and complete table 2.</p>
<p> ;</p>
<h3>Table 1</h3>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="90"><em>III</em></td>
<td width="9"> ;</td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td colspan="2" width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td colspan="2" width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td colspan="2" width="99"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>Calculate;</em>
<ul>
<li><em>The average volume of solution C</em></li>
<li><em>Moles of sodium hydroxide in the average volume of solution C used</em></li>
<li><em>Moles of hydrochloric acid in 0cm<sup>3</sup> of solution D iv). The morality of hydrochloric acid, solution D</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="99"><em>III</em></td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution D used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>Calculate;</em></li>
<li><em>The average volume of solution D used</em></li>
<li><em>Moles</em> <em>of</em> <em>hydrochloric</em> <em>acid</em> <em>in</em> <em>the</em> <em>average</em> <em>volume</em> <em>of</em> <em>solution D used</em></li>
<li><em>M</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>m</em><em>e</em><em>t</em><em>a</em><em>l</em> <em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>A</em> <em>i</em><em>n</em> <em>25</em><em>.</em><em>0</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>A </em><em>i</em><em>v</em><em>)</em><em>.</em><em> The solubility of the metal carbonate, solid A in water</em></li>
</ul>
<p>(Relative formula mass of metal carbonate = 74, assume density of solution =1g/cm<sup>3</sup>)</p>
<ol start="2">
<li><em>You are provided with solid Carry out the following tests and write your observations and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Place</em> <em>about</em> <em>one-half</em> <em>of solid E in a dry test-tube. Heat it strongly and test any gas produced using hydrochloric acid, solution B on a glass rod.</em></li>
</ul>
<p> ;</p>
<p>Observations Inferences</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>Place the rest of solid E in a boiling Add about 10cm<sup>3</sup> if distilled water. Shake well and use 2cm<sup>3</sup> portions for each of the tests below.</em></li>
</ul>
<p> ;</p>
<p>i). To one portion, add aqueous ammonia dropwise until in excess</p>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p>ii¬). To a second portion, add about 1cm<sup>3</sup> of hydrochloric acid solution B.</p>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p>iii). To a third portion, add two drops of aqueous lead (II) nitrate and heat the mixture to boiling;</p>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ol start="3">
<li><em>You are provide with solid F. Carry out the following tests and record your </em><em>observations and inferences in the spaces </em></li>
</ol>
<ul>
<li><em>Place about one half of solid F in a dry test-tube. Retain the other half of solid F for use in (b). Add all of the absolute ethanol provided to solid F in </em><em>the test-tube. Shake the </em></li>
</ul>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<p>Divide the mixture into two portions</p>
<ul>
<li><em>Determine the </em><em>P</em><em>H of the first portion using universal indicator solution and</em></li>
</ul>
<p>PH chart.</p>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To</em> <em>the</em> <em>second</em> <em>portion,</em> <em>add</em> <em>one</em> <em>half</em> <em>of</em> <em>the</em> <em>solid</em> <em>sodium</em> <em>hydrogen</em> <em>carbonate </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>Place the remaining amount of solid F in a boiling tube. Add 10cm<sup>3</sup> of distilled water and Boil the mixture and divide it into three portions while still warm.</em>
<ul>
<li><em>To the first portion, add the remaining amount of solid sodium </em><em>hydrogen</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To the second portion, add three drops of acidified potassium</em></li>
</ul>
<p> ;</p>
<p>dichromate (VI) solution and warm</p>
<p> ;</p>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To the third portion, add five drops of bromine water </em><em>Observations Inferences</em></li>
</ul>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<h2>OCTOBER /NOVEMBER 2010</h2>
<h3>1. You are provided with;</h3>
<ul>
<li><em>Acid</em> <em>A</em> <em>labeled</em> <em>solution</em> <em>A</em></li>
<li><em>M</em> <em>sodium</em> <em>hydroxide</em> <em>solution</em> <em>labeled solution B</em></li>
<li><em>Solutions C containing 0 g per litre of an alkanoic acid</em></li>
</ul>
<p> ;</p>
<p>You are required to:</p>
<ul>
<li><em>Prepare a dilute solution of solution hydroxide, solution B </em><em>b). Determine the:</em>
<ul>
<li><em>Molar mass of the alkanoic acid</em></li>
<li><em>Reaction ratio between sodium hydroxide and acid A</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>Procedure I</h3>
<p>Using a pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution B into a 250.0ml volumetric flask. Add about 200cm<sup>3</sup> of distilled water. Shake well. Add more distilled water to make upto the mark. Label this solution D. Retain the remaining solution B for use in procedure II.</p>
<p> ;</p>
<p>Fill a burette with solution C. using a clean pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution D into a 250ml conical flask. Add two drops of phenolphthalein indicator and titrate with solution C. record your results in table</p>
<p> ;</p>
<ol>
<li><em>Repeat the titration two more times and complete the </em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="368"><em>Table</em></td>
<td width="90"><em>1</em><em>st</em></td>
<td width="98"><em>2</em><em>nd</em></td>
<td width="129"><em>3</em><em>rd</em></td>
</tr>
<tr>
<td width="368"><em>Final burette reading</em></td>
<td width="90"> ;</td>
<td width="98"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="368"><em>Final burette reading</em></td>
<td width="90"> ;</td>
<td width="98"> ;</td>
<td width="129"> ;</td>
</tr>
<tr>
<td width="368"><em>Volume of solution C used (cm<sup>3</sup>) added</em></td>
<td width="90"> ;</td>
<td width="98"> ;</td>
<td width="129"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<h3>Determine the:</h3>
<ul>
<li><em>Average volume of solution C used (1 mark)</em></li>
<li><em>Concentration of solution D in moles per litre </em><em>(1 mark) iii). Concentration of the alkanoic acid in solution C in moles per litre (1 mole</em></li>
</ul>
<p>of the acid reacts with 3 moles of the base) (1 mark)</p>
<p> ;</p>
<p>iv). Molar mass of the alkanoic acid (1 mark)</p>
<p> ;</p>
<h3>Procedure II</h3>
<p>Fill a clean burette with solution A. place 5cm3 of solution A into a 100ml beaker. Measure the initial temperature of solution A in the beaker record it in table II. Using a 10ml or a 100ml measuring cylinder, measures 25cm<sup>3</sup> of solution B. add it to solution A in the beaker and immediately stir the mixture with the thermometer. Record the maximum temperature reached in table II. Repeat the experiment with other sets of volumes of solutions A and B complete the table.</p>
<p> ;</p>
<h3>Table II</h3>
<table>
<tbody>
<tr>
<td width="330"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="68"><em>5</em></td>
<td width="75"><em>9</em></td>
<td width="68"><em>13</em></td>
<td width="68"><em>17</em></td>
<td width="68"><em>21</em></td>
<td width="62"><em>25</em></td>
</tr>
<tr>
<td width="330"><em>Volume of solution B (cm<sup>3</sup>)</em></td>
<td width="68"><em>25</em></td>
<td width="75"><em>21</em></td>
<td width="68"><em>17</em></td>
<td width="68"><em>13</em></td>
<td width="68"><em>9</em></td>
<td width="62"><em>5</em></td>
</tr>
<tr>
<td width="330"><em>Maximum temperature (<sup>0</sup>C)</em></td>
<td width="68"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="62"> ;</td>
</tr>
<tr>
<td width="330"><em>Initial</em> <em>temperature</em> <em>(<sup>0</sup>C)</em></td>
<td width="68"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="62"> ;</td>
</tr>
<tr>
<td width="330"><em>Change in temperature, âT</em></td>
<td width="68"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="62"> ;</td>
</tr>
</tbody>
</table>
<p>(6 marks)</p>
<ol>
<li><em>On the grid provided, plot a graph of âT (Vertical axis) against the volume </em><em>of solution A (3 marks)</em></li>
<li><em>F</em><em>r</em><em>o</em><em>m</em> <em>t</em><em>h</em><em>e</em> <em>g</em><em>r</em><em>a</em><em>ph</em><em>,</em> <em>d</em><em>e</em><em>t</em><em>e</em><em>r</em><em>m</em><em>i</em><em>n</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>A</em> <em>whic</em><em>h</em> <em>g</em><em>a</em><em>v</em><em>e</em> <em>t</em><em>h</em><em>e </em><em>maximum</em> <em>change</em> <em>in</em> <em>temperature </em><em>(1 mark)</em></li>
<li><em>Determine the volume of solution B that reacted with the volume of </em><em>solution A in (b) above (1 mark)</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<ol>
<li><em>Calculate</em> <em>the:</em>
<ul>
<li><em>Ratio between the volumes of solutions A and B that neutralized one </em><em>(1 mark)</em></li>
<li><em>Concentration in moles per litre of the acid in solution (assume that the volume ratio is the same as the mole ratio). </em><em>(1 mark)</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<h3>2. You are provide with solids E, F and G.</h3>
<p>Cary out the tests below and write your observations and inferences in the spaces provided</p>
<ul>
<li><em>Place all of solid E in a boiling Add 20cm<sup>3</sup> of distilled water and </em><em>shake until all the solid dissolves. Label this as solution E.</em>
<ul>
<li><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>E</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>4</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>2</em><em>M </em><em>sulphuric (VI) </em></li>
</ul>
</li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (2 marks)</p>
<ul>
<li><em>T</em><em>o</em> <em>a</em><em>bou</em><em>t</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>E</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>2</em><em>M</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m </em><em>hydroxide dropwise until in </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>Place one half of solid F in a test-tube. Add 2cm<sup>3</sup> of distilled water</em></li>
</ul>
<p> ;</p>
<p>and shake well. Add 4 drops of this solution to about 2cm<sup>3</sup> of solution E in a test-tube.</p>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To about 2cm<sup>3</sup> of solution E in a test tube, add 2 drops of aqueous potassium </em></li>
</ul>
<p>Observations Inferences</p>
<p>(1mark) (1 mark)</p>
<p> ;</p>
<ol>
<li><em>To about 2cm<sup>3</sup> of the solution obtained in (ii) above, add 3 drops acidified </em><em>potassium manganate (VII).</em></li>
</ol>
<p>Observations Inferences</p>
<p>(1 mark) (1 mark)</p>
<ul>
<li><em>To about 2cm<sup>3</sup> of the solution obtained in (ii) above, add 2 drops of </em><em>bromine </em></li>
</ul>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<ol>
<li><em>To the remaining solution G in the boiling tube, add the other half of solid </em></li>
</ol>
<p>Observations Inferences</p>
<p> ;</p>
<p>(1 mark) (1 mark)</p>
<h2>OCTOBER /NOVEMBER 2011</h2>
<p><strong> </strong></p>
<ol>
<li><em>You are provided with:</em>
<ul>
<li><em>60g of solid <strong>A </strong>, dibasic acid</em></li>
<li><em>Solution <strong>B </strong>containing 75g per litre of salt <strong>B</strong>.</em></li>
<li><em>Aqueous</em> <em>sodium</em> <em>hydroxide,</em> <em>solution </em></li>
<li><em>Phenolphthalein </em></li>
</ul>
</li>
</ol>
<p> ;</p>
<h3>You are required to prepare a solution of solid A and use it to determine the:-</h3>
<ul>
<li><em>Concentration of sodium</em> <em>hydroxide, solution <strong>C</strong></em></li>
</ul>
<ul>
<li><em>React salt <strong>B </strong>with excess sodium hydroxide and then determine the </em><em>relative molecular mass of salt <strong>B</strong>.</em></li>
</ul>
<p> ;</p>
<h3>Procedure I</h3>
<ul>
<li><em>Using a burette, place 0cm<sup>3</sup> of solution B in each of two 250ml conical flasks. Using a pipette and a pipette filler, add 25.0cm<sup>3</sup> of solution <strong>C </strong>to each of the two conical flasks. The sodium hydroxide added is in excess). Label the conical flasks 1 and 2.</em></li>
<li><em>Heat the contents of first of the first conical flask to boiling and then let the mixture boil for five Allow the mixture to cool.</em></li>
<li><em>Repeat procedure (b) with second conical flask. While the mixtures are cooling, proceed with procedure II.</em></li>
</ul>
<p> ;</p>
<h3>Procedure II</h3>
<ul>
<li><em>Place <strong>all </strong>solid <strong>A in </strong>a 250ml volumetric flask. Add about 150cm<sup>3</sup> of distilled water, shake well dissolve the solid and then add water to make up to the Label this as solution A.</em></li>
<li><em>Place solution A in a clean Using a pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution C in a 250ml conical flask. Add 2 drops of phenolphathein indicator and titrate with solution A. Record your results in Table 1. Repeat the titration two more times and complete the table.</em></li>
</ul>
<p> ;</p>
<h3>Table 1</h3>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="99"><em>III</em></td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution <strong>A </strong>used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>Calculate the:</h3>
<p><strong> </strong></p>
<ul>
<li><em>Average volume of solution A used: ( ½ mark)</em></li>
<li><em>Concentration in moles per litre of the dibasic acid in solution A; </em><em>(Relative molecular mass of A is 126) (2 marks)</em></li>
<li><em>M</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em><em> acid used; (1 mark)</em></li>
<li><em>Moles of sodium hydroxide in 0cm<sup>3</sup> of solution <strong>C</strong>. (1 mark)</em></li>
<li><em>Concentration of sodium hydroxide in moles per litre </em><em>(2 marks) <strong>Procedure III</strong></em></li>
</ul>
<p>Add 2 drops of phenolphthalein indicator to the contents of the first conical flask prepared in procedure I and titrate with solution A. Record your results in Table 2. Repeat the procedure with the contents of the second conical flask and complete the table.</p>
<p> ;</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="165"><em>1<sup>st</sup> Conical flask</em></td>
<td width="188"><em>2<sup>nd</sup> Conical Flask</em></td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="165"> ;</td>
<td width="188"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="165"> ;</td>
<td width="188"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution A used (cm<sup>3</sup>)</em></td>
<td width="165"> ;</td>
<td width="188"> ;</td>
</tr>
</tbody>
</table>
<p>(3 marks)</p>
<p>Calculate the: &#8211;</p>
<ul>
<li><em>a</em><em>v</em><em>e</em><em>r</em><em>a</em><em>g</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>A</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>;</em><em> ( ½mark)</em></li>
<li><em>M</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>;</em><em> (1 mark)</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Moles of sodium hydroxide that reacted with the basic </em><em>(1</em> <em>mark)</em></li>
<li><em>Moles of sodium hydroxide that reacted with 0cm<sup>3</sup></em> <em>of salt <strong>B</strong></em> <strong><em>i</em></strong><em>n solution <strong>B;</strong></em></li>
</ul>
<p>(2 marks)</p>
<ul>
<li><em>Given that 1 mole of salt B reacts with 2 moles of sodium hydroxide . Calculate </em><em>the : &#8211;</em>
<ol start="25">
<li><em>Number of moles of salt <strong>B </strong>in 0cm<sup>3</sup> of solution <strong>B; </strong>( 1 mark)</em></li>
<li><em>Concentration in moles per litre of salt <strong>B </strong>in solution <strong>B </strong>; </em><em>( 1 mark)</em></li>
</ol>
</li>
</ul>
<ul>
<li><em>Relative molecular mass of salt <strong>B</strong>; </em><em>( 2 marks)</em></li>
</ul>
<p> ;</p>
<ol start="2">
<li><em>(a) (i) You are provided with solid Carry out the following tests and write <strong>your </strong>observations and inferences in the spaces provided</em></li>
</ol>
<p> ;</p>
<p>Observations Inferences</p>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<p> ;</p>
<p>(ii) Place the rest of solid D in a boiling tube. Add about 10cm<sup>3</sup> of distilled water. Shake well.</p>
<p> ;</p>
<p>To a 2cm<sup>3</sup> portion of the solution, add about 1cm<sup>3</sup> of hydrogen peroxide and shake well. To the resulting mixture, add aqueous sodium hydroxide drop wise until in excess.</p>
<p> ;</p>
<h3>Observations Inferences</h3>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>You are provided with solution E. Carry out the following tests and write </em><em>your observations and inferences in the spaces </em></li>
</ul>
<p> ;</p>
<p>Divide solution <strong>E </strong>into <strong>two </strong>observations.</p>
<ul>
<li><em>To one portion of solution E in a test tube, add 3 drops of barium </em><em> <strong>Retain the mixture for use in test (ii) below.</strong></em></li>
</ul>
<p><strong> </strong></p>
<h3>Observations Inferences</h3>
<p>(1 mark) (2 marks)</p>
<p> ;</p>
<ul>
<li><em>To mixture obtained in (i) above, add about 5cm<sup>3</sup> of 2M nitric (V) </em><em>acid</em></li>
</ul>
<p> ;</p>
<h3>Observations Inferences</h3>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<h2>OCTOBER /NOVEMBER 2012</h2>
<p> ;</p>
<h3>1. You are provided with:</h3>
<ul>
<li><em>Solution</em> <strong><em>A</em></strong> <em>containing</em> <em>an</em> <em>oxidising agent <strong>A</strong>;</em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <strong><em>B</em></strong><em>,</em> <em>0</em><em>.</em><em>05</em><em>M</em> <em>a</em><em>q</em><em>u</em><em>e</em><em>o</em><em>u</em><em>s</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>t</em><em>h</em><em>i</em><em>o</em><em>s</em><em>u</em><em>l</em><em>pha</em><em>t</em><em>e</em><em>;</em></li>
<li><em>Solution</em> <strong><em>C </em></strong><em>, containing</em> <em>a reducing agent <strong>C</strong>;</em></li>
<li><em>Aqueous potassium iodide;</em></li>
<li><em>Solution <strong>D</strong>, starch </em></li>
</ul>
<p> ;</p>
<h3>You are required to determine the:</h3>
<ul>
<li><em>Concentration of solution A</em></li>
<li><em>Rate of reaction between the oxidising agent A and the reducing agent <strong>C</strong>.</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h3>Procedure 1</h3>
<p><strong> </strong></p>
<ol>
<li><em>Using a pipette and a pipette filler, place 25.0cm<sup>3</sup> of solution <strong>A </strong>into a 250ml </em><em>conical </em></li>
<li><em>Measure 10cm<sup>3</sup> of aqueous potassium iodide and add it to solution <strong>A in </strong>the conical Shake the mixture. Add 10cm<sup>3</sup> of 2M sulphuric (VI) acid to the mixture and shake.</em></li>
<li><em>Fill a burette with solution <strong>B </strong>and use it to titrate the mixture <strong>in the conical flask </strong></em><strong><em>until </em></strong><em>it just turns orange – Add 2cm<sup>3</sup> of solution <strong>D </strong>to the mixture in a conical flask. Shake thoroughly. Continue titrating until the mixture just turns colourless. Record your results in <strong>table 1 </strong>below.</em></li>
<li><em>Repeat the procedure and complete table <strong>Retain the remainder </strong>of solution A and solution <strong>D </strong>for use in procedure II.</em></li>
</ol>
<p> ;</p>
<h3>Table 1</h3>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="99"><em>III</em></td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
<tr>
<td width="345"><em>Volume of solution <strong>B </strong>used (cm<sup>3</sup>)</em></td>
<td width="120"> ;</td>
<td width="105"> ;</td>
<td width="99"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<p> ;</p>
<ul>
<li><em>Calculate</em> <em>the:</em>
<ul>
<li><em>A</em><em>v</em><em>e</em><em>r</em><em>a</em><em>g</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>B</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>;</em><em> ( 1mark)</em></li>
<li><em>Number of moles of sodium thiosulphate . ( 1mark)</em></li>
</ul>
</li>
<li><em>Gi</em><em>v</em><em>e</em><em>n</em> <em>t</em><em>h</em><em>a</em><em>t</em> <em>o</em><em>n</em><em>e</em> <em>m</em><em>o</em><em>l</em><em>e</em> <em>o</em><em>f</em> <em>A</em> <em>r</em><em>e</em><em>a</em><em>c</em><em>t</em><em>s</em> <em>wi</em><em>t</em><em>h</em> <em>s</em><em>i</em><em>x</em> <em>m</em><em>o</em><em>l</em><em>e</em><em>s</em><em> of sodium thiosulphate, calculate the;</em>
<ul>
<li><em>N</em><em>u</em><em>m</em><em>be</em><em>r</em> <em>o</em><em>f</em> <em>m</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>A</em> <em>t</em><em>h</em><em>a</em><em>t</em> <em>we</em><em>r</em><em>e</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>;</em><em> ( 1mark)</em></li>
<li><em>Concentration of solution A in moles per </em><em>( 2marks)</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<h3>Procedure II</h3>
<p> ;</p>
<ol>
<li><em>Label six test tubes as 1, 2, 3, 4, 5 and 6 and a place them in test- tube </em></li>
<li><em>using a clean burette, measure the volumes of distilled water shown n table 2 </em><em>into the labelled test tubes</em></li>
<li><em>Using</em> <em>a</em> <em>burette,</em> <em>measure</em> <em>the</em> <em>volumes</em> <em>of</em> <em>solution</em> <em>A</em> <em>shown</em> <em>in</em> <em>table</em> <em>2</em> <em>into</em> <em>each</em> <em>of</em> <em>the test tubes</em></li>
<li><em>Clean the burette and rinse it with about 5cm<sup>3</sup> of solution </em></li>
<li><em>Using the burette, measure 5cm<sup>3</sup> of solution C and place it into a 100ml </em></li>
<li><em>Using a 10ml measuring cylinder, measure 5 cm<sup>3</sup> of solution D and add it to the beaker containing solution Shake the mixture</em></li>
<li><em>Pour the contents of test – tube number 1 to the mixture </em><em>in the beaker and immediately start a stop watch. Swirl the contents of the beaker. Record the time taken for a blue colour to appear in table </em></li>
</ol>
<p> ;</p>
<ol start="8">
<li><em>Repeat steps 5 to 7 using the contents of test- tube numbers 2,3,4,5 and </em></li>
<li><em>Complete table 2 by computing Rate = 1/Time (S<sup>-1</sup>)</em></li>
</ol>
<p> ;</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="302"><em>Test-tube number</em></td>
<td width="75"><em>1</em></td>
<td width="75"><em>2</em></td>
<td width="83"><em>3</em></td>
<td width="75"><em>4</em></td>
<td width="68"><em>5</em></td>
<td width="62"><em>6</em></td>
</tr>
<tr>
<td width="302"><em>Volume of distilled water (cm<sup>3</sup>)</em></td>
<td width="75"><em>0</em></td>
<td width="75"><em>2</em></td>
<td width="83"><em>3</em></td>
<td width="75"><em>5</em></td>
<td width="68"><em>6</em></td>
<td width="62"><em>7</em></td>
</tr>
<tr>
<td width="302"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="75"><em>10</em></td>
<td width="75"><em>8</em></td>
<td width="83"><em>7</em></td>
<td width="75"><em>5</em></td>
<td width="68"><em>4</em></td>
<td width="62"><em>3</em></td>
</tr>
<tr>
<td width="302"><em>Time (seconds)</em></td>
<td width="75"> ;</td>
<td width="75"> ;</td>
<td width="83"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="62"> ;</td>
</tr>
<tr>
<td width="302"><em>Rate = 1/Time (S<sup>-1</sup>)</em></td>
<td width="75"> ;</td>
<td width="75"> ;</td>
<td width="83"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="62"> ;</td>
</tr>
</tbody>
</table>
<p>a). Plot a graph of rate (y-axis) against volume of solution A. (3 marks) b). What time would be taken for the blue colour to appear if the experiment</p>
<p>was repeated using 4 cm<sup>3</sup> of distilled water and 6 cm<sup>3</sup> of solution A?</p>
<p>(2</p>
<p>marks)</p>
<p> ;</p>
<ol start="2">
<li><em>You are provided with solid carry out the experiments below. Write your </em><em>observations and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<p>Place all of solid E in a boiling tube. Add 20 cm<sup>3</sup> of distilled water and shake until all the solid dissolves, label the solution as solution E. Use solution E for experiments (i) and (ii).</p>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>E</em><em>,</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>b</em><em>e</em> <em>i</em><em>n</em> <em>e</em><em>a</em><em>c</em><em>h</em> <em>o</em><em>f</em> <em>e</em><em>x</em><em>pe</em><em>r</em><em>i</em><em>m</em><em>e</em><em>n</em><em>t</em><em>s</em> <em>I</em><em>,</em> <em>II</em><em>,</em> <em>II</em><em>I</em> <em>a</em><em>n</em><em>d</em> <em>I</em><em>V</em><em>, </em><em>add;</em>
<ol>
<li><em>T</em><em>w</em><em>o</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>a</em><em>q</em><em>u</em><em>e</em><em>o</em><em>u</em><em>s</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>s</em><em>u</em><em>l</em><em>pha</em><em>t</em><em>e</em><em>; </em><strong><em>Observations Inferences</em></strong></li>
</ol>
</li>
</ul>
<p><strong> </strong></p>
<p>(1 mark) (1 mark)</p>
<ol>
<li><em>Five drops of aqueous sodium chloride;</em></li>
</ol>
<h3>Observations Inferences</h3>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="46"><strong><em> </em></strong></p>
<p><em>III.</em></td>
<td width="326"><em>(1 mark)</em></p>
<p><em>Two drops of barium nitrate; </em><strong><em>Observations</em></strong></td>
<td width="212"><em>(1 mark)</em></p>
<p><strong><em> </em></strong></p>
<p><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="46"><strong><em> </em></strong></p>
<p><em>IV.</em></td>
<td width="326"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></p>
<p><em>Two drops of lead (II) nitrate; </em><strong><em>Observations</em></strong></td>
<td width="212"><strong><em> </em></strong></p>
<p><em>(1 mark)</em></p>
<p><strong><em> </em></strong></p>
<p><strong><em>Inferences</em></strong></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em><em> 2cm<sup>3</sup> of solution E, in a test-tube, add 5 drops of aqueous sodium Add the piece of aluminium foil provided to the mixture and shake. Warm the mixture and test any gas produced with both blue and red litmus papers. (1 mark)</em></li>
</ul>
<p> ;</p>
<h3>Observations Inferences</h3>
<p>(2 marks) (1 mark)</p>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid Carry out the following tests. Write your </em><em>observations and inferences in the spaces provided.</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Place all of solid F in a boiling Add about 20 cm<sup>3</sup> of distilled water and shake until all the solid dissolves. Label the solution as solution F. Add about half of the solid sodium hydrogen carbonate provided to 2cm<sup>3</sup> of solution F.</em></li>
</ul>
<h3>Observations Inferences</h3>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>i). Add about 10cm<sup>3</sup> of dilute hydrochloric acid to the rest of solution F in the boiling Filter the mixture. Wash the residue with about 2cm<sup>3</sup> of distilled water. Dry the residue between filter papers. Place about one third of the dry residue on a metallic spatula and burn it in a Bunsen burner flame</em></li>
</ul>
<h3>Observations Inferences</h3>
<p><strong> </strong></p>
<p>(1 mark) (1 mark)</p>
<p>ii). Place all the remaining residue into a boiling tube. Add about 10cm<sup>3</sup> of distilled water and shake thoroughly. Retain the mixture for the tests in (C).</p>
<h3>Observations Inferences</h3>
<p><strong> </strong></p>
<p>(½ mark) (½ mark)</p>
<ul>
<li><em>Divide the mixture into two portions:</em>
<ul>
<li><em>T</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>r</em><em>s</em><em>t</em> <em>po</em><em>r</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>t</em><em>h</em><em>e</em> <em>r</em><em>e</em><em>s</em><em>t</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em><em>,</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>g</em><em>e</em><em>n</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p>carbonate</p>
<h3>Observations Inferences</h3>
<p><strong> </strong></p>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<ul>
<li><em>To the second portion, add two drops of bromine water </em><strong><em>Observations Inferences</em></strong></li>
</ul>
<p>(1 mark) (1 mark)</p>
<p> ;</p>
<p><strong><em><u>OCTOBER / NOVEMBER 2013</u></em></strong></p>
<p><strong> </strong></p>
<h3>You are provided with:</h3>
<ul>
<li><em>Solution A, aqueous copper (II) sulphate:</em></li>
<li><em>S</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>B</em><em>,</em> <em>i</em><em>r</em><em>o</em><em>n</em> <em>powde</em><em>r</em><em>:</em></li>
<li><em>0</em><em>.</em><em>0</em><em>2</em> <em>m</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>i</em><em>f</em><em>i</em><em>e</em><em>d</em> <em>po</em><em>t</em><em>a</em><em>ss</em><em>i</em><em>u</em><em>m</em> <em>m</em><em>a</em><em>n</em><em>g</em><em>a</em><em>n</em><em>a</em><em>t</em><em>e</em> <em>(</em><em>V</em><em>II</em><em>)</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em><em>.</em></li>
<li><em>You are required to determine the molar heat of displacement of copper by </em></li>
</ul>
<p> ;</p>
<h3>Procedure I.</h3>
<p>Using a burette, place 50.0cm<sup>3</sup> of solution A in a 100ml beaker. Measure</p>
<p> ;</p>
<h3>PROCEDURE I.</h3>
<p>Using a burette, place 50.0cm<sup>3</sup> of solution A in a 100 ml beaker. Measure the temperature of the solution and record it in table I below. Add all of solid B provided at once and start a stop watch. Stir the mixture thoroughly with the thermometer and record the temperature of the mixture after every one minute in the table. Retain the mixture for use in procedure II below.</p>
<p> ;</p>
<h3>Table I.</h3>
<table>
<tbody>
<tr>
<td width="240"><em>Time (Min.)</em></td>
<td width="83"><em>0</em></td>
<td width="75"><em>1</em></td>
<td width="68"><em>2</em></td>
<td width="68"><em>3</em></td>
<td width="60"><em>4</em></td>
<td width="60"><em>5</em></td>
<td width="60"><em>6</em></td>
<td width="53"><em>7</em></td>
</tr>
<tr>
<td width="240"><em>Temperature (<sup>0</sup>C)</em></td>
<td width="83"> ;</td>
<td width="75"> ;</td>
<td width="68"> ;</td>
<td width="68"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="60"> ;</td>
<td width="53"> ;</td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ol>
<li>a) i). Plot a graph of temperature (vertical axis) against time in the grid</li>
</ol>
<ul>
<li><em>F</em><em>r</em><em>o</em><em>m</em> <em>t</em><em>h</em><em>e</em> <em>g</em><em>r</em><em>a</em><em>ph</em><em>,</em> <em>d</em><em>e</em><em>t</em><em>e</em><em>r</em><em>m</em><em>i</em><em>n</em><em>e</em> <em>t</em><em>he</em><em>:</em>
<ol>
<li><em>H</em><em>i</em><em>g</em><em>he</em><em>s</em><em>t</em> <em>c</em><em>h</em><em>a</em><em>n</em><em>g</em><em>e</em> <em>i</em><em>n</em> <em>t</em><em>e</em><em>m</em><em>pe</em><em>r</em><em>a</em><em>t</em><em>u</em><em>r</em><em>e</em><em>,</em> <em>△</em><em>T</em><em>:</em><em> (1 mark)</em></li>
<li><em>Time taken for reaction to be completed </em><em>( ½ mark)</em></li>
</ol>
</li>
</ul>
<ul>
<li><em>Calculate the heat change for the (Specific heat </em><em>capacity of</em></li>
</ul>
<p>solution is 4.2Jg-1 K-1; Density of the solution is 1 gcm<sup>3</sup>).</p>
<p>(2</p>
<p>marks)</p>
<p> ;</p>
<h3>PROCEDURE II</h3>
<p>Carefully decant the mixture obtained in procedure I into a 250ml volumetric flask. Add</p>
<p> ;</p>
<p>about 10cm<sup>3</sup> of distilled water to the residue in the 100 ml beaker. Shake well, allow the mixture to settle and carefully decant into the volumetric flask. Immediately, add about 50cm<sup>3</sup> of 2M sulphuric (VI) acid to the mixture in the volumetric flask. Add more distilled water to make 250.0 cm<sup>3</sup> of solution. Label this as solution D.</p>
<p>Fill a burette with solution C. Using a pipette and pipette filler, place 25.0cm<sup>3</sup> of solution D into a 250 ml conical flask. Titrate solution D against solution C until the first permanent pink colour is obtained. Record your results in table 2 below. Repeat the titration two more times and complete the table. Retain the remaining solution C for use in question 3.</p>
<h3>Table 2</h3>
<table>
<tbody>
<tr>
<td width="398"> ;</td>
<td width="143"><em>I</em></td>
<td width="128"><em>II</em></td>
<td width="122"><em>III</em></td>
</tr>
<tr>
<td width="398"><em>Final burette reading</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
<tr>
<td width="398"><em>Initial burette reading</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
<tr>
<td width="398"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
</tbody>
</table>
<p>(4 marks)</p>
<ul>
<li><em>Determine</em> <em>the</em> <em>average</em> <em>volume</em> <em>of</em> <em>solution</em> <em>C used (1 mark)</em>
<ul>
<li><em>Transfer about half of the dry residue into a dry test-tube. Heat the residue </em><em>strongly and test any gas produced using a burning splint</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Place the rest of the residue in a dry test-tube. Add 4cm<sup>3</sup> of 2M hydrochloric Retain the mixture for test (iii) below.</em></li>
</ul>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li></li>
</ul>
<table>
<tbody>
<tr>
<td width="541">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<ul>
<li><em>To 2cm<sup>3</sup> of the solution obtained in (ii) above, add 6cm<sup>3</sup> of aqueous ammonia </em></li>
</ul>
<p> ;</p>
<ul>
<li><em>i). To 2cm<sup>3</sup> of the filtrate</em></li>
</ul>
<p>obtained in (a) above, add about 3cm3 of aqueous ammonia (Excess).</p>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>To 2cm<sup>3</sup> of the filtrate, add about 2cm<sup>3</sup> of 2M hydrochloric </em></li>
</ul>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>To 2cm<sup>3</sup> of the filtrate, add one or two drops of barium nitrate </em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol start="3">
<li><em>You are provided with solid G. Carry out the tests in (a) and (b) and write your observations and inferences in the spaces Describe the method used in part (c).</em>
<ul>
<li><em>Place about one third of solid G on a metallic spatula and burn it in a Bunsen burner flame</em></li>
</ul>
</li>
</ol>
<table>
<tbody>
<tr>
<td width="270"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="270"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Dissolve all of the remaining solid G in about 10cm<sup>3</sup> of distilled water in a boiling Use the solution for tests (b) (i), (ii) and (c).</em>
<ul>
<li><em>Place 2 cm<sup>3</sup> of the solution in a test-tube and add 2 drops of acidified potassium manganate (VII); solution </em></li>
</ul>
</li>
</ul>
<table>
<tbody>
<tr>
<td width="285"><em>Observations</em></td>
<td width="324"><em>Inferences</em></td>
</tr>
<tr>
<td width="285"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="324"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>T</em><em>o</em> <em>2</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>a</em><em>l</em><em>l</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>g</em><em>e</em><em>n</em> <em>c</em><em>a</em><em>r</em><em>bona</em><em>t</em><em>e </em></li>
</ul>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="317"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="317"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ul>
<li><em>Determine the p H of the solution obtained in (b) above</em></li>
</ul>
<table>
<tbody>
<tr>
<td width="210"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="210"><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="399"><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>CO-ORDINATED MARK SCHEMES</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>NOVEMBER 1995 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><em>1.</em></p>
<table>
<tbody>
<tr>
<td width="193"><em>Time (min)</em></td>
<td width="51"><em>0</em></td>
<td width="51"><em>½</em></td>
<td width="51"><em>1</em></td>
<td width="51"><em>1 ½</em></td>
<td width="51"><em>2</em></td>
<td width="33"><em>2</em></p>
<p><em>½</em></td>
<td width="51"><em>3</em></td>
<td width="51"><em>3 ½</em></td>
<td width="51"><em>4</em></td>
<td width="51"><em>4 ½</em></td>
<td width="51"><em>5</em></td>
</tr>
<tr>
<td width="193"><em>Temperature (0<sup>C</sup>)</em></td>
<td width="51"><em>23.5</em></td>
<td width="51"><em>23.5</em></td>
<td width="51"><em>23.5</em></td>
<td width="51"><em>23.5</em></td>
<td width="51"><em>23.5</em></td>
<td width="33"> ;</td>
<td width="51"><em>15.5</em></td>
<td width="51"><em>16.0</em></td>
<td width="51"><em>16.5</em></td>
<td width="51"><em>17.0</em></td>
<td width="51"><em>17.5</em></td>
</tr>
</tbody>
</table>
<p><strong><em>Table I </em></strong><em>(3 Marks)</em></p>
<ul>
<li><em>C</em><em>o</em><em>m</em><em>ple</em><em>t</em><em>e</em> <em>wi</em><em>t</em><em>h</em> <em>1</em><em>0</em> <em>r</em><em>e</em><em>a</em><em>d</em><em>i</em><em>n</em><em>g</em><em>s</em><em>;</em> <em>i</em><em>f</em> <em>1</em><em><sup>s</sup></em><em><sup>t</sup></em> <em>r</em><em>e</em><em>a</em><em>d</em><em>i</em><em>n</em><em>g</em> <em><u>>;</u></em> <em>4</em><em>0</em> <em>o</em><em>r</em> <em><u><;</u></em><em>1</em><em>0</em> <em>t</em><em>he</em><em>n</em> <em>u</em><em>n</em><em>r</em><em>e</em><em>a</em><em>l</em><em>i</em><em>s</em><em>t</em><em>i</em><em>c</em> <em>(</em><em>a</em><em>wa</em><em>r</em><em>d</em> <em>0</em><em>)</em></li>
<li><em>Decimal</em> <em>(D)</em> <em>–</em> <em>½</em> <em>&#8211;</em> <em>Accept</em> <em>whole</em> <em>numbers</em> <em>and</em> <em>or</em> <em>decimals</em> <em>to</em> <em>d.c.p</em> <em>only</em> <em>c</em> <em>1<sup>st</sup></em> <em>d.c.p value as 0 or 5 only</em></li>
<li><em>Accuracy</em> <em>– </em><em>½ &#8211; 1<sup>st</sup> reading should be within +2<sup>0</sup> of school value</em></li>
<li><em>Trends – 1 – (1/2, ½) as </em><em>i).Readings</em> <em>betweens 0 -2 minutes should be constant (½)</em></li>
</ul>
<p><em>ii).Readings</em> <em>between</em> <em>3</em> <em>-5</em> <em>min</em> <em>should</em> <em>use</em> <em>continuously</em> <em>(½)</em></p>
<p> ;</p>
<p><strong><em>NB; </em></strong><em>Reaction is endothermic hence temperature must drop in minute 3. If not penalize ½ mark</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Temp</em></strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="74"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p> ;</p>
<p><strong> </strong></p>
<p><em>Fall in temperature âT1=</em><em>&#8230;&#8230;&#8230;&#8230;&#8230;. </em><em>15</em> <em>–</em> <em>0</em> <em>–</em> <em>23.5 = &#8211; 8.5<sup>0</sup>C</em></p>
<p><em>(1 mark)</em></p>
<p> ;</p>
<p><em>Graph I </em><em>(3 Marks)</em></p>
<p><em>Scale (sc) – ½ &#8211; plots should cover (4 ½ x 3 ½ squares) or more</em></p>
<p><em>Plots</em> <em>(Pt)</em> <em>–</em> <em>1</em> <em>–</em> <em>if</em> <em>3</em> <em>readings</em> <em>incorrect</em> <em>give</em> <em>½</em> <em>but</em> <em>if</em> <em>more</em> <em>than 3 incorrect (award 0) If correct scale intervals correct only.</em></p>
<p><em>Lines (Lns) – 1 – ½ (for each line) lines should pass through at least three points for each line Xtrapolation (ext) – ½ &#8211; for the second line extended downwards</em></p>
<p><em>â T</em><em>1 </em><em>= 1 </em><em>– </em><em>a). show âT</em><em>1 </em><em>on graph at 2 ½ minute ( ½ mark) </em><em>b). Ignore sign of âT value</em></p>
<p> ;</p>
<p><em>a). i). n</em><em>1 </em><em>= <sup>2</sup>/</em><em>100 </em><em>= 0.02</em></p>
<p><em>Penalize ½ mark for wrong units i.e. m or M. Accept figure continuous units.</em></p>
<p><em>If wrong RFM used but shown how found, penalize ½ and mark answer if correct (using wrong RFM)</em></p>
<p><em>ii). <u>Mass of solution x 4.2 x âT</u></em><em><u>1</u></em></p>
<p> ;</p>
<p><em>âH</em><em>1 </em><em>n</em><em>1</em> <em>x</em><em> </em><em>1000</em></p>
<p><em>-1</em></p>
<p><em>Kjmol</em></p>
<p> ;</p>
<p> ;</p>
<p><em>Same as for graph I For correct substitution of</em></p>
<p><em>âT</em><em>1 </em><em>and n</em><em>1</em></p>
<p> ;</p>
<p> ;</p>
<p><em>Size 3 ½ x 3 ½ sq</em></p>
<p> ;</p>
<p><em>Correct answer should</em></p>
<p><em>Correct</em> <em>answer</em></p>
<p> ;</p>
<p><em>Be within +2 units correct in the 1<sup>st</sup> D.C.P (otherwise penalise ½) </em><em>Have correct sign (+ve) (otherwise per ½ mark)</em></p>
<p><em>Penalized ½ if wrong units used – accept lack of units (on second line only)</em></p>
<ol>
<li><em>b) i). n</em><em>2</em> <em>=</em><em><sup>1</sup></em><em>/</em><em>84</em><em>v </em><em>= 0119</em></li>
</ol>
<p><em>= 0. 012</em></p>
<p><em>Accept answer to 3 or 4 D.C.P only (Not 2 d.c.p)</em></p>
<p><em>If RFM is wrong (but shown it was calculated) Penalize ½ mark and mark answer if</em></p>
<p><em>correct using</em></p>
<p><em>the wrong RFM</em></p>
<p><em>ii).</em><em> </em><em>For</em><em> </em><em>correct</em><em> </em><em>subt</em><em> </em><em>of</em><em> </em><em>n</em><em>2</em> <em>+</em><em> </em><em>âT</em><em>2 = </em><em>Correct answer</em></p>
<p><em>Answer should be correct to within 12 units in 1<sup>st</sup> D.C.P</em></p>
<p><em>Answer should bear correct sign (-ve) otherwise penalize ½ mark</em><em> Accept units missing otherwise penalize ½ mark for wrong units used.</em></p>
<p> ;</p>
<ul>
<li><em>1</em><em>M</em><em>a</em><em>r</em><em>k &#8211; for correct substitution of âH</em><em>1</em><em>,</em><em> </em><em>â</em><em>H</em><em>2</em> <em>a</em><em>n</em><em>d</em><em> </em><em>â</em><em>H</em><em>3</em> <em>i</em><em>n</em><em>c</em><em>l</em><em>u</em><em>d</em><em>i</em><em>n</em><em>g</em><em> </em><em>t</em><em>he</em><em>i</em><em>r</em><em> </em><em>r</em><em>e</em><em>s</em><em>pec</em><em>t</em><em>i</em><em>v</em><em>e</em><em> </em><em>s</em><em>i</em><em>g</em><em>n</em><em>s</em></li>
</ul>
<p><em>e.g</em><em> </em><em>âH</em><em>4</em> <em>=</em><em> </em><em>2</em><em> </em><em>(26.8)</em><em> </em><em>–</em><em> </em><em>(-</em><em> </em><em>43.8)</em><em> </em><em>– </em><em>2(121)</em></p>
<p><em>= &#8211; 144.6 kj/mol</em></p>
<p><em>1 mark – for correct answer Penalize ½ mark for wrong sign on answer</em></p>
<p><em>Award 0 marks for wrong substitution or wrong sign transferred with âH in the substitution. </em><em>Penalise ½ mark for wrong units used</em></p>
<p><em>Penalize</em> <em>½</em> <em>mark</em> <em>for</em> <em>wrong</em> <em>transfer</em> <em>of</em> <em>any</em> <em>of the âH values</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>9 marks</em></strong></p>
<table>
<tbody>
<tr>
<td width="69"><em>2 (a)</em></td>
<td colspan="2" width="729"><em>Silvery / shiny grey/ metallic luster silvery white / shining metal</em></p>
<p><em>R</em><em>e</em><em>j</em><em>e</em><em>c</em><em>t</em> <em>s</em><em>h</em><em>i</em><em>n</em><em>y</em><em>,</em> <em>w</em><em>r</em><em>o</em><em>n</em><em>g</em> <em>c</em><em>o</em><em>l</em><em>o</em><em>u</em><em>r</em> <em>e</em><em>t</em><em>c</em><em>,</em> <em>s</em><em>i</em><em>l</em><em>ve</em><em>r</em><em>y</em> <em>whi</em><em>t</em><em>e</em> <em>e</em><em>t</em><em>c</em></td>
</tr>
<tr>
<td width="69"> ;</td>
<td width="330"><em>Observations</em></td>
<td width="399"><em>Inferences</em></td>
</tr>
<tr>
<td width="69"><em>(b)</em></td>
<td width="330"><em>turns black/grey/white</em></td>
<td width="399"><em>L reacts with oxygen in air to form oxide or L is</em></p>
<p><em>oxidize</em></td>
</tr>
<tr>
<td width="69"><em>(c)</em></td>
<td width="330"><em>Effervescence/bubbles/</em></p>
<p><em>gas produced / burns with a pop sound</em></td>
<td width="399"><em>metal L is above hydrogen in the reactivity series/ or mention any metal above H in reactivity series</em></p>
<p><em>OR just metal up in the series</em></td>
</tr>
<tr>
<td width="69"><em>(d)</em></td>
<td width="330"><em>Effervescence/bubbles/ gas produced/ gas burns with a pop sound.</em></td>
<td width="399"><em>metal L is above hydrogen in the reactivity series/ or mention any metal above H in reactivity series</em></p>
<p><em>OR just metal up in the series</em></td>
</tr>
<tr>
<td width="69"><em>(e)</em></td>
<td width="330"><em>Black/grey/dark coating OR deposit or ppt</em></p>
<p><em>or substance</em></td>
<td width="399"><em>Metal L is above Lead in reactivity series OR Lead</em></p>
<p><em>is displaced by L</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong><em>9 marks</em></strong></p>
<table>
<tbody>
<tr>
<td width="69"><em>3 (a)</em></td>
<td colspan="2" width="729"><em>White Crystalline solid/white powder /white solid</em></td>
</tr>
<tr>
<td width="69"><em>(b)</em></td>
<td colspan="2" width="729"><em>Burns with Lilac /purple/ violet flame / Reject blue flame</em></td>
</tr>
<tr>
<td width="69"><em>(c)</em></td>
<td width="330"><em>Gas relights burning splint</em><em> Solid melts forming colourless liquid</em></p>
<p><em>If</em> <em>melts</em> <em>to</em> <em>colourless</em> <em>solution</em></p>
<p><em>(Reject if just melts)</em></td>
<td width="399"><em>Oxygen/O</em><em>2 </em><em>evolved possibly KNO</em><em>3</em></p>
<p><em>Accept NaNO</em><em>3 </em><em>if not scored in (b)</em></td>
</tr>
<tr>
<td width="69"><em>(d)(i)</em></td>
<td width="330"><em>No visible change no effect on litmus</em></p>
<p><em>paper</em></td>
<td width="399"><em>Neutral solution</em></td>
</tr>
<tr>
<td width="69"><em>(ii)</em></td>
<td width="330"><em>No Precipitate / reject no observable change</em></td>
<td width="399"><em>Z</em><em>n</em><em>2</em><em>+</em><em>,</em><em> </em><em>A</em><em>l</em><em>3</em><em>+</em><em>,</em> <em>P</em><em>b</em><em>2</em><em>+</em><em>,</em></p>
<p><em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>M</em><em>g</em><em><sup>2</sup></em><em><sup>+</sup></em> <em>(</em><em>A</em><em>n</em><em>y</em> <em>3</em> <em>a</em><em>b</em><em>s</em><em>e</em><em>n</em><em>t</em><em>) </em><em>Or K<sup>+</sup> , Na<sup>+</sup> Present</em></td>
</tr>
<tr>
<td width="69"><em>(iii)</em></td>
<td width="330"><em>No precipitate.</em></td>
<td width="399"><em>CO <sup>2-</sup>, SO <sup>2-</sup> OR Cl<sup>&#8211;</sup> absent</em></p>
<p><em>3 4</em></p>
<p><em>(Any two mentioned)</em></td>
</tr>
<tr>
<td width="69"><em>(iv)</em></td>
<td width="330"><em>&#8211; Colourless fumes/gas/effervescence which turns moist red litmus blue</em></p>
<p><em>&#8211;</em> <em>Grey</em> <em>/</em> <em>black</em> <em>mixture/solid</em> <em>precipitate</em></td>
<td width="399">&#8211; <em>NH</em><em>3 </em><em>evolved</em></p>
<p>&#8211; <em>Solid</em> <em>contains Nitrogen or NO <sup>&#8211;</sup> ions</em></p>
<p><em>3</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong><em>NOVEMBER 1996 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Principles of averaging</em></strong></p>
<p><em>Values averaged must be shown and must be within + 0.20cm<sup>3</sup> of each other</em></p>
<p> ;</p>
<ol>
<li><em> c). Concentration of solution B = <u>23.5</u> Mol<sup>-1</sup> 392</em></li>
</ol>
<p><em>= 0.05995 Mol<sup>-1</sup></em></p>
<p><em>Note:</em> <em>(i)</em> <em>Accept answer given as 0.060 mol<sup>-1</sup> but reject 0.06 mol<sup>-1</sup></em></p>
<ul>
<li><em>Units need not be shown but if wrong units are given penalize ½ mk</em></li>
<li><em>Penalise</em> <em>½</em> <em>mark for wrong arithmetic</em></li>
</ul>
<ul>
<li><em>No of moles of iron (II) ions in 25cm<sup>3</sup> of solution B = <u>25</u> x in (c)</em></li>
</ul>
<p> ;</p>
<p><em>1000</em></p>
<p><em>= correct answer</em></p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Accept</em> <em>rounding</em> <em>off</em> <em>of answer to 4 p</em></li>
<li><em>penalize ½ mark if answer is rounded off to the 3<sup>rd</sup>p </em><em>iii</em><em>)</em><em>.</em><em> If wrong units are given, penalize ½ mark</em></li>
</ul>
<p> ;</p>
<p><strong><em>Use of 1<sup>st</sup> Principle Use of Formula Method</em></strong></p>
<ul>
<li></li>
</ul>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<ul>
<li><em>5 moles of Fe<sup>2+</sup> = 1mole of MnO <sup>&#8211;</sup> <u>M</u></em><em><u>1</u></em><em><u>V</u></em><em><u>1</u></em><em> </em><em>= <u>5</u></em></li>
</ul>
<p><em>No of moles of A (in litres) used M</em><em>2</em><em>V</em><em>2</em><em> </em><em>1</em></p>
<p><em>= <sup>1</sup>/</em><em>5 </em><em>x ans in (d)</em></p>
<p><em>No of moles of A in 1000cm<sup>3</sup> <u>ans (a) x pipette</u> = <u>5</u></em></p>
<p><em>= <sup>1</sup>/</em><em>5 </em><em>x ans in (d) x <sup>1000</sup>/</em><em>titre </em><em>M</em><em>2 </em><em>x titre</em><em> </em><em>1</em></p>
<p><em>Correct</em><em> </em><em>answer M</em><em>2 </em><em>= <u>Ans in © x Pipette</u></em></p>
<p><em>5 x titre</em></p>
<p><em>Correct</em> <em>answer</em></p>
<p><strong><em>Conditions Note</em></strong></p>
<ul>
<li><em>If step 1 not sown but correct a). If steps (i) and (ii) are not mole ratio used in step 2, credit shown but step (iii) and</em></li>
</ul>
<p><em>1 mark ans are correct</em></p>
<ul>
<li><em>Penalise ½ mark max 1 ½ marks</em></li>
</ul>
<p><em>for wrong arithmetic </em><em>b). if step (ii) and (iii)are iii). Penalize ½ mark for wrong combined to make M</em><em>2</em></p>
<p><em>units</em> <em>given the subject award 1 mark</em></p>
<p><em>iv). Accept rounding of to the for the combined step 3<sup>rd</sup> and 4<sup>th</sup> d.p</em></p>
<p><strong><em>Procedure II</em></strong></p>
<ul>
<li><em>No of moles of manganate (VII) ions in V</em><em>2 </em><em>= <u>Ans in (e) x Titre</u></em></li>
</ul>
<p><em>1000</em></p>
<p><em>= correct answer</em></p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Accept rounding off of answer to the 4<sup>th</sup> p</em></li>
<li><em>Penalise ½ mark if the mark is rounded off to the 3<sup>rd</sup>p </em><em>iii</em><em>)</em><em>.</em><em> If wrong units are given, penalize ½ mark</em></li>
</ul>
<p> ;</p>
<ul>
<li></li>
</ul>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<ul>
<li><em>2 moles of MnO <sup>&#8211;</sup> ions = 5 moles of dibasic acid</em></li>
</ul>
<p><em>No of moles of the dibasic acid in 25cm<sup>3</sup> of sol C = <sup>5</sup>/</em><em>2 </em><em>x ans in (h)</em></p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Penalise ½ mark for wrong units used</em></li>
<li><em>Penalise ½ mark for wrong arithmetic if not within 2 units in the 4<sup>th</sup> decimal place</em></li>
<li><em>Concentration</em> <em>of</em> <em>the dibasic acid in mol l-1 = <u>Ans in (i) x 1000</u></em></li>
</ul>
<p><em>Pipette</em></p>
<p><strong><em>Conditions</em></strong></p>
<p><em>i). Penalise ½ mark for wrong arithmetic if not within +2 units in the decimal place ii). Answer should be written to at least 3 decimal places, unless it divides exactly.</em></p>
<p><em>Otherwise penalize </em><em>½ mark</em></p>
<p><em>iii). Penalise ½ mark for wrong units used</em></p>
<p> ;</p>
<ul>
<li><em>RFM of the dibasic acid = 0</em></li>
</ul>
<p><em>ans in (j) ½ mark</em></p>
<p><em>= correct answer ½ mark X + 2 + 36 = RFM of dibasic acid ½ mark X + 38 = RFM of dibasic acid ½ mark Formula mass of X = RFM of dibasic acid – 38 ½ mark</em></p>
<p><em>Correct</em> <em>answer</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"> ;</td>
<td width="360"><em>Observations</em></td>
<td width="339"><em>Inferences</em></td>
</tr>
<tr>
<td width="45"><em>2a (i)</em></td>
<td width="360"><em>Effervescence that increases with heating </em><em>Green – yellow gas evolved</em></p>
<p><em>Gas changes moist blue litmus paper red and then bleaches it</em></td>
<td width="339"><em>Gas </em><em>evolved is chlorine D is an oxidizing Agent</em></p>
<p><em>Note: Chlorine is tied to either greenish – yellow Colour of gas or the Bleaching action of the gas</em></td>
</tr>
<tr>
<td width="45"><em> </em></p>
<p><em>(ii)</em></td>
<td width="360"><em>Colourless filtrate obtained brown ppt that is insoluble in</em></p>
<p><em>excess alkali formed</em></td>
<td width="339"><em>Fe<sup>3+</sup> ions present</em></td>
</tr>
<tr>
<td width="45"><em>b</em></td>
<td width="360"><em>Effervescence/bubbles/gas evolved gas has no effect on moist litmus paper. Produced</em></p>
<p><em>gas</em> <em>relights</em> <em>a glowing split</em></td>
<td width="339"><em>oxygen gas</em></p>
<p><em>D is a catalyst</em></p>
<p><em>D is probably MnO</em><em>2</em></td>
</tr>
<tr>
<td colspan="3" width="744"><em>N</em><em>o</em><em>t</em><em>e</em><em> In (a) (i) and (b) above credit ½ mark for ’gas’ given in place of effervescence /bubbles so long as properties of the gas given in the observation column are not contradictory, otherwise no mark for the ‘gas’</em></td>
</tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td width="56"><em>3</em></td>
<td width="297"><em>Observations</em></td>
<td width="391"><em>Inferences</em></td>
</tr>
<tr>
<td width="56"><em>a)</em></td>
<td width="297"><em>Melts to a colourless liquid. And burns with a smoky /sooty. Flame Note: accept melts on its own without Mentioning of colourless liquid. Unless contradictory colour given Accept –yellow sooty flame.</em></p>
<p><em>But not yellow flame</em></td>
<td width="391"><em>E is an unsaturated organic compound Note:- credit either E has</em></p>
<p><em>C</em><em>:</em> <em>H</em> <em>r</em><em>a</em><em>t</em><em>i</em><em>o</em> <em>o</em><em>r</em> <em>E</em> <em>c</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>s</em> <em>C</em><em>=</em><em>C</em> <em>o</em><em>r</em> <em>–</em><em>C</em><em>=</em><em>C</em><em>&#8211;</em> <em>i</em><em>n</em> <em>plac</em><em>e</em></p>
<p><em> </em></p>
<p><em>o</em><em>f</em> <em>‘’</em><em>u</em><em>n</em><em>s</em><em>a</em><em>t</em><em>u</em><em>r</em><em>a</em><em>t</em><em>e</em><em>d</em><em>’</em><em>’</em> <em>u</em><em>n</em><em>s</em><em>a</em><em>t</em><em>u</em><em>r</em><em>a</em><em>t</em><em>e</em><em>d</em> <em>t</em><em>i</em><em>e</em><em>d</em> <em>t</em><em>o</em> <em>s</em><em>m</em><em>o</em><em>ky flame Organic tied to melting &; burning</em></td>
</tr>
<tr>
<td width="56"><em>b)</em></td>
<td width="297"><em>Solid E does not dissolve readily solid E is sparingly partially soluble /solid E dissolves</em></p>
<p><em>H<sup>+</sup></em><em>(aq)</em> <em>ions</em><em> </em><em>present</em><em> </em><em>red.</em></td>
<td width="391"><em>E is an organic acid</em></p>
<p><em>E is an acidic compound hydrated hydrogen ions H<sup>+</sup></em><em>(aq) </em><em>ions present</em></td>
</tr>
<tr>
<td width="56"><em>c)</em></td>
<td width="297"><em>Solid E dissolved readily in aqueous</em></p>
<p><em>NaOH</em></td>
<td width="391"><em>E is organic acid/or E is a carboxylic acid</em></p>
<p><em>Or Acidic Compound / H<sup>+</sup> ions present.</em></td>
</tr>
<tr>
<td width="56"><em>d)(i)</em></td>
<td width="297"><em>Effervescence/bubbles/</em> <em>gas</em> <em>evolved colourless gas evolved extinguishes a burning / glowing</em></p>
<p><em>Splint changes moist blue litmus paper</em></p>
<p><em>Faint</em> <em>red / pink</em></td>
<td width="391"><em>Organic</em> <em>acid</em> <em>or</em> <em>carboxylic</em></p>
<p><em>aid or Acidic compound/ H<sup>+</sup> ions present</em></td>
</tr>
<tr>
<td width="56"><em>(ii)</em></td>
<td width="297"><em>A sweet smelling substance is formed / fruity smell/ pleasant smell</em></td>
<td width="391"><em>Ester is formed O</em></p>
<p><em>E is a carboxylic acid/ R – COOH / &#8211; C &#8211; OH alkanoic acid</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 1997 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><em> a).</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="123"><em>Time (min)</em></td>
<td width="39"><em>0</em></td>
<td width="39"><em>½</em></td>
<td width="39"><em>1</em></td>
<td width="52"><em>1 ½</em></td>
<td width="39"><em>2</em></td>
<td width="52"><em>2 ½</em></td>
<td width="39"><em>3</em></td>
<td width="52"><em>3 ½</em></td>
<td width="39"><em>4</em></td>
<td width="52"><em>4 ½</em></td>
<td width="38"><em>5</em></td>
<td width="48"><em>5 ½</em></td>
<td width="48"><em>6</em></td>
</tr>
<tr>
<td width="123"><em>Temperature </em><em>(<sup>0</sup>C)</em></td>
<td width="39"><em>20</em></td>
<td width="39"><em>20</em></td>
<td width="39"><em>20</em></td>
<td width="52"><em>X</em></td>
<td width="39"><em>25</em></td>
<td width="52"><em>29</em></td>
<td width="39"><em>31</em></td>
<td width="52"><em>31</em></td>
<td width="39"><em>33</em></td>
<td width="52"><em>34</em></td>
<td width="38"><em>34</em></td>
<td width="48"><em>34</em></td>
<td width="48"><em>34</em></td>
</tr>
</tbody>
</table>
<p><em>½ max for each entry </em><em>Maximum 5 marks</em></p>
<p><em>b). âT= 34 </em><em>–</em> <em>20</em> <em>= 14<sup>0</sup>C </em><em>1 mark</em></p>
<p><em>c). Energy change = 50 x 4.2 x 14 (1)</em></p>
<p><em>= 2940 Joules (1) 2 marks</em></p>
<p><em>d). Moles = <u>2940 </u> (1)</em></p>
<p> ;</p>
<p><em>323 x 1000</em></p>
<p><em>= 0.009 moles (1) 2 marks</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="263"> ;</td>
<td width="135"><strong><em>I</em></strong></td>
<td width="120"><strong><em>II</em></strong></td>
<td width="138"><strong><em>III</em></strong></td>
</tr>
<tr>
<td width="263"><em>Final burette reading (cm<sup>3</sup>)</em></td>
<td width="135"><em>32.8</em></td>
<td width="120"><em>15.9</em></td>
<td width="138"><em>31.9</em></td>
</tr>
<tr>
<td width="263"><em>Initial burette reading (cm<sup>3</sup>)</em></td>
<td width="135"><em>15.8</em></td>
<td width="120"><em>0.0</em></td>
<td width="138"><em>16.0</em></td>
</tr>
<tr>
<td width="263"><em>Volume of solution G used (cm<sup>3</sup>)</em></td>
<td width="135"><em>17.0</em></td>
<td width="120"><em>15.9</em></td>
<td width="138"><em>15.9</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>(6marks)</em></p>
<p><em>e). <u>15.9 + 15.9</u> ( ½ )</em></p>
<p><em>2</em></p>
<p><em>= 15.9cm<sup>3</sup> ( ½ ) 1 mark</em></p>
<p><em>f). <u>15.9 x 0.5</u></em></p>
<p><em>1000 (1)</em></p>
<p><em>= 0.008 moles (1) 2 marks</em></p>
<p><em>g). i). Moles of sulphuric acid = <u>0.008</u></em></p>
<p><em>2</em></p>
<p><em>= 0.004 moles ( ½ ) 1 mark</em></p>
<p><em>ii). 25cm<sup>3</sup> = 0.004 ( ½ )</em></p>
<p><em>100cm<sup>3</sup> = 0.016 moles ( ½ ) 1 mark</em></p>
<p> ;</p>
<ul>
<li><em>Total moles of F = 009 + 0.016 (½)</em></li>
</ul>
<p><em>= 0.025 moles ( ½ ) 1 mark</em></p>
<ul>
<li><em>50cm<sup>3</sup> = 025 moles </em><em>1000cm<sup>3</sup> = <u>0.025 x 1000</u> ( ½ )</em></li>
</ul>
<p><em>50</em></p>
<p><em>= 0.5M (½) 1 mark</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="124"><em>2</em></td>
<td width="356"><em>Observations</em></td>
<td width="249"><em>Inferences</em></td>
</tr>
<tr>
<td width="124"><em>(a)</em></td>
<td width="356"><em>Colourless</em> <em>gas that relights</em></p>
<p><em>a</em> <em>glowing</em> <em>splint (1)is produced</em></td>
<td width="249"><em>oxide present also allow chlorate nitrate,</em></p>
<p><em>permanganate</em> <em>(1)</em></td>
</tr>
<tr>
<td width="124"><em>(b) (i)</em></td>
<td width="356"><em>Residue turns black</em></p>
<p><em>Colourless solution after filtration 1 mark</em></td>
<td width="249"> ;</td>
</tr>
<tr>
<td width="124"><em>(ii)</em></td>
<td width="356"><em>White Ppt (½)</em></p>
<p><em>Soluble in excess ( ½ ) 3 marks</em></td>
<td width="249"><em>Al <sup>3+</sup> Pb <sup>2+</sup> or Zn<sup>2+</sup> (2)</em></td>
</tr>
<tr>
<td width="124"><em>(iii)</em></td>
<td width="356"><em>White Ppt ( ½ )</em></p>
<p><em>insoluble in excess ( ½ )</em></td>
<td width="249"><em>Pb<sup>2+</sup> or Al<sup>3</sup>&#8211; (1)</em></td>
</tr>
<tr>
<td width="124"><em>(iv)</em></td>
<td width="356"><em>White ppt</em></td>
<td width="249"><em>Pb</em><em>2+</em></td>
</tr>
<tr>
<td width="124"><em>3 a)</em></td>
<td width="356"><em>Decolourise (1)</em></td>
<td width="249"><em> </em></p>
<p> ;</p>
<p><em>&#8211; C = C (1) or –OH(1)</em></td>
</tr>
<tr>
<td width="124"><em>b)</em></td>
<td width="356"><em>Decolourise (1)</em></td>
<td width="249"><em> </em></p>
<p><em>&#8211; C = C present (1)</em></td>
</tr>
<tr>
<td width="124"><em>c)</em></td>
<td width="356"><em>Vigorous effervescence (1)</em></td>
<td width="249"><em>Solid M is an acid</em></p>
<p><em>or ROOH (1)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 1998 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><strong><em>Table 1</em></strong></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="333"> ;</td>
<td width="132"><strong><em>I</em></strong></td>
<td width="132"><strong><em>II</em></strong></td>
<td width="133"><strong><em>III</em></strong></td>
</tr>
<tr>
<td width="333"><em>Final burette reading</em></td>
<td width="132"><em>25.40</em></td>
<td width="132"><em>48.00</em></td>
<td width="133"><em>24.40</em></td>
</tr>
<tr>
<td width="333"><em>Initial burette reading</em></td>
<td width="132"><em>1.30</em></td>
<td width="132"><em>24.10</em></td>
<td width="133"><em>0.40</em></td>
</tr>
<tr>
<td width="333"><em>Volume of solution N(cm<sup>3</sup>)</em></td>
<td width="132"><em>24.10</em></td>
<td width="132"><em>23.90</em></td>
<td width="133"><em>24.0</em></td>
</tr>
</tbody>
</table>
<p><em>1 mark for accuracy; 1 table ; 1 use of decimal; 1 averaging; 1 final</em></p>
<p><em>Total marks 4 marks</em></p>
<p><em>Average of solution N = <u>24.10 + 23.90 + 24.0</u> ( ½ mark)</em></p>
<p><em>3</em></p>
<p><em>= 24.00cm<sup>3</sup> </em><em>1 mark</em></p>
<p><em>a). Concentration of solution N = <u>8.8</u></em></p>
<p><em>40 = 0.22M (½) 1 mark</em></p>
<p><em>b). 24.0 x 0.22 = 25M (½) M = <u>24 x 0.22</u></em></p>
<p><em>25</em></p>
<p><em>= 0.21M (½) 1 mark</em></p>
<p><strong><em>Table 2</em></strong></p>
<table>
<tbody>
<tr>
<td width="333"> ;</td>
<td width="132"><strong><em>I</em></strong></td>
<td width="132"><strong><em>II</em></strong></td>
<td width="133"><strong><em>III</em></strong></td>
</tr>
<tr>
<td width="333"><em>Final burette reading</em></td>
<td width="132"><em>12.50</em></td>
<td width="132"><em>12.50</em></td>
<td width="133"><em>29.40</em></td>
</tr>
<tr>
<td width="333"><em>Initial burette reading</em></td>
<td width="132"><em>0.00</em></td>
<td width="132"><em>0.0</em></td>
<td width="133"><em>17.0</em></td>
</tr>
<tr>
<td width="333"><em>Volume of solution N(cm<sup>3</sup>)</em></td>
<td width="132"><em>12.50</em></td>
<td width="132"><em>12.50</em></td>
<td width="133"><em>12.40</em></td>
</tr>
</tbody>
</table>
<p><em>1 mark for accuracy; 1 table ; 1 use of decimal; 1 averaging; 1 final</em></p>
<p><em>Total marks 4 marks</em></p>
<p><em>Average of solution N= <u>12.50 + 12.50 + 12.4</u> ( ½ mark)</em></p>
<p><em>3</em></p>
<p><em>= 12.47cm<sup>3</sup> ( ½ ) 1 mark</em></p>
<p><em>i). <u>12.47 x 0.22</u> (1)</em></p>
<p><em>1000 </em><em>= 0.00274 moles (1) 2 marks</em></p>
<p> ;</p>
<p><em>ii). 0. 00274 x 4 ( ½ )</em></p>
<p><em>= 0.00100 = ans a (i) x <sup>100</sup>/</em><em>25 </em><em>1 mark</em></p>
<ul>
<li><em><u>21 x 100</u></em></li>
</ul>
<p><em>1000 = ans (b) x <sup>100</sup>/</em><em>1000</em></p>
<p><em>= -0.021 moles ( ½ ) = ans a (iii) 1 mark</em></p>
<p> ;</p>
<p><em>iv). </em><em>0.02 – 0.0109 ( ½ )</em></p>
<p><em>= 0.01 ( ½ ) = ans (ii) &#8211; ans (ii)</em></p>
<p><em>= ans a (iv) 1 mark</em></p>
<p><em>v). 0.01 ( ½ ) = ans a (i) 2</em><em> </em><em>2</em></p>
<p><em>= 0.005 ( ½ ) = ans a (v) 1 mark</em></p>
<p><em>c). i). 72 x 0.005 ( ½ ) = 0.36g ( ½)</em></p>
<p><em>= 72 x ans a (iv) = ans b (i) ii). <u>0.36</u> x 100 ( ½ )</em></p>
<p><em>0.5</em></p>
<p><em>= ans <u>b (i) x 100</u></em></p>
<p><em>0.5</em></p>
<p><em>= 72 % ( ½ ) = ans (ii) 1 mark</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="47"><em>a).</em></td>
<td width="358"><em>Observations</em></td>
<td width="383"><em>Inferences</em></td>
</tr>
<tr>
<td width="47"> ;</td>
<td width="358"><em>Hissing sound</em></p>
<p><em>White fumes with choking smell that changes Moist blue litmus paper red and red litmus paper remains red</em></td>
<td width="383"><em>hydrated salt present</em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(3 marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="47"> ;</td>
<td width="358"><em>Colourless liquid condenses on cool parts of</em></p>
<p><em>test tube ( ½ )</em></td>
<td width="383"> ;</td>
</tr>
<tr>
<td width="47"><em>i).</em></td>
<td width="358"><em>white</em> <em>precipitate</em> <em>( ½ )</em></p>
<p><em>soluble in excess ( ½ )</em></td>
<td width="383"><em>Al </em><em>3+ </em><em>(aq) </em><em>Pb</em><em>2+ </em><em>(aq) </em><em>or Zn</em><em>(aq)2+</em></p>
<p><em>(2marks) for all three 1 mark for two) (3 marks)</em></td>
</tr>
<tr>
<td width="47"><em>ii).</em></td>
<td width="358"><em>white</em> <em>precipitate</em> <em>( ½ )</em></p>
<p><em>Insoluble in excess ( ½ )</em></td>
<td width="383"><em>Al<sup>3+</sup> ( ½ ) or Pb <sup>2+</sup> ( ½ )</em></p>
<p><em>OR Penalise ½ mark each contradiction (2 marks)</em></td>
</tr>
<tr>
<td width="47"><em>iii).</em></td>
<td width="358"><em>No white precipitate (1)</em></p>
<p><em>Reject no observable change</em></td>
<td width="383"><em>Absence of SO <sup>2-</sup></em><em>(aq) </em><em>CO <sup>2-</sup></em><em>(aq) </em><em>or SO <sup>2</sup> </em><em>(aq) </em><em>(1 mark</em></p>
<p><em>4 3 3 &#8211;</em></p>
<p><em>for all 3 correct ½ mark for 2 correct)Penalize ½ mark each contradiction. (2 marks)</em></td>
</tr>
<tr>
<td width="47"><em>iv).</em></td>
<td width="358"><em>White precipitate (1)</em></td>
<td width="383"><em>Cl</em><em>(aq) </em><em>present (2 marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>3.</em></p>
<table>
<tbody>
<tr>
<td width="45"><em>a).</em></td>
<td width="418"><em>Observations</em></td>
<td width="325"><em>Inferences</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="418"><em>Hissing /sound White fumes</em></p>
<p><em>with</em> <em>choking</em> <em>smell</em> <em>changing</em> <em>moist</em> <em>red litmus blue Melts into a colourless liquid</em></p>
<p><em>White sublimate Extinguishes a burning splint</em></p>
<p><em>(2</em> <em>marks</em> <em>for</em> <em>any</em> <em>four</em> <em>observations</em> <em>correct)</em></td>
<td width="325"><em>NH <sup>+</sup> (1)</em></p>
<p><em>4</em></p>
<p><em>Tied to litmus changing to blue</em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(3 marks)</em></td>
</tr>
<tr>
<td width="45"><em>b).</em></td>
<td width="418"><em>i). Turns from colourless to green &#8211; yellow </em><em>OR</em></p>
<p><em>pH 7 -8</em></td>
<td width="325"><em>Weekly alkaline (1)</em></p>
<p><em>Accept</em> <em>neutral (2 marks)</em></td>
</tr>
<tr>
<td width="45"> ;</td>
<td width="418"><em>ii)</em> <em>White precipitate</em></td>
<td width="325"><em>L is acidic</em></td>
</tr>
<tr>
<td width="45"><em>c)</em></td>
<td width="418">&#8211; <em>White ppt dissolves on warming</em></p>
<p>&#8211; <em>Effervescence</em></td>
<td width="325"><em>Carboxylic acid; COOH , H<sup>+</sup></em></p>
<p><em>Accept acidic compound.</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 1999 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><em>1 (a) (i) Table I</em></p>
<p><em>Table (T) = 2mks Decimal (D) = 1mk Accuracy (A) = 1mk</em></p>
<p><em>Principle of Av (PA) = 1mk Final answer (F) = 1mk</em></p>
<p> ;</p>
<p><em>Note: &#8211;</em> <em>3 titration consistent</em> <em>= 2mks</em></p>
<p><em>2 titration consistent = 1 ½ mks 2 titrations inconsistent 1mk</em></p>
<p><em>1 titration done = 1mk</em></p>
<p> ;</p>
<p><em>(ii) Average volume of solution E</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>(b) (i) No. of moles of basic compound G</em><em>2</em><em>X.10 H</em><em>2</em><em>O </em><em>No. of moles of E = <u>titre x 0.099</u></em></p>
<p><em>1000</em></p>
<p><em>No. of moles of F = <u>titre x 0.099 x ½</u></em></p>
<p><em>1000</em></p>
<p><em>= Ans (4 d.p)</em></p>
<p> ;</p>
<ul>
<li><em> of solution F in moles per litre </em><em>25cm<sup>3</sup> of F = Answer in (b) (i) 1000cm<sup>3</sup> of F = <u>Ans (b) (I) x 1000</u></em></li>
</ul>
<p><em>25</em></p>
<p><em>= Ans ( 3 dp)</em></p>
<p> ;</p>
<ul>
<li><em>Relative formula mass of basic compound G</em><em>2</em><em>10 H</em><em>2</em><em>O</em></li>
</ul>
<p><em><u>15.3 </u></em><em> = Molarity (Ans. (b) (ii) RFM</em></p>
<p><em>RFM = <u>15.3</u> = Ans</em></p>
<p><em>Ans in (b) (ii)</em></p>
<ul>
<li><em>Mass of 10 moles of H</em><em>2</em><em>O </em><em>= </em><em>10 (16 + 2) = 180 </em><em>2G + 180 + 155 = Ans (b) (iii)</em></li>
</ul>
<p><em>2G</em> <em>=</em> <em>Ans</em> <em>(b)</em> <em>(iii)</em> <em>&#8211;</em> <em>335 G = <u>Ans (b) (iii) – 335 </u></em></p>
<p><em>2</em></p>
<p><em>= Ans (± 0.5)</em></p>
<p> ;</p>
<ol start="2">
<li><strong><em>(a) Table III</em></strong></li>
</ol>
<p><em>T = 5 mks D = ½</em></p>
<p><em>A = 1mk (± 5 secs)</em></p>
<p><em>T = 1</em></p>
<p><em>(b)</em><em> </em><em>(i)</em><em> </em><em> </em><em>S = 1 mk</em> <em>C = 1 mk P = 1 mk</em></p>
<p> ;</p>
<ul>
<li><em>Showing on the graph = ½ mk Stating correct values ½ mk</em></li>
</ul>
<p><em>Expression t = <u>1</u> = ½ mk</em></p>
<p><em>Correct value</em></p>
<p><em>Rate at 7.5cm<sup>3</sup> (½ mk<strong>)</strong></em></p>
<ul>
<li><em>&#8211; Straight line (+ve gradient) = ½ mk</em></li>
</ul>
<p><em>&#8211; Rate of reaction increases as concentration <strong>OR</strong></em></p>
<p><strong><em>&#8211; </em></strong><em>Rate is directly proportional to concentration</em></p>
<p><em>&#8211; Straight line (+ ve gradient) = ½ mk</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="82"><em>3a).</em></td>
<td width="428"><em>Observations</em></td>
<td width="278"><em>Inferences</em></td>
</tr>
<tr>
<td width="82"> ;</td>
<td width="428">&#8211; <em>Light green solid turns brown</em></p>
<p>&#8211; <em>Colourless</em> <em>liquid/moisture/</em> <em>vapour condenses on cooler part of test tube</em></p>
<p><strong><em>&#8211; </em></strong><em>Pungent</em> <em>gas</em> <em>with</em> <em>irritating smell which changes moist blue litmus paper turns red</em></p>
<p><em>&#8211; Red litmus paper remains 2½mks)</em></td>
<td width="278">&#8211; <em>Fe<sup>2+</sup></em> <em>present</em></p>
<p>&#8211; <em>Hydrated salt/ water of </em><em>crystallization</em></td>
</tr>
<tr>
<td width="82"><em>bi).</em></td>
<td width="428"><em>&#8211; Green precipitate which is insoluble in excess</em></p>
<p><em>(1mk)</em></td>
<td width="278"><em>&#8211; Fe<sup>2+</sup> present (½ mk)</em></td>
</tr>
<tr>
<td width="82"><em>ii).</em></td>
<td width="428"><em>Yellow /brown/Reddish brown solution</em></td>
<td width="278"><em>&#8211; Fe<sup>2+</sup> Oxidised to F<sup>3+</sup></em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="82"> ;</td>
<td width="428"><em>Brown ppt. Insoluble in excess(1½ marks)</em></td>
<td width="278"> ;</td>
</tr>
<tr>
<td width="82"><em>iv)</em></td>
<td width="428"><em>&#8211;</em> <em>White precipitate</em></td>
<td width="278"><em>&#8211; SO <sup>2-</sup>, SO <sup>2-</sup>, CO <sup>2-</sup></em></p>
<p><em>3 4 3</em></td>
</tr>
<tr>
<td width="82"><em>II</em></td>
<td width="428"><strong><em>&#8211; </em></strong><em>White ppt remains</em></td>
<td width="278"><strong><em>&#8211; </em></strong><em>SO <sup>2-</sup></em></p>
<p><em>4</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 2000 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Table I</em></strong></p>
<ul>
<li><em>2 titrations consistent = 1 ½ marks</em></li>
<li><em>2 titration inconsistent = 1</em></li>
<li><em>1 titration = 1</em></li>
<li><em>Penalise maximum ( &#8211; ½ mark) for wrong amounts >; 0 or 1.0cm<sup>3</sup></em></li>
</ul>
<p> ;</p>
<p><strong><em>Table II</em></strong></p>
<p><em>Decimal</em> <em>(D)</em> <em>= ½ mark. Accuracy (A) = ½ mark</em></p>
<ul>
<li><em>School value ( SV) ± 2 cm<sup>3</sup></em></li>
<li><em>If more or less that value = 0 </em></li>
</ul>
<p> ;</p>
<p><em>(iii) I Conc. of Sodium carbonate in moles per litre (RFM Na</em><em>2</em><em>CO</em><em>3 </em><em>= 106)</em><em> </em><em><u>5.6 </u></em><em> = 0.05283M.</em></p>
<p><em>106</em></p>
<p><em>Answer given to at least 3 dp. If not, do not award for answer.</em></p>
<p><em>Wrong units ½ mark</em></p>
<p> ;</p>
<ul>
<li><em>Moles sodium carbonate in 25cm<sup>3</sup> of solution <u>25 x Ans I</u> = Ans</em></li>
</ul>
<p><em>1000</em></p>
<p><em>= <u>25 x 0.0528</u></em></p>
<p><em>1000</em></p>
<p><em>=</em> <em>0.0013207mol</em> <em>.</em> <em>(at</em> <em>least 4d.p)</em></p>
<p> ;</p>
<ul>
<li><em>Moles of hydrochloric </em><em>acid in total volume of solution used NaCO</em><em>3 </em><em>(aq) + 2 HCl 2NaCl (aq) + H</em><em>2</em><em>O </em><em>+ </em><em>CO</em><em>2</em><em>(g)</em></li>
</ul>
<p> ;</p>
<p><em>Ans (II) x 2 = Ans.</em></p>
<p> ;</p>
<ul>
<li><em>Concentration of hydrochloric acid in moles per litre </em><em>Total titre in (a) (ii) = Ans in III</em></li>
</ul>
<p><em>Therefore</em> <em>in 1000cm<sup>3</sup> =</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Table III</em></strong></p>
<p><em>Table (T) = 1 mark</em></p>
<ul>
<li><em>8 readings = 1 mk</em></li>
<li><em>6 readings = ½</em></li>
<li><em>Less than = 0 mk</em></li>
</ul>
<p><em>= <u>Ans III x 1000</u> = Ans 3 d.P Total titre</em></p>
<p> ;</p>
<ul>
<li><em>Values >; 40<sup>0</sup>C or <; 10<sup>0</sup>C ( from t = 0 to t = 1 ½ ) = &#8211; ½ mk Decimals (D) = ½ mk</em></li>
</ul>
<p><em>Accuracy (A)</em></p>
<ul>
<li><em>Compare with school values (SV) at t = 1 ½ if ± 2<sup>0</sup> c = ½ mk ; If not = 0mk Trend (T) = 1 mark</em></li>
<li><em>Trend &#8211; t = 0 to t = 1 ½ being constant = ½ mk OR</em></li>
<li><em>-t = ½ to t</em> <em>1 ½ being = ½ mk</em></li>
</ul>
<p> ;</p>
<p><em>2<sup>nd</sup> Trend &#8211; t = 2 ½ to t= 4 being constant and lower than between t = 0 to t = 1 ½ = ½ mk.</em></p>
<p> ;</p>
<p><strong><em>OR</em></strong></p>
<p><em>-t = 3 to t = 4 being constant and lower than between t = 0 to t = 1 ½ = ½ mk</em></p>
<p> ;</p>
<ul>
<li><em>The candidate should use the data obtained in table </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>â T</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Temp <sup>0</sup>C</em></strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong><em>Time (min)</em></strong></p>
<p><strong><em>Scale (S) ½ mk ; Labelling (L) = ½ mk ; Plotting (P) ½ mk ; Shape (S) = ½ mk</em></strong></p>
<p><strong> </strong></p>
<ul>
<li><em>See graph in b above of Temperature change â <strong>T</strong></em></li>
</ul>
<p><strong> </strong></p>
<ul>
<li><em>(i) of moles of solid G used. (K = 39.0, N = 14.0, O = 16) 1 mark RFM of KNO</em><em>3 </em><em>= 101</em></li>
</ul>
<p><em>Moles of G = <sup>3</sup> /</em><em>101 </em><em>= 0.0297( 4 d.p)</em></p>
<p><em>(ii) </em><em>Enthalpy of Solution â H</em><em>soln </em><em>and show sign of â H</em><em>soln </em><em>Heat absorbed = 30 x 4.2 x â T = Ans.</em></p>
<p><em>Heat absorbed by 1 mole = <u>Ans. Above</u> = Ans J/mol</em></p>
<p><em>Ans</em> <em>C</em></p>
<p><strong><em>Ans in Kj / mol</em></strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<table>
<tbody>
<tr>
<td width="77"><strong><em>3</em></strong></td>
<td width="456"><strong><em>Observation</em></strong></td>
<td width="266"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="77"><em>(a)</em></td>
<td width="456">&#8211; <em>Blue residue /solid ppt (1mk)</em></p>
<p>&#8211; <em>Colourless filtrate</em></td>
<td width="266"><em>Cu<sup>2+</sup> ions present</em></td>
</tr>
<tr>
<td width="77"><em>(b) (i)</em></td>
<td width="456"><strong><em>&#8211; </em></strong><em>White ppt (1mk)</em></p>
<p><em>&#8211; Dissolves in excess (1mk)</em></td>
<td width="266"> ;</td>
</tr>
<tr>
<td width="77"><em>(ii)</em></td>
<td width="456"><strong><em>&#8211; </em></strong><em>White ppt (1mk)</em></p>
<p><em>&#8211; Dissolves in excess (1mk)</em></td>
<td width="266"><em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em><em>,</em> <em>Z</em><em>n</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em> <em>p</em><em>r</em><em>e</em><em>s</em><em>e</em><em>n</em><em>t</em></td>
</tr>
<tr>
<td width="77"><em>(iii)</em></td>
<td width="456"><strong><em>&#8211; </em></strong><em>White ppt (½ mk)</em></p>
<p><em>&#8211; Insoluble in excess</em></td>
<td width="266">&#8211; <em>Pb<sup>2+</sup> </em><em>, </em><em>or Al<sup>3+</sup></em></p>
<p>&#8211; <em>Zn<sup>2+</sup> absent</em></td>
</tr>
<tr>
<td width="77"><em>(c)</em></td>
<td width="456"><em>&#8211; No white precipitate is formed</em></td>
<td width="266"><em>Al<sup>3+</sup> present</em></p>
<p><em>Pb<sup>2+</sup> absent</em></td>
</tr>
<tr>
<td width="77"><em>(d)</em></td>
<td width="456"><em>&#8211; White Precipitate</em></td>
<td width="266"><em>SO </em><em>2-</em></p>
<p><em>4</em></td>
</tr>
<tr>
<td width="77"><em>(e)</em></td>
<td width="456">&#8211; <em>Blue precipitate</em></p>
<p>&#8211; <em>Dissolve in excess to form deep blue solution</em></td>
<td width="266"><em>&#8211; Cu<sup>2+</sup> present</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 2001 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><em> (a) T = 1mk; AC = 1mk; FA = 1mk, D = 1mk; PA = 1mk</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Solution D of NaOH</em></li>
</ul>
<p><em>Moles of HCl = Moles of NaOH Molarity = <u>titre x 0.128 x 1000</u></em></p>
<p><em>1000 x 25</em></p>
<p><em>= Ans</em></p>
<p><strong><em>Solution A</em></strong></p>
<p><em>Molarity of A = <u>Ans in (a) above x 150</u></em></p>
<p><em>25</em></p>
<p><em>= Ans</em></p>
<p><strong><em>Or</em></strong></p>
<p><em>Ans in (a) above x 6 Procedure II, Table II</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>â T (<sup>0</sup>C)</em></strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<ul>
<li><em>From the graph determine the volume of sodium hydroxide, solution A required to neutralize the carboxylic acid</em></li>
<li><em>C</em><em>a</em><em>l</em><em>c</em><em>u</em><em>l</em><em>a</em><em>t</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>c</em><em>a</em><em>r</em><em>bo</em><em>x</em><em>y</em><em>l</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em> <em>u</em><em>s</em><em>e</em><em>d</em><em> for neutralization (= 20 &#8211; Ans (b) above)</em></li>
</ul>
<p><em>(d) (i) = A:C = Ans (b) : Ans (c) = 2: 1</em></p>
<p><em>(ii) Conc. In moles per litre of the carboxylic acid solution C <u>Moles of A = Ans. b (ii) x Ans (b) above</u></em></p>
<p><em>1000</em></p>
<p><em>Moles of C = ½ x moles of A</em></p>
<p> ;</p>
<p> ;</p>
<p><em><u>Molarity = ½ x Ans. b (ii) x Ans (b) x 1000</u></em></p>
<p><em>1000 x Ans (c)</em></p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"><em>2.</em></td>
<td width="404"><em>Observations</em></td>
<td width="310"><em>Inferences</em></td>
</tr>
<tr>
<td width="45"><em>(a)</em></td>
<td width="404">&#8211; <em>Cracking sound</em></p>
<p>&#8211; <em>Colourless</em> <em>liquid forms on cooler</em></td>
<td width="310">&#8211; <em>Hydrated salt</em></p>
<p>&#8211; <em>Neutral substance</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"> ;</td>
<td width="404"><em>Parts of test tube.</em></p>
<p><em>&#8211;</em> <em>NO effect on both red and blue litmus</em> <em>papers</em></td>
<td width="310"> ;</td>
</tr>
<tr>
<td width="45"><em> </em></p>
<p><em>b(i)</em></td>
<td width="404"><em>&#8211;</em> <em>White precipitate</em></td>
<td width="310"><em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em><em> Mg<sup>2+</sup> or Ba<sup>2+</sup> present</em></td>
</tr>
<tr>
<td width="45"><em> </em></p>
<p><em>(ii)</em></td>
<td width="404"><em>&#8211;</em> <em>White</em> <em>Precipitate</em></td>
<td width="310"><em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em><em> Mg<sup>2+</sup> or Ba<sup>2+</sup> present</em></p>
<p><em>OR Mg<sup>2+</sup> absent ½ mark</em></td>
</tr>
<tr>
<td width="45"><em> </em></p>
<p><em>(iii)</em></td>
<td width="404"><em>&#8211; White precipitate</em> <em>which dissolves on</em> <em>warming</em></td>
<td width="310"><em>Cl<sup>&#8211;</sup> present</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="38"><em>3</em></td>
<td width="360"><strong><em>Observations</em></strong></td>
<td width="354"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="38"><em>a</em></td>
<td width="360">&#8211; <em>Moist blue litmus paper changes to red</em></p>
<p>&#8211; <em>Moist</em> <em>on</em> <em>red</em> <em>litmus</em> <em>paper</em></td>
<td width="354"><em>&#8211; Acidic substance / or H<sup>+</sup> present</em></td>
</tr>
<tr>
<td width="38"><em>b</em></td>
<td width="360"><em>&#8211; Brown bromine water is not decolourised</em></td>
<td width="354"><em>C = C or C = C &#8211; <strong>absent</strong></em></p>
<p><em> </em></p>
<p><strong><em>OR</em></strong></p>
<p><em>Saturated</em> <em>compound</em> <em>present ½ C = C or &#8211; C = C &#8211; <strong>absent</strong></em></p>
<p><strong><em>OR</em></strong></p>
<p><em>Saturated</em> <em>compound</em> <em>present ½ Alkene / alkyne absent <strong>½</strong></em></td>
</tr>
<tr>
<td width="38"><em>c</em></td>
<td width="360"><em>Purple or KMnO</em><em>4 </em><em>is not decolorized Purple KMnO</em><em>4 </em><em>colour persists</em></td>
<td width="354"><em>Absence of C = C or R – OH absent</em></td>
</tr>
<tr>
<td width="38"><em>d</em></td>
<td width="360"><em>Effervescence or bubbles of gas</em></p>
<p><em>OR Fizzing / Hissing sound</em></td>
<td width="354"><em>Acidic Compound present</em></p>
<p><em>Or H<sup>+</sup> ions</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2002 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><em>a).</em></p>
<table>
<tbody>
<tr>
<td width="82"><em>Vol of A</em></p>
<p><em>H</em><em>2</em><em>O</em><em>2</em></td>
<td width="82"><em>Vol. H</em><em>2</em><em>O</em></td>
<td width="82"><em>Vol</em> <em>of</em> <em>B.</em></p>
<p><em>H</em><em>2</em><em>SO</em><em>4</em></td>
<td width="82"><em>Vol of C</em></p>
<p><em>Na</em><em>2</em><em>S</em><em>2</em><em>O</em><em>3</em></td>
<td width="82"><em>Vol of D</em></p>
<p><em>KI</em></td>
<td width="82"><em>Vol of E</em></p>
<p><em>Starch</em></td>
<td width="82"> ;</td>
<td width="65"><em>Time</em></p>
<p><em>(sec)</em></td>
<td width="99"><em><sup>1</sup></em><em>/</em><em>time</em> <em>sec</em></td>
</tr>
<tr>
<td width="82"><em>25</em></td>
<td width="82"><em>0</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>2</em></td>
<td width="82"> ;</td>
<td width="65"><em>18</em></td>
<td width="99"><em>56&#215;10<sup>-2</sup></em></td>
</tr>
<tr>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>2</em></td>
<td width="82"> ;</td>
<td width="65"><em>22.5</em></td>
<td width="99"><em>4.4&#215;10<sup>-2</sup></em></td>
</tr>
<tr>
<td width="82"><em>15</em></td>
<td width="82"><em>10</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>2</em></td>
<td width="82"> ;</td>
<td width="65"><em>29</em></td>
<td width="99"><em>3.4&#215;10<sup>-2</sup></em></td>
</tr>
<tr>
<td width="82"><em>10</em></td>
<td width="82"><em>15</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>2</em></td>
<td width="82"> ;</td>
<td width="65"><em>43.5</em></td>
<td width="99"><em>2.3X10<sup>-2</sup></em></td>
</tr>
<tr>
<td width="82"><em>5</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>20</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>5</em></td>
<td width="82"><em>2</em></td>
<td width="82"><em>90.5</em></td>
<td width="65"><em>90.5</em></td>
<td width="99"><em>1.1X10<sup>-2</sup></em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>b). ½ for each axis</em></p>
<p><em>2 marks for plotting 5p/s correctly</em></p>
<p><em>1 mark for best straight line </em><em>4 marks</em></p>
<p><em>c). <sup>1</sup>/</em><em>time </em><em>= 1.7 x 10<sup>-2(I)</sup></em></p>
<p><em>Time = 58.82sec 2 marks</em></p>
<ul>
<li><em>Rate</em> <em>decreases</em> <em>–</em> <em>with</em> <em>the</em> <em>decrease</em> <em>in the concentration of hydrogen peroxide</em></li>
</ul>
<p><em>2</em> <em>marks</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="47"><strong><em>2</em></strong></td>
<td width="345"><strong><em>Observations</em></strong></td>
<td width="407"><strong><em>inferences</em></strong></td>
</tr>
<tr>
<td width="47"><em>a</em></td>
<td width="345"><em>Shiny metal is coated with a Black/grey substance (½)Colourless filtrate obtained (½)</em></td>
<td width="407"><em>metal G is more reactive </em><em>than metal whose ions are In solution F (I)</em></p>
<p><em>OR</em> <em>displacement</em> <em>reaction</em></p>
<p><em>Occurred</em></td>
</tr>
<tr>
<td width="47"><em>b</em></td>
<td width="345"><em>No white ppt<sup>(1)</sup> Or</em></p>
<p><em>Rej no observable change</em></td>
<td width="407"><em>Absence of</em></p>
<p><em>SO <sup>2-</sup> CO <sup>2-</sup> or SO <sup>2-</sup>(ions) </em><em>4 3</em><em> </em><em>3</em></p>
<p><em>award</em> <em>2</em> <em>marks</em> <em>for all 3</em></p>
<p><em>Award 1 mark for 2 Award ½ mark for 1</em></td>
</tr>
<tr>
<td width="47"><em>c</em></td>
<td width="345"><em>White PPt (½)</em></p>
<p><em>Soluble in excess (½)</em></td>
<td width="407"><em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em><sup>,</sup></em> <em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em> <em>o</em><em>r</em> <em>Z</em><em>n</em><em><sup>2</sup></em><em><sup>+</sup></em> <em>a</em><em>s</em> <em>i</em><em>n</em> <em>(</em><em>b</em><em>)</em> <em>a</em><em>bov</em><em>e</em><em> 3 marks</em></td>
</tr>
<tr>
<td width="47"><em>d</em></td>
<td width="345"><em>White PPt (½) which dissolves on boiling (I)</em></td>
<td width="407"><em>Pb<sup>2+</sup> (I) present</em></p>
<p><em>2 ½ marks</em></td>
</tr>
<tr>
<td width="47"><em>e</em></td>
<td width="345"><em>White PPt (½)</em></p>
<p><em>colourless filtrate ( ½ )</em></td>
<td width="407"><em>Pb<sup>2+</sup> confirmed (I)</em></p>
<p><em>2</em> <em>marks</em></td>
</tr>
<tr>
<td width="47"><em>f</em></td>
<td width="345"><em>White PPt (I)</em></p>
<p><em>Soluble in excess (I)</em></td>
<td width="407"><em>Zn<sup>2+</sup> present (I) 3 marks</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="47"><strong><em>3</em></strong></td>
<td width="345"><strong><em>Observations</em></strong></td>
<td width="407"><strong><em>inferences</em></strong></td>
</tr>
<tr>
<td width="47"><em>a</em></td>
<td width="345"><em>Melts ( ½ ) into colourless liquid ( ½ ) burns with a smoky flame (1)</em></td>
<td width="407"><em>unsaturated organic </em><em>compound</em></p>
<p><em>accept long chain hydrocarbon or aromatics</em></td>
</tr>
<tr>
<td width="47"><em>b(i)</em></td>
<td width="345"><em>The purple KMnO</em><em>4 </em><em>decolourised/changes to</em></p>
<p><em>colourless. The colour of KmnO</em><em>4 </em><em>changes </em><em>from purple to colourless</em> <em>(I) </em><em>3 marks</em></td>
<td width="407"><em>Could be an alcohol or unsaturated compound (I) R – OH , &#8211; C = C &#8211; C = C &#8211; 2 marks</em></td>
</tr>
<tr>
<td width="47"><em>(ii)</em></td>
<td width="345"><em>Brown bromine is decolorized/ changes t</em></p>
<p><em>colourless Decolourised (I)</em></td>
<td width="407"><em>Unsaturated (I) compound 2 marks</em></td>
</tr>
<tr>
<td width="47"><em>(iii)</em></td>
<td width="345"><em>Turns orange ( ½ )</em></p>
<p><em>pH = 5 ½ 2 marks</em></td>
<td width="407"><em>compound is a weak acid (I) 2 marks</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2003 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><em>(a) Volume of solution P = 0cm<sup>3</sup></em></li>
</ol>
<p><em>(b) Average volume of solution P <u>15.0 + 15.0</u> = 15.0cm<sup>3</sup></em></p>
<p><em>2</em></p>
<p><em>(c) <u>15.0 x 0.02</u> = 0.0003 moles</em></p>
<p><em>1000</em></p>
<p><em>(d) gdm<sup>3</sup> = <u>4.18 x 1000</u></em></p>
<p><em>250</em></p>
<p><em>= 16.72gdm<sup>3</sup></em></p>
<p><em><u>16.72</u></em> <em>from (d) above = 0.060M 278</em></p>
<p><em>(e) Moles of Q in 25.0cm<sup>3</sup></em></p>
<p> ;</p>
<p><em><u>0.06 x 25</u></em> <em>= 0.0015 moles</em></p>
<p><em>1000</em></p>
<p> ;</p>
<ul>
<li><em>003 moles rxts 0.0015 of Q 1 mole = <u>1 x 0.0015</u></em></li>
</ul>
<p><em>0.0003</em></p>
<p><em>=</em> <em>5 moles</em></p>
<p> ;</p>
<ol start="2">
<li><strong><em>Procedure I</em></strong>
<ul>
<li><em>Table</em> <em>II</em> <em>Table</em> <em>&#8211;</em> <em>½</em> <em>mk</em> <em>,</em> <em>Decimal</em> <em>–</em> <em>½ mk ; Accuracy = ½ mk</em></li>
<li><em>Final temp – Initial temp</em></li>
<li><em>(i) Heat change when H</em><em>2</em><em>A dissolve in water (assume heat capacity of </em><em>the solution is 2)</em></li>
</ul>
</li>
</ol>
<p><em>30 x 4.2 x â T = Ans in J. Or <u>30 x 4.2 x âT</u> = kJ</em></p>
<p><em>1000</em></p>
<p><em>(ii) Number of moles of acid used (RFM of H</em><em>2</em><em>A is 126)</em><em> </em><em><u>1.9</u></em> <em>= 0.01508 moles</em></p>
<p><em>126</em></p>
<ul>
<li><em>Molar heat of solution âH</em><em>1 </em><em>soln of the acid H</em><em>2</em><em>A</em></li>
</ul>
<p> ;</p>
<p><em>â H <u>c (i)</u> = J/mole Or Kj/mole c (ii)</em></p>
<p><strong><em>Procedure II</em></strong></p>
<p><em>(a) and (b) as in procedure 1</em></p>
<ul>
<li><em>(i) Heat (heat capacity 4.2 J/g/<sup>0</sup>C and density 1 g/cm<sup>3</sup> 60 x 4.2 x â T = Ans in J or kJ</em></li>
<li><em>Number of moles of the acid H</em><em>2</em><em>A used</em><em><u>5 x 30</u></em> <em>= 0.015</em></li>
</ul>
<p><em>1000</em></p>
<ul>
<li><em>Heat of reaction â H</em><em>2 </em><em>of one mole of the acid H</em><em>2</em><em>A with Sodium hydroxide</em></li>
</ul>
<p> ;</p>
<p><em>â H</em><em>2 </em><em>= <u>C (i) </u> = Ans</em></p>
<p><em>C (ii)</em></p>
<p> ;</p>
<p> ;</p>
<p><em>Or</em></p>
<p><em><u>60 x 4.2 x â T</u></em> <em>= Ans. (in J or KJ) C (ii)</em></p>
<p> ;</p>
<ul>
<li><em>â H</em><em>3 </em><em>for the reaction H</em><em>2</em><em>A (s) + 2 OH<sup>&#8211;</sup> (aq) 2H</em><em>2</em><em>O</em><em> </em><em>(l)</em><em> </em><em>+</em><em> </em><em>A<sup>2-</sup> (aq)</em></li>
</ul>
<p><em>â H</em><em>3 </em><em>= â H</em><em>2 </em><em>+ â H</em><em>2 </em><em>= Ans (-ve kJ /mole)</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"><strong><em>3</em></strong></td>
<td width="330"><strong><em>Observations</em></strong></td>
<td width="339"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="45"><em>(a)</em></td>
<td width="330"><em>Colourless</em> <em>solution formed</em></td>
<td width="339"><em>C</em><em>o</em><em>l</em><em>o</em><em>u</em><em>r</em><em>e</em><em>d</em> <em>i</em><em>o</em><em>n</em><em>s</em> <em>a</em><em>b</em><em>s</em><em>e</em><em>n</em><em>t</em><em> e.g Cu<sup>2</sup>+ , Fe<sup>2</sup><sup>+,</sup> or Fe</em></p>
<p><em><sup>3+</sup></em> <em>absent</em></td>
</tr>
<tr>
<td width="45"><em>(b)</em></td>
<td width="330"><em>No white precipitate formed</em></td>
<td width="339"><em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em>’</em> <em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em><em>,</em> <em>Z</em><em>n</em><em><sup>2</sup></em><em><sup>+</sup></em> <em><sup>,</sup></em> <em>M</em><em>g</em><em><sup>2</sup></em><em><sup>+</sup></em><em> Or Ca<sup>2+</sup> absent</em></td>
</tr>
<tr>
<td width="45"><em>(c)</em></td>
<td width="330"><em>White precipitate formed</em></td>
<td width="339"><em>C</em><em>l</em><em><sup>&#8211;</sup></em><em>,</em> <em>S</em><em>O</em> <em><sup>2</sup></em><em><sup>&#8211;</sup></em><em>,</em> <em>S</em><em>O</em> <em><sup>2</sup></em><em><sup>&#8211;</sup></em> <em>,</em><em> or CO <sup>2+</sup> present</em></p>
<p><em>4 3 3</em></td>
</tr>
<tr>
<td width="45"><em>(d)</em></td>
<td width="330"><em>White precipitate formed dissolves in HCl</em></p>
<p><em>(aq)</em></td>
<td width="339"><em>SO <sup>2-</sup> or</em> <em>CO <sup>2-</sup> present</em></p>
<p><em>3 3</em></td>
</tr>
<tr>
<td width="45"><em>(e)</em></td>
<td width="330"><em>Purple KMnO</em><em>4 </em><em>is (aq) decolorized or </em><em>changes to colourless</em></td>
<td width="339"><em>SO <sup>2-</sup> present Or Reducing</em></p>
<p><em>3</em></td>
</tr>
<tr>
<td width="45"><em>(f)</em></td>
<td width="330"><em>Green</em> <em>solution</em> <em>formed</em> <em>OR</em> <em>Colour</em></p>
<p><em>changes Orange to green</em></td>
<td width="339"><em>SO <sup>2-</sup> present Or Reducing</em></p>
<p><em>3</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 2005 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><em>1<strong>. </strong>(a)</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="165"><em>Time (min)</em></td>
<td width="60"><em>0</em></td>
<td width="60"><em>½</em></td>
<td width="60"><em>1</em></td>
<td width="58"><em>1 ½</em></td>
<td width="60"><em>2</em></td>
<td width="60"><em>2 ½</em></td>
<td width="60"><em>3</em></td>
<td width="54"><em>3 ½</em></td>
</tr>
<tr>
<td width="165"><em>Temp (<sup>0</sup>C)</em></td>
<td width="60"><em>82</em></td>
<td width="60"><em>73</em></td>
<td width="60"><em>69</em></td>
<td width="58"><em>68</em></td>
<td width="60"><em>68</em></td>
<td width="60"><em>68</em></td>
<td width="60"><em>66</em></td>
<td width="54"><em>65</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>1</em> <em>Mark</em> <em>fore</em> <em>the</em> <em>two axis</em></p>
<p><em>1 mark for all points correctly plotted</em></p>
<p><em>1 mark for plot occupying ¾ of the grid provided</em></p>
<p> ;</p>
<ul>
<li><em>68<sup>0</sup>C</em></li>
</ul>
<p><em>2</em></p>
<table>
<tbody>
<tr>
<td colspan="2" width="424"> ;</td>
<td width="120"><em>I</em></td>
<td width="122"><em>II</em></td>
</tr>
<tr>
<td colspan="2" width="424"><em>Initial temperature of solution KT</em><em>1 </em><em>(<sup>0</sup>C)</em></td>
<td width="120"><em>26</em></td>
<td width="122"><em>26</em></td>
</tr>
<tr>
<td colspan="2" width="424"><em>Initial temperature of solution L T</em><em>2 </em><em>(<sup>0</sup>C)</em></td>
<td width="120"><em>25</em></td>
<td width="122"><em>26</em></td>
</tr>
<tr>
<td colspan="2" width="424"><em>Highest temperature of mixture T</em><em>3 </em><em>(<sup>0</sup>C)</em></td>
<td width="120"><em>30.5</em></td>
<td width="122"><em>31</em></td>
</tr>
<tr>
<td colspan="2" width="424"><em>Average initial temperature (<sup>0</sup>C)</em></td>
<td width="120"><em>25.5</em></td>
<td width="122"><em>26</em></td>
</tr>
<tr>
<td colspan="2" width="424"><em>Change</em> <em>in</em> <em>temperature</em> <em>âT (<sup>0</sup>C)</em></td>
<td width="120"><em>5</em></td>
<td width="122"><em>5</em></td>
</tr>
<tr>
<td width="49"> ;</td>
<td width="375"><em> </em></p>
<p><em>Table 1</em></p>
<p><em>½ mark for each entry</em></td>
<td colspan="2" width="242"><em>(5 marks)</em></td>
</tr>
<tr>
<td width="49"><em>a).</em></td>
<td width="375"><em>Average <u>5 + 5</u> = 5</em></td>
<td colspan="2" width="242"> ;</td>
</tr>
<tr>
<td width="49"> ;</td>
<td width="375"><em>2</em></td>
<td colspan="2" width="242"><em>(1 mark)</em></td>
</tr>
<tr>
<td width="49"><em>b).</em></td>
<td width="375"><em>Heat change = 50 x 4.2 x 5 (1)</em></td>
<td colspan="2" width="242"> ;</td>
</tr>
<tr>
<td width="49"> ;</td>
<td width="375"><em>= 1050 Joules</em></td>
<td colspan="2" width="242"><em>(2 marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>Number of moles of acid L <u>1050</u></em></li>
</ul>
<p><em>143.4 x 1000</em></p>
<p><em>=</em> <em>0.0078125 </em><em>(2 marks)</em></p>
<p><em>d). 25cm<sup>3</sup> </em><em>= 0.0078125 moles</em></p>
<p><em>=</em> <em><u>0.0078125</u></em> <em><u>x</u></em> <em><u>1000</u></em></p>
<p><em>25</em></p>
<p><em>= 0.3125M </em><em>(2 marks)</em></p>
<p> ;</p>
<p><em>e). </em><em>Relative formula mass of acid L 60 = 0.3125 – (L)</em></p>
<p><em>R.F.M</em></p>
<p><em>R.F.M = 192 (l)</em></p>
<p><em>(2 marks)</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"><strong><em>3</em></strong></td>
<td width="330"><strong><em>Observations</em></strong></td>
<td width="339"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="45"><em>(a)</em></p>
<p><em>(i)</em></td>
<td width="330"><em>Cracking sound Colourless liquid</em></p>
<p><em>Gas with pungent smell Colourless gas is produced which</em></p>
<p><em>changes moist red litmus paper blue (2 marks for four correct observations</em></td>
<td width="339"><em>N</em> <em>is</em> <em>hydrated</em></p>
<p><em>a basic gas is formed ( ½ mark for each) (correct inference)</em></td>
</tr>
<tr>
<td width="45"><em>(i)</em></td>
<td width="330"><em>White Ppt (½)</em></td>
<td width="339"><em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em> <em>o</em><em>r</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em> <em>i</em><em>o</em><em>n</em><em>s</em><em>,</em> <em>M</em><em>g</em><em><sup>2</sup></em><em>+</em><em> ions present</em></td>
</tr>
<tr>
<td width="45"><em>(ii)</em></td>
<td width="330"><em>No white precipitate is formed</em></td>
<td width="339"><em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em><em> ion ; Mg<sup>2+</sup> ion present; Pb<sup>2</sup><sup>+</sup> ions</em></p>
<p><em>absent</em></td>
</tr>
<tr>
<td width="45"><em>(iii)</em></td>
<td width="330"><em>White Ppt</em></td>
<td width="339"><em>SO <sup>2-</sup>, SO <sup>2-</sup> CO <sup>2-</sup> Cl<sup>&#8211;</sup> 1 mark for two (2</em></p>
<p><em>4 3 3</em></p>
<p><em>marks)</em></td>
</tr>
<tr>
<td width="45"><em>(iv)</em></td>
<td width="330"><em>White Ppt</em></td>
<td width="339"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"> ;</td>
<td width="330"><em>persists (l)</em></td>
<td width="339"><em>2</em></p>
<p><em>S</em><em>O</em><em>4</em><em> </em><em>&#8211;</em><em> ion present –(l) (2 marks)</em></td>
</tr>
<tr>
<td width="45"><em>b(i)</em></td>
<td width="330"><em>A</em> <em>clear</em> <em>colourless</em> <em>solution</em> <em>(l)</em></td>
<td width="339"><em>Salt is soluble (l) </em><em>(2 marks) Acid solution is formed ( 1)</em></td>
</tr>
<tr>
<td width="45"><em>(ii)</em></td>
<td width="330"><em>No effervescence (l)</em></td>
<td width="339"><em>(H<sup>+</sup> absent (l) (2 marks)</em></td>
</tr>
<tr>
<td width="45"><em>(iii)</em></td>
<td width="330"><em>White solid formed (l)</em></p>
<p><em>Slightly soluble in excess ( ½ ) On addition of NaHCO</em><em>3</em></p>
<p><em>There</em> <em>is</em> <em>effervescence</em> <em>( ½ ) Colourless gas ( ½ )</em></p>
<p><em>Give maximum 2 marks for observations) ( 3 marks)</em></td>
<td width="339"><em>Acid solution is formed ( 1)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2006 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><strong><em>Table</em></strong> <strong><em>1</em></strong> <em>(i)</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="197"><em>Volume of water in the boiling tube (cm<sup>3</sup>)</em></td>
<td width="223"><em>Temperature at which crystals of solid A first</em></p>
<p><em>appear ( <sup>0</sup>C )</em></td>
<td width="195"><em>Solubility of solid A </em><em>(g/100g water</em></td>
</tr>
<tr>
<td width="197"><em>4</em></td>
<td width="223"><em>66 &#8211; 67</em></td>
<td width="195"><em>112.5</em></td>
</tr>
<tr>
<td width="197"><em>6</em></td>
<td width="223"><em>56 – 57</em></td>
<td width="195"><em>75</em></td>
</tr>
<tr>
<td width="197"><em>8</em></td>
<td width="223"><em>49 – 50</em></td>
<td width="195"><em>56</em></td>
</tr>
<tr>
<td width="197"><em>10</em></td>
<td width="223"><em>44 – 45</em></td>
<td width="195"><em>45</em></td>
</tr>
<tr>
<td width="197"> ;</td>
<td width="223"> ;</td>
<td width="195"> ;</td>
</tr>
</tbody>
</table>
<p><em>1 mark for temp value within range</em></p>
<p><em>½ mark for each value ± 2<sup>0</sup>C</em></p>
<p><em>½ mark for each value of solubility correctly calculated</em></p>
<p><em>(ii) &#8211; S – 1; P – 1; C – 1</em></p>
<p> ;</p>
<p><em>(iii) 63 ± 0.5 <sup>0</sup>C</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="297"> ;</td>
<td width="93"><em>I</em></td>
<td width="90"><em>II</em></td>
<td width="135"><em>III</em></td>
</tr>
<tr>
<td width="297"><em>Final burette reading</em></td>
<td width="93"><em>24.40</em></td>
<td width="90"><em>48.60</em></td>
<td width="135"><em>26.20</em></td>
</tr>
<tr>
<td width="297"><em>Initial burette</em> <em>reading</em></td>
<td width="93"><em>0.00</em></td>
<td width="90"><em>24.40</em></td>
<td width="135"><em>26.40</em></td>
</tr>
<tr>
<td width="297"><em>Volume of solution B used (cm<sup>3</sup>)</em></td>
<td width="93"><em>24.40</em></td>
<td width="90"><em>24.40</em></td>
<td width="135"><em>24.20</em></td>
</tr>
</tbody>
</table>
<p><strong><em>(Award for each titre value ± of the teachers value</em></strong></p>
<p><em>I <u>24.20 + 24.20</u> = 24.20cm<sup>3</sup></em></p>
<p><em>2</em></p>
<p><em>II <u>0.06 x 24.20</u> = 1.45 x 10<sup>3</sup> moles</em></p>
<p><em>1000</em></p>
<p><em>III 1.45 x 10<sup>-3</sup> x 5 = 3.63 x 10<sup>-3</sup> moles</em></p>
<p><em>2</em></p>
<p> ;</p>
<p><em>IV 3.63 x 10<sup>-3</sup> x 10</em></p>
<p><em>= 3.63 x 10<sup>-2</sup> moles</em></p>
<p><em>= <u>4.5</u></em></p>
<p><em>x 10<sup>-2</sup></em></p>
<p><em>= 124</em></p>
<p> ;</p>
<p><em>(iii) DxH</em><em>2</em><em>O</em></p>
<p><em>90 + 18 x = 124</em></p>
<p><em>X = 34</em></p>
<p><em>= 1.9</em></p>
<p><em>= 2</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>2</em></strong><em>.</em></p>
<table>
<tbody>
<tr>
<td width="368"><em>Observations</em></td>
<td width="399"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="368"><em> </em></p>
<p><em>(a) Colourless liquid condenses on cool parts of test tube. White solid remains</em></td>
<td width="399"><em> </em></p>
<p><em>Probably hydrated</em> <em>salt/ compound</em> <em>(1) present</em></td>
</tr>
<tr>
<td width="368"><em>(b) &#8211; Colourless filtrate ( ½ )</em></p>
<p><em>&#8211; White residue</em></td>
<td width="399"><em>Compound sparingly soluble</em></td>
</tr>
<tr>
<td width="368"><em>(i) Solution turns pink</em></td>
<td width="399"><em>C</em><em>o</em><em>m</em><em>poun</em><em>d</em><em> </em><em>i</em><em>s</em><em> </em><em>ba</em><em>s</em><em>i</em><em>c</em><em> OH<sup>&#8211;</sup>, HCO</em><em>3</em> <em>o</em><em>r</em><em> </em><em>C</em><em>O</em><em> </em><em><sup>2</sup></em><em><sup>&#8211;</sup></em><em> present</em></p>
<p><em>3</em></p>
<p><em>OH<sup>&#8211;</sup> present or HCO</em><em>3 </em><em>or CO <sup>2-</sup> absent.</em></p>
<p><em>3</em></td>
</tr>
<tr>
<td width="368"><em>(ii) No effervesnce</em></td>
<td width="399"> ;</td>
</tr>
<tr>
<td width="368"><em> </em></p>
<p><em>(iii) White ppt formed</em></td>
<td width="399"><em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em> <em>,</em> <em>B</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em> present (2mks for all three 1 mk for 2</em></td>
</tr>
<tr>
<td width="368"><em>(iv) No white ppt</em></td>
<td width="399"><em>Ba<sup>2+</sup> present or Ca<sup>2+</sup> or Pb<sup>2+</sup></em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>3.</em></strong></p>
<table>
<tbody>
<tr>
<td width="368"><em>(a) Burns with luminous ( yellow, smoky) </em><em>flame</em></td>
<td width="399"><em>Unsaturated compound OR Long chain hydrocarbon</em></p>
<p><em>&#8211; C = C &#8211; / &#8211; C = C &#8211; Or Hydrocarbon with</em></td>
</tr>
<tr>
<td width="368"> ;</td>
<td width="399"><em>high C: H ratio Or aromatic cpd</em></p>
<p><em>&#8211; NB – Each these tied to burning with smoky/sooty flame</em></td>
</tr>
<tr>
<td width="368"><em>(b) (i) Purple Potassium manganate (VII) is Decolourised (changes from purple to colourless</em></td>
<td width="399"><em>Alkene</em> <em>or alcohol present</em></p>
<p><em>&#8211; C = C &#8211; or R – OH</em></td>
</tr>
<tr>
<td width="368"><em>(ii) Brown bromine water is decolorized (</em></p>
<p><em>Changes from red to Colourless)</em></td>
<td width="399"><em>Alkene present // &#8211; C = C – present</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong><em>NOVEMBER 2007 MARK SCHEME</em></strong></p>
<p> ;</p>
<ol>
<li><em> a).</em></li>
</ol>
<table>
<tbody>
<tr>
<td width="285"> ;</td>
<td width="105"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="99"><em>III</em></td>
</tr>
<tr>
<td width="285"><em>Final burette reading</em></td>
<td width="105"><em>21.8</em></td>
<td width="105"><em>21.6</em></td>
<td width="99"><em>43.6</em></td>
</tr>
<tr>
<td width="285"><em>Initial burette reading</em></td>
<td width="105"><em>0.0</em></td>
<td width="105"><em>0.0</em></td>
<td width="99"><em>22.0</em></td>
</tr>
<tr>
<td width="285"><em>Volume of D used (cm<sup>3</sup>)</em></td>
<td width="105"><em>21.8</em></td>
<td width="105"><em>21.6</em></td>
<td width="99"><em>21.6</em></td>
</tr>
</tbody>
</table>
<p><em>(3 marks)</em></p>
<p><em>i). <u>21.6 + 21.6</u></em></p>
<p><em>2 = 21.6cm<sup>3</sup> (1 mark)</em></p>
<ul>
<li><em>F.M of Na</em><em>2</em><em>CO</em><em>3 </em><em>=</em><em> </em><em>106</em></li>
</ul>
<p><em>Conc. <u>8</u> = 0.075M 106</em></p>
<ul>
<li><em>Moles of Na</em><em>2</em><em>CO</em><em>3 </em><em><u>25</u></em><em><u> </u></em><em><u>x</u></em><em><u> </u></em><em><u>075M</u></em><em> </em><em>1000</em></li>
</ul>
<p><em>= 0.001875</em></p>
<p><em>Moles of H</em><em>2</em><em>SO</em><em>4 </em><em>=</em><em> </em><em>0.001875</em></p>
<p><em>Conc.</em><em> </em><em>of</em><em> </em><em>H</em><em>2</em><em>SO</em><em>4 </em><em>= </em><em><u>0.001875</u></em><em> </em><em>x 1000 </em><em>21.6</em></p>
<p><em>= 0.0868M</em></p>
<p> ;</p>
<p> ;</p>
<p><em>iv). 0.0868 x 10 = 0.868M</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="553">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="359"><em>Test-tube number</em></td>
<td width="53"><em>1</em></td>
<td width="53"><em>2</em></td>
<td width="59"><em>3</em></td>
<td width="53"><em>4</em></td>
<td width="53"><em>5</em></td>
<td width="54"><em>6</em></td>
</tr>
<tr>
<td width="359"><em>Volume of solution A (cm<sup>3</sup>)</em></td>
<td width="53"><em>2</em></td>
<td width="53"><em>4</em></td>
<td width="59"><em>6</em></td>
<td width="53"><em>8</em></td>
<td width="53"><em>6</em></td>
<td width="54"><em>4</em></td>
</tr>
<tr>
<td width="359"><em>Volume of solution C (cm<sup>3</sup>)</em></td>
<td width="53"><em>14</em></td>
<td width="53"><em>12</em></td>
<td width="59"><em>10</em></td>
<td width="53"><em>8</em></td>
<td width="53"><em>10</em></td>
<td width="54"><em>12</em></td>
</tr>
<tr>
<td width="359"><em>Initial temperature of solution C (<sup>0</sup>C)</em></td>
<td width="53"><em>20.5</em></td>
<td width="53"><em>20.5</em></td>
<td width="59"><em>20.5</em></td>
<td width="53"><em>20.5</em></td>
<td width="53"><em>20.5</em></td>
<td width="54"><em>20.5</em></td>
</tr>
<tr>
<td width="359"><em>Highest temperature of mixture (<sup>0</sup>C)</em></td>
<td width="53"><em>23</em></td>
<td width="53"><em>25.5</em></td>
<td width="59"><em>28.0</em></td>
<td width="53"><em>29.5</em></td>
<td width="53"><em>26.5</em></td>
<td width="54"><em>24.5</em></td>
</tr>
<tr>
<td width="359"><em>Change</em> <em>in</em> <em>temperature</em> <em>âT</em></td>
<td width="53"><em>2.5</em></td>
<td width="53"><em>5.0</em></td>
<td width="59"><em>7.5</em></td>
<td width="53"><em>9.0</em></td>
<td width="53"><em>6.5</em></td>
<td width="54"><em>4.5</em></td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>b). i).</em></p>
<p><em>(2 marks)</em></p>
<p> ;</p>
<p><em>(1 mark)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="60"><em>ii).</em></td>
<td width="56"><em>Graph</em></td>
<td colspan="3" width="377"> ;</td>
<td width="126"><em> </em></p>
<p><em>(3 marks)</em></td>
</tr>
<tr>
<td width="60"><em>iii).</em></td>
<td width="56"><em>I</em></td>
<td colspan="3" width="377"><em>ât = 9.5 + 0.1<sup>0</sup>C</em></td>
<td width="126"><em>(1 mark)</em></td>
</tr>
<tr>
<td width="60"> ;</td>
<td width="56"><em>II</em></td>
<td colspan="3" width="377"><em>Maximum volume of A = 7.6cm<sup>3</sup> + 0.1</em></td>
<td width="126"> ;</td>
</tr>
<tr>
<td width="60"><em>iv).</em></td>
<td width="56"><em>I</em></td>
<td colspan="3" width="377"><em>Moles of sulphuric acid = <u>7.6 x 0.868</u></em></p>
<p><em>1000</em></td>
<td width="126"> ;</td>
</tr>
<tr>
<td colspan="2" width="116"><em> </em></p>
<p><em>II</em></td>
<td width="116"><em> </em></p>
<p><em>Heat evolved</em></td>
<td width="47"><em> </em></p>
<p><em>=</em></td>
<td width="215"><em>= 0.0066 moles</em></p>
<p><em>16 x 4.2 x 9.5</em></td>
<td width="126"><em>(1 mark)</em></td>
</tr>
<tr>
<td colspan="2" width="116"> ;</td>
<td width="116"><em> </em></p>
<p><em>Molar Heat</em></td>
<td width="47"><em>=</em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>=</em></td>
<td width="215"><em>638.4</em> <em>joules</em></p>
<p><em>= 638.4</em></p>
<p><em>0.0066</em></p>
<p><em>96.727272KJ mol<sup>-1</sup></em></td>
<td width="126"><em> </em></p>
<p><em> </em></p>
<p><em>(2 marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td rowspan="4" width="84"> ;</td>
<td width="75"><strong><em>2</em></strong></td>
<td width="338"><strong><em>Observations</em></strong></td>
<td width="302"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="75"><em>(a)</em></td>
<td width="338"><em>Gas with pungent/irritating/choking smell</em></p>
<p><em>is produced which changes moist blue litmus paper turns red</em></p>
<p><em>Colourless liquid formed on cool part of </em><em>test tube</em></p>
<p><em>Solid turns reddish brown</em></td>
<td width="302"><em>hydrated salt</em></p>
<p><em>acidic gas evolved</em></td>
</tr>
<tr>
<td width="75"><em>(b) (i</em></p>
<p><em>(ii)</em></td>
<td width="338"><em>Reddish</em> <em>brown</em> <em>solution</em> <em>pH</em> <em>1,</em> <em>2,</em> <em>3</em></p>
<p><em>Brown precipitate insoluble in excess Brown /Black solid formed or solution</em></td>
<td width="302"><em>strongly acidic</em> <em>Fe</em><em>3+</em></td>
</tr>
<tr>
<td width="75"> ;</td>
<td width="338"> ;</td>
<td width="302"> ;</td>
</tr>
<tr>
<td width="84"><em>97</em></td>
<td colspan="3" width="714"><em>Chemistry Practical Study Pack 1989 &#8211; 2016</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="75"><em>(iii)</em></p>
<p><em>(iv)</em></td>
<td width="338"><em>Changes</em> <em>from yellow to brown</em></p>
<p><em>White precipitate settles at the bottom of </em><em>the test tube</em></td>
<td width="302"><em>Iodide</em> <em>ions/</em> <em>I<sup>&#8211;</sup></em> <em>ions</em> <em>present</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="45"><strong><em>3</em></strong></td>
<td width="285"><strong><em>Observations</em></strong></td>
<td width="384"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="45"><em>(a)</em></td>
<td width="285"><em>Clear blue flame</em></td>
<td width="384"><em>saturated low carbon organic compound</em></p>
<p><em>( 2marks)</em></td>
</tr>
<tr>
<td width="45"><em>(b)</em></td>
<td width="285"><em>No separation or forms a solution</em></p>
<p><em>two liquids are miscible</em></td>
<td width="384"><em>Mixture is miscible or polar</em></p>
<p><em>organic compound (1 mark)</em></td>
</tr>
<tr>
<td width="45"><em>(c)</em></td>
<td width="285"><em>No effervescence</em></td>
<td width="384"><em>Liquid not acidic or absence of H<sup>+</sup> (2 marks)</em></td>
</tr>
<tr>
<td width="45"><em>(d)</em></td>
<td width="285"><em>Solution changes from orange to</em></p>
<p><em>green</em></td>
<td width="384"><em>F is likely to be</em></p>
<p><em>Alcohol or R-OH (2 marks)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong><em>NOVEMBER 2008 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><strong><em>PROCEDURE</em></strong></li>
</ol>
<p><strong> </strong></p>
<p><strong><em>TABLE 1 (4 Marks)</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Award a total of 4 marks distributed as follows</em></strong></p>
<p><strong> </strong></p>
<ul>
<li><em>Complete table </em><em>(1mark)</em></li>
<li><em>Table</em> <em>with</em> <em>10</em> <em>readings (1mark)</em></li>
</ul>
<p> ;</p>
<ul>
<li><strong><em><u>Penalties</u></em></strong>
<ul>
<li><em>Penalize ½ km once for any space not filled subject to at least 5 readings being given otherwise penalize fully</em></li>
<li><em>Penalize ½ mark for unrealistic temperature reading (i.e. from t=o min to t =2m if reading </em><em>of T40<sup>0</sup>C or T>; 40<sup>O</sup>C ) for the whole table </em></li>
<li><em>If temperature reading are all constant from t=o to t=5 min penalize ½ mark on complete </em><em>table</em></li>
<li><em>Penalise ½ mark on complete table if temperature reading at t=30min is either the same on greater higher than the temperature reading at t=2 min</em></li>
<li><em>I</em><em>f</em> <em>2</em> <em>o</em><em>r</em> <em>m</em><em>o</em><em>r</em><em>e</em> <em>r</em><em>o</em><em>w</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>e</em><em>m</em><em>pe</em><em>r</em><em>a</em><em>t</em><em>u</em><em>r</em><em>e</em> <em>r</em><em>e</em><em>a</em><em>d</em><em>i</em><em>n</em><em>g</em> <em>a</em><em>r</em><em>e</em> <em>g</em><em>i</em><em>ve</em><em>n</em><em>,</em> <em>penali</em><em>z</em><em>e</em> <em>½</em> <em>m</em><em>a</em><em>r</em><em>k on complete table and mark table based on the row used to plot the graph. However, if the graph is not drawn then mark the first row of </em></li>
</ul>
</li>
</ul>
<p> ;</p>
<ul>
<li><strong><em><u>Use of decimals</u></em></strong> <em>(1 mark)</em></li>
<li><em>accept temperature readings and award 1 mark If consistency given either </em><em>aswhole numbers a to 1 decimal place otherwise penalize fully</em></li>
<li><em>Reflect and ward 0 mark if decimal place has other values other than a ‘0’ or ‘5’ g. 20.2, </em><em>18.9</em></li>
</ul>
<p> ;</p>
<ul>
<li><strong><em><u>Accuracy</u></em></strong></li>
</ul>
<p><em>Compare the S.V. to the candidates temperature reading at 2 min and award 1 mark if the reading </em><em>is within +2.0<sup>0</sup>C of the S.V. otherwise award zero mark</em></p>
<p><strong><em><u>Note</u></em></strong></p>
<p><em>S</em><em>.</em><em>V</em> <em>r</em><em>e</em><em>f</em><em>e</em><em>r</em><em>s</em> <em>t</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>t</em><em>e</em><em>a</em><em>c</em><em>he</em><em>r</em><em>’</em><em>s</em> <em>t</em><em>e</em><em>m</em><em>pe</em><em>r</em><em>a</em><em>t</em><em>u</em><em>r</em><em>e</em> <em>r</em><em>e</em><em>a</em><em>d</em><em>i</em><em>n</em><em>g</em><em>s</em> <em>a</em><em>t</em> <em>t</em> <em>=</em> <em>0</em> <em>m</em><em>i</em><em>n</em> <em>whe</em><em>r</em><em>e</em> <em>a</em><em>l</em><em>l</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>v</em><em>e</em> <em>i</em><em>n</em><em>i</em><em>t</em><em>i</em><em>a</em><em>l</em> <em>t</em><em>e</em><em>m</em><em>pe</em><em>r</em><em>a</em><em>t</em><em>u</em><em>r</em><em>e </em><em>reading</em> <em>are</em> <em>the</em> <em>same</em> <em>or</em> <em>the</em> <em>temperature</em> <em>reading</em> <em>at</em> <em>t=2</em> <em>minutes</em> <em>in</em> <em>case the 5 initial temperature readings are not the same</em></p>
<p> ;</p>
<ul>
<li><strong><em><u>Trends</u></em></strong><strong><em> (1 mark)</em></strong></li>
</ul>
<table>
<tbody>
<tr>
<td width="74"></td>
</tr>
<tr>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Award two halves as follows</em></p>
<ul>
<li><em>If temperature reading from 0 to 2 min are constant award ½ mark or at least from E-1</em></li>
<li><em>Award ½ mark if temperature readings from t=3 min to t=5 min shows a rise after the initial drop without another drop</em></li>
</ul>
<p> ;</p>
<p><strong><em><u>Note</u></em></strong></p>
<ul>
<li><em>The reaction is endothermic a hence temperature must drop if not penalize ½ (in 3 minutes) on trend. i.e. to award the 2<sup>nd</sup> ½ mark for the trend there must have been a drop in temperature after 2 ½ minutes</em></li>
<li><em>Reject trend in the 2<sup>nd</sup> part of the table the addition of solid A to the acid otherwise accept </em><em>a minimum of two readings if they are lower and show a rise</em></li>
</ul>
<p><em>&#8211; Show the tick accuracy on the table</em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>GRAPH</em></strong></p>
<p><em>Award a total of 3 marks distributed as follows</em></p>
<ul>
<li><em>Labeling of axes ……………………………… </em><em>½ mark</em></li>
</ul>
<p><em>award ½ mark only if both axes are correct labeled (i.e. temperature on vertical and time </em><em>on horizontal )</em></p>
<p> ;</p>
<p><strong><em><u>Penalties</u></em></strong></p>
<ul>
<li><em>Penalise fully for inverted axes</em></li>
<li><em>Penalise fully if wrong units are used otherwise ignore if units are omitted</em></li>
</ul>
<p><em>/not</em> <em>used</em></p>
<ul>
<li><em>Penalise fully if one axis is correctly labeled</em></li>
</ul>
<p> ;</p>
<ul>
<li><strong><em>Scale</em></strong><strong><em>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230; </em></strong><strong><em>½ mark</em></strong></li>
</ul>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Area covered by plots should be at least half the provided on both axes e. at least 5 big squares on vertical and 4 ½ big squares on horizontal</em></li>
<li><em>Scale intervals must be consistent</em></li>
<li><em>Scale chosen must be able to accommodate all points or plots whether plotted or not check range of readings on the </em></li>
</ul>
<p> ;</p>
<p><strong><em><u>Note</u></em></strong></p>
<p><em>Penalise fully if any of the above conditions are not met</em></p>
<p> ;</p>
<p> ;</p>
<ul>
<li><strong><em>Plotting</em></strong><strong><em>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230; </em></strong><strong><em>1 mark</em></strong></li>
</ul>
<p><em>i). If 10 or 9 points are correctly plotted award 1 mark ii). If 8 or 7 points correctly plotted award ½</em></p>
<p><em>iii). If less than 7 points are correctly plotted award 0 marks</em></p>
<p> ;</p>
<ol start="2">
<li><em>If scale interval changes mark plots (if any ) within the first scale interval and treat to rest of the plots even if the axes are inverted or interchanged and award accordingly</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<ul>
<li><strong><em>The lines and extrapolation</em></strong><strong><em>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.. </em></strong><strong><em>(1 mark)</em></strong>
<ul>
<li><em>A</em><em>wa</em><em>r</em><em>d</em> <em>½</em> <em>m</em><em>a</em><em>r</em><em>k if the plots are joined by two straight lines, accept the lines of best fit</em></li>
<li><em>Award another ½ marks if for extrapolation where each of the two lines is extended to the </em><em>2 ½ minutes mark</em></li>
<li><em>Accept lines and extrapolation even if the axes are inverted</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>99</em></p>
<p> ;</p>
<p><em>Temperature </em><em>(<sup>O</sup>C)</em></p>
<p><em>Chemistry Practical Study Pack</em></p>
<p><strong><em>âT</em></strong></p>
<p><em>1989 &#8211; 2016</em></p>
<p> ;</p>
<p> ;</p>
<p><em>Temp (<sup>O</sup>C)</em></p>
<p><strong><em>Temperatur </em></strong><strong><em>e ( C)</em></strong></p>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p> ;</p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><em>Temp (<sup>O</sup>C)</em></p>
<p><em>Temp (<sup>O</sup>C)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Time</em> <em>(minutes)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Temperature </em><em>(<sup>O</sup>C)</em></p>
<p><em>Temp (<sup>O</sup>C)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Time</em> <em>(minutes)</em></p>
<p><em>Time (minutes)</em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Table 1</em></strong></p>
<table>
<tbody>
<tr>
<td width="77"><em>Time</em></p>
<p><em>(min)</em></td>
<td width="50"><em>0</em></td>
<td width="62"><em>½</em></td>
<td width="62"><em>1</em></td>
<td width="62"><em>1 ½</em></td>
<td width="62"><em>2</em></td>
<td width="57"><em>2 ½</em></td>
<td width="62"><em>3</em></td>
<td width="62"><em>3 ½</em></td>
<td width="62"><em>4</em></td>
<td width="62"><em>4 ½</em></td>
<td width="62"><em>5</em></td>
</tr>
<tr>
<td width="77"><em>Temp</em></p>
<p><em>(<sup>0</sup>C)</em></td>
<td width="50"><em>18.</em></p>
<p><em>0</em></td>
<td width="62"><em>18.0</em></td>
<td width="62"><em>18.0</em></td>
<td width="62"><em>18.0</em></td>
<td width="62"><em>18.0</em></td>
<td width="57"><em>X</em></td>
<td width="62"><em>13.0</em></td>
<td width="62"><em>13.0</em></td>
<td width="62"><em>13.5</em></td>
<td width="62"><em>13.5</em></td>
<td width="62"><em>14.0</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ul>
<li><em>âT = Correct reading 6<sup>0</sup>C 1 mark</em></li>
</ul>
<p> ;</p>
<p><strong><em><u>Conditions</u></em></strong></p>
<ul>
<li><em>Accept the correct value of âT from an extrapolated correct graph with or without showing on the graph for 1 mark</em></li>
<li><em>award ½ mark for correct showing on an extrapolated correct graph if reading for âT is wrong or missing</em></li>
<li><em>Ignore sign for âT</em></li>
<li><em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>wrong</em> <em>units</em> <em>used</em> <em>otherwise</em> <em>ignore</em> <em>if no units are used/shown</em></li>
<li><em>Reject readings/showing from a wrong graph and award 0 mark for âT reject âT if coming from the table or wrong graph but accept in (iii) below if used correctly</em></li>
<li><em>Reject âT if from the table or wrong graph but accept if it is used correctly otherwise penalize fully if âT is strange</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>âH = MCâT √(expression)</em></li>
</ul>
<p><em>= 20 x 4.2 x Answer (ii) above(6)</em></p>
<p><em>= 504 joules</em></p>
<p> ;</p>
<p><strong><em>Or</em></strong></p>
<p><em>âH = MCâT</em></p>
<p><em>= <u>20 x 4.2 x Answers (ii) above</u></em></p>
<p><em>1000</em></p>
<p><em>= Correct Answer</em></p>
<p> ;</p>
<p><strong><em>Table 2</em></strong></p>
<table>
<tbody>
<tr>
<td width="240"> ;</td>
<td width="165"><strong><em>I</em></strong></td>
<td width="165"><strong><em>II</em></strong></td>
<td width="144"><strong><em>III</em></strong></td>
</tr>
<tr>
<td width="240"><em>Final burette reading</em></td>
<td width="165"><em>16.50</em></td>
<td width="165"><em>32.20</em></td>
<td width="144"><em>32.20</em></td>
</tr>
<tr>
<td width="240"><em>Initial burette reading</em></td>
<td width="165"><em>0.00</em></td>
<td width="165"><em>16.00</em></td>
<td width="144"><em>16.00</em></td>
</tr>
<tr>
<td width="240"><em>Titre (cm<sup>3</sup>)</em></td>
<td width="165"><em>16.50</em></td>
<td width="165"><em>16.20</em></td>
<td width="144"><em>16.20</em></td>
</tr>
</tbody>
</table>
<p><strong><em>Award a total of 5 marks distributed as follows </em></strong><em>(i) Average Titre = <u>16. 20 + 16.20</u> = 16 .20cm<sup>3</sup></em></p>
<p><em>2</em></p>
<ul>
<li><em>The</em> <em>number</em> <em>of</em> <em>moles</em> <em>of:</em>
<ul>
<li><em>Moles of NaOH used = <u>1 x Titre</u></em></li>
</ul>
</li>
</ul>
<p><em>1000</em></p>
<p> ;</p>
<ul>
<li><em>Moles of NaOH: HCl = 1 :1</em></li>
</ul>
<p><em>Moles </em><em>of HCl = Ans I above Or Moles of HCl in 25cm<sup>3</sup> of soln = Ans I above.</em></p>
<p> ;</p>
<ul>
<li><em>Ans <u>II x 250</u> </em><em>= correct answer</em></li>
</ul>
<p><em>25</em></p>
<p><em>Or</em></p>
<p><em>Ans II x 10 = Correct Ans</em></p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<p><em>i). Penalise ½ mark for wrong transfer of answer (II) ii). Penalise fully for strange figure</em></p>
<p><em>iii</em><em>)</em><em>.</em><em> Answer as expected otherwise penalize ½ mark (don’t work at accuracy, d.p) for wrong answer</em></p>
<p> ;</p>
<p><strong><em>Notes</em></strong></p>
<ul>
<li><em>Award fully if correct answer given is based on statement implying </em><em>multiplication of ten</em></li>
</ul>
<p> ;</p>
<p><em>IV). <u>2 x 20</u></em></p>
<p> ;</p>
<p><em>1000 = 0.04</em></p>
<p><em>Answer</em> <em>as</em> <em>expected</em> <em>otherwise</em> <em>penalize ½ mark</em></p>
<ol>
<li><em>V) </em><em>Moles of HCl reacted with solid A = Ans IV – Ans III</em></li>
</ol>
<p><em>= Correct Ans</em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<p><em>Answer</em> <em>(IV)</em> <em>III</em> <em>must</em> <em>be</em> <em>transferred</em> <em>intact</em> <em>otherwise</em> <em>penalize ½ mark for wrong transfer of either of item or both. However for strange figures penalize fully.</em></p>
<p><strong><em>Note</em></strong></p>
<ol>
<li><em>If soluble or dissolve is not given but blue ppt mentioned accept and award 1 mark for blue solution</em></li>
<li><em>If ppt and dissolve are not mentioned but a candidate mentions deep blue </em><em>solution</em> <em>in excess credit ½ mark and reject the </em></li>
</ol>
<p> ;</p>
<ul>
<li><em>Ans (iii) Procedure A = Correct ans</em></li>
</ul>
<p><em>ANS v UNITS j Mol- OR Kj Mot Or</em></p>
<p><em>Ans v = Ans iii procedure A</em></p>
<p><em>: I Mole of HCl = <u>Ans (iii) Procedure A</u></em></p>
<p><em>Ans V</em></p>
<p><em>=<u>Correct Ans</u> JMol<sup>-1</sup></em></p>
<p><em>Or</em></p>
<p><em>Ans v = Ans (i) Procedure A (Joules)</em></p>
<p><em>; </em><em>1 Mole of HCl = <u>Ans (iii) Procedure A</u></em></p>
<p><em>Ans V x 1000</em></p>
<p><em>Jmol<sup>-1</sup> or KJ mol<sup>-1</sup></em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="54"><em>2</em></td>
<td width="353"><em>Observations</em></td>
<td width="332"><em>Inferences</em></td>
</tr>
<tr>
<td width="54"><em>a</em></td>
<td width="353"><em>Green solid turns black/ Green solid forms black solid/ residue ; Colourless liquid forms on the cooler part of the test tube/ Colourless vapour condenses on the cooler part of the test tube ; Blue litmus turns red; Red litmus remains red/ the same colour.</em></p>
<p><em>Penalise fully for contradiction on colour properties</em></p>
<p><em>Rej. Colourless liquid condenses / colourless vapour forms/moisture condenses/No effect on red litmus/Red litmus remains the same colour</em></td>
<td width="332"><em>&#8211; Hydrated salt/compound or contain water of crystallization (Tied to colourless vapour condensing) Acidic gas produced (Tied to blue litmus turning red.</em></td>
</tr>
<tr>
<td width="54"><em>b</em></td>
<td width="353"><em>Black solid / residue reacts dissolves to form green solution Or Green solution formed Ignore – No effervescence Rej. Blue</em></p>
<p><em>solution/ No change/ reaction</em></td>
<td width="332"><em>Black solid/ residue is basic/ Colored ion present / or Cu<sup>2+</sup>, Fe<sup>2</sup><sup>+</sup> ions present</em></td>
</tr>
<tr>
<td width="54"><em>c</em> <em>(i)</em></td>
<td width="353"><em>Blue ppt/ suspension /solid formed / Blue ppt dissolves in excess aqueous ammonia to</em></p>
<p><em>form a deep blue solution</em></td>
<td width="332"><em>Cu<sup>2+</sup> Present <sup>(</sup> tied to blue ppt and deep blue solution</em></p>
<p><em>Must</em></td>
</tr>
<tr>
<td width="54"><em>(ii)</em></td>
<td width="353"><em>Effervescence occurs / bubbles formed/ Fizzing; Rej hissing/ Brown/ reddish brown solid deposited/ Green solution turns colourless / Test tube becomes warm /hot</em></td>
<td width="332"><em>E is a metal above copper in the ECS / Metal E displaces copper/ metal E is more reactive than cooper / metal E reduced Cu<sup>2+</sup> ions to Cu ( Tied to brown solid</em></p>
<p><em>deposit)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="54"><em>3</em></td>
<td colspan="5" width="323"><em>Observations</em></td>
<td width="362"><em>Inferences</em></td>
</tr>
<tr>
<td width="54"><em>a</em></td>
<td colspan="5" width="323"><em>Burns with a yellow sooty smoky flame</em></p>
<p><em>½ mark</em></p>
<p><em>Burns with a luminous sooty/smoky flame</em></td>
<td width="362"><em>– long chain/ unsaturated organic/ hydrocarbon with a</em></p>
<p><em>high C: H ratio C = C or &#8211; C = C ½ marks</em></p>
<p><strong><em><u>Reject</u></em></strong></p>
<p><em>C</em> <em>=</em> <em>C</em><em>,</em> <em>C</em> <em>=</em> <em>C</em></p>
<p><em>Carbon to carbon double or triple bond in words</em></p>
<p><em>Alkaline /alkaline</em></td>
</tr>
<tr>
<td width="54"><em>b</em></td>
<td colspan="5" width="323"><em>Dissolves/ soluble to form a colourless solution</em></td>
<td width="362"><em>Polar organic compound Note Accept soluble</em></p>
<p><em>/substance/salt/compound present</em></td>
</tr>
<tr>
<td width="54"><em>c</em> <em>(i)</em></td>
<td width="106"><em>Effervesnce formed</em></td>
<td width="68"><em>occurs</em></td>
<td width="33"><em>or</em></td>
<td width="76"><em>bubbles</em></td>
<td width="41"><em>are</em></td>
<td width="362"><em>R – COOH / H<sup>+</sup>/ H</em><em>3</em><em>O<sup>+</sup></em></p>
<p><em>Accept &#8211; Acidic compound /solution</em></p>
<p><em>Organic</em> <em>compound ; Carboxylic acid</em></td>
</tr>
<tr>
<td width="54"><em>(ii)</em></td>
<td colspan="5" width="323"><em>Orange colour K</em><em>2</em><em>Cr</em><em>2</em><em>O</em><em>7 </em><em>solution persists</em></p>
<p><em>/ remain the same / orange / orange colour</em></p>
<p><em>Rej – Yellow used in place of orange</em></p>
<p><em>K</em><em>2</em><em>Cr</em><em>2</em><em>O</em><em>7 </em><em>not decolourised</em></td>
<td width="362"><em>R – OH absent</em></p>
<p><em>Note : Penalise fully if any other functional groups are mentioned</em></td>
</tr>
<tr>
<td width="54"><em>(iii)</em></td>
<td colspan="5" width="323"><em>Purple KMnO</em><em>4 </em><em>soln is decolorized or KMnO</em><em>4 </em><em>soln changes from purple to </em><em>colourless</em></p>
<p><em>Note : Rej Solution remains / becomes / </em><em>turns colourless</em></td>
<td width="362"><em> </em></p>
<p> ;</p>
<p><em>&#8211; C=C- / C = C &#8211; present</em></p>
<p><em>Accept for unsaturated organic compound present</em></td>
</tr>
<tr>
<td width="44"></td>
<td width="105"></td>
<td width="61"></td>
<td width="27"></td>
<td width="72"></td>
<td width="36"></td>
<td width="288"></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2009 MARK SCHEME</em></strong></p>
<p><strong> </strong></p>
<p><em>1.</em></p>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="90"><em>III</em></td>
<td width="9"> ;</td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"><em>22.20</em></td>
<td width="105"><em>21.50</em></td>
<td colspan="2" width="99"><em>22.50</em></td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"><em>0.00</em></td>
<td width="105"><em>0.00</em></td>
<td colspan="2" width="99"><em>1.00</em></td>
</tr>
<tr>
<td width="345"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="120"><em>22.20</em></td>
<td width="105"><em>21.50</em></td>
<td colspan="2" width="99"><em>21.50</em></td>
</tr>
</tbody>
</table>
<p><em>(4 marks)</em></p>
<ul>
<li><em>i). </em><em>Average volume of solution C used</em></li>
</ul>
<p><em>= <u>21.50 + 21.50</u></em></p>
<p><em>2</em></p>
<p><em>= 21.50 (1 mark)</em></p>
<ul>
<li><em>Moles of sodium hydroxide in the average volume of solution C </em></li>
</ul>
<p><em>100cm<sup>3</sup> of sodium contains 0.3 moles of NaOH 21.50cm<sup>3</sup> of solution contains 0.3 x 21.5</em></p>
<p><em>1000</em></p>
<p><em>= 0.00645 moles (1 mark) iii). Moles of hydrochloric acid in 25.0cm<sup>3</sup> of solution D</em></p>
<p><em>= 0.00645 moles (1 mark)</em></p>
<p><em>iv). Morality of hydrochloric acid in solution D.</em></p>
<p><em>25cm<sup>3</sup> of solution contains 0.00645 moles Hcl</em></p>
<p><em>0.00645 x 1000</em></p>
<p><em>100cm<sup>3</sup> of solution contains</em><em> </em><em>25</em></p>
<p> ;</p>
<p><em>= 0.25M (1mark)</em></p>
<table>
<tbody>
<tr>
<td width="541">
<table width="100%">
<tbody>
<tr>
<td>
<table>
<tbody>
<tr>
<td width="345"> ;</td>
<td width="120"><em>I</em></td>
<td width="105"><em>II</em></td>
<td width="90"><em>III</em></td>
<td width="9"> ;</td>
</tr>
<tr>
<td width="345"><em>Final burette reading</em></td>
<td width="120"><em>21.50</em></td>
<td width="105"><em>20.90</em></td>
<td colspan="2" width="99"><em>20.90</em></td>
</tr>
<tr>
<td width="345"><em>Initial burette reading</em></td>
<td width="120"><em>0.00</em></td>
<td width="105"><em>0.00</em></td>
<td colspan="2" width="99"><em>0.00</em></td>
</tr>
<tr>
<td width="345"><em>Volume of solution D used (cm<sup>3</sup>)</em></td>
<td width="120"><em>21.50</em></td>
<td width="105"><em>20.90</em></td>
<td colspan="2" width="99"><em>20.90</em></td>
</tr>
</tbody>
</table>
<p> ;</td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Table 2</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>i). Average volume of solution D used</em></li>
</ul>
<p><em><u>20.90 + 20.90</u></em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>(4 marks)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="2">
<li><em> a).</em></li>
</ol>
<p><em>2 = 20.90cm<sup>3</sup> (1 mark)</em></p>
<p> ;</p>
<p><em>ii). Moles of hydrochloric acid in average volume of solution D used 1000cm<sup>3</sup> of solution contains 0.258 moles of HCl</em></p>
<p><em>20.90cm<sup>3</sup> of solution contains <u>0.258 x 20.90</u> moles</em></p>
<p><em>1000</em></p>
<p><em>= 0.0054 moles (1 mark) iii). Moles of the metal carbonate, solid A in 25.0cm<sup>3</sup> of solution A.</em></p>
<p><em>Mole ratio of acid to carbonate 2: 1 </em><em>(1 mark)</em></p>
<p><em>½ x 0.0054</em></p>
<p><em>= 0.0027 moles (1 mark)</em></p>
<p><em>iv). The solubility of the metal carbonate in g/100g of solution mass of carbonate = 0.0027 x 74</em></p>
<p><em>in 25.0cm<sup>3</sup> of solution = 0.1998g</em></p>
<p><em>100g of solution will contain </em><em><u>0.1998 x 100g</u></em> <em>of carbonate</em></p>
<p><em>25</em></p>
<p><em>= 0.7992g/100g of solution (1 mark)</em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Observations Inferences</em></strong></p>
<p><em>Colourless liquid </em><em>hydrated</em> <em>salt/</em> <em>compound</em> <em>or</em> <em>contains</em> <em>Condenses on the cooler parts of test tube water of crystallization (Tied to</em></p>
<p><em>Gas produced forms white Colourless liquid forming after fumes with fumes HCl. (2 marks) Or condensation</em></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>solid</em> <em>sublimes/forms</em> <em>a white sublimate Ammonia gas (NH <sup>+</sup> ) present ( tied to white solid formed on the cooler parts gas forming with HCl</em></p>
<p><em>of the test tube</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>b).</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>for</em> <em>each</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Pb<sup>2+</sup> in</em></p>
<p><em>ii).</em></p>
<p><strong><em>Observations Inferences</em></strong></p>
<p><em>No white ppt / No white solid </em><em>Pb<sup>2+</sup> absent</em></p>
<p><em>No white suspension No effervescence/ No bubbles</em></p>
<p><em>or Al<sup>3+</sup> present tied to white ppt Note: if a candidate mentions</em></p>
<p> ;</p>
<p><em>Rej. No observable change Place of Al<sup>3+</sup> present credit ½</em></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>No ppt / change/reaction </em><em>CO <sup>2-</sup> and SO</em><em>3 </em><em>absent Tied to no</em></p>
<p><em>No white substance Effervescence. (2 marks)</em></p>
<p><em>Colourless soln formed NB. To award ‘Al<sup>3+</sup> present it must have</em></p>
<p><em>Soln remains colourless been credited in b (i) ; To award</em></p>
<p><em>No colour change Pb<sup>2+</sup> absent it must have been mentioned as present in b (i); Ignore mention of Ag<sup>+</sup> absent</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>iii).</em></p>
<p> ;</p>
<p><strong><em>Observations</em></strong></p>
<p><em>White ppt /solid/suspension</em></p>
<p> ;</p>
<p><strong><em>Inferences</em></strong></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>&#8211;</em> <em>SO</em> <em><sup>2-</sup></em> <em>present</em></p>
<p> ;</p>
<p> ;</p>
<p><em>without</em></p>
<p><em>which does not dissolve on boiling &#8211; If a candidate mentions Cl<sup>&#8211;</sup></em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>giving SO <sup>2-</sup> present award ½ mark</em></p>
<p><em>Penalise fully for any contradictory ion</em></p>
<p> ;</p>
<p><em>(1 mark)</em></p>
<p><em>Formulae of the ion must be given correctly in all the above inferences. Rej ions given in words only (2 marks)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><em>a). <strong>Observations Inferences</strong></em></li>
</ol>
<p><em>White solid dissolves to F is a non polar compound</em></p>
<p><em>form a colourless solution (1 mark) (1 mark)</em></p>
<p><em>Accept a colorless solution formed Without mention of dissolve or soluble For 1 mark</em></p>
<p><em>Forms a solution / clear solution without </em><em>Mention of dissolve or soluble for 1 mk</em></p>
<p> ;</p>
<ol>
<li><strong><em>Observations Inferences</em></strong></li>
</ol>
<p><em>P<sup>H</sup> = 7 Neutral solution</em></p>
<p><em>(1 mark) (1 mark)</em></p>
<p><em>Note: Ignore mention of colour Accpt: Soln neither acidic nor alkaline of mixture; Reject pH range </em><em>Rej</em> <em>basic used in place of alkaline</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>ii).</em></p>
<p> ;</p>
<p><strong><em>Observations</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Inferences</em></strong></p>
<p> ;</p>
<p><em>No effervescence/ No bubbles (1 mark)</em></p>
<p><em>H<sup>+</sup> absent</em></p>
<p><em>Accept</em> <em>soln not acidic for ½ mk in the absence of H<sup>+</sup> absent</em></p>
<p><em>Ignore R – COOH absent</em></p>
<p> ;</p>
<p><em>b).</em></p>
<ul>
<li><strong><em>Observations </em></strong><em>Effervescence giving off a Colourless solution formed</em></li>
</ul>
<p><em>Accept Fizzing used in place of Effervescence or bubbles for</em></p>
<p><em>(1 mark)</em></p>
<p> ;</p>
<ol>
<li><strong><em>Observations</em></strong></li>
</ol>
<p><em>Does not turn green. Orange </em><em>Color of K</em><em>2 </em><em>Cr</em><em>2 </em><em>O</em><em>7 </em><em>(1 mark) </em><em>Note both initial colour and </em><em>Final colour must be given Otherwise penalize fully Accpt: Orange colour of K</em><em>2</em><em>Cr</em><em>2</em><em>O</em><em>7 </em><em>solution persists / </em><em>r</em><em>e</em><em>m</em><em>a</em><em>i</em><em>n</em><em>s</em><em>;</em></p>
<p><em>Rej: Yellow used in place of </em><em>orange</em></p>
<p><strong><em>Inferences</em></strong></p>
<p><em>Carboxylic/alkanoic acid preset </em><em>Or – COOH present/ H<sup>+</sup>/ H</em><em>3</em><em>O<sup>+</sup></em></p>
<p><em>(1 mark) <strong>Inferences</strong></em></p>
<p><em>Alcohol absent / R &#8211; OH Rej – OH (2 marks)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>iii).</em></p>
<p><strong><em>Observations Inferences</em></strong></p>
<p> ;</p>
<p><em>Bromine water not decolourised Accept yellow/ Orange / red colour of bromine water</em> <em>persists</em></p>
<p> ;</p>
<p><em>/</em> <em>remains </em><em>(1</em> <em>mark)</em></p>
<p><em>C = C / &#8211; C = C &#8211; absent</em></p>
<p><em>Accept unsaturated organic compound absent for ½ mk. Penalise fully for any contradictory / functional groups</em></p>
<p><em>(1 mark)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2010 MARKSCHEME</em></strong></p>
<p><strong> </strong></p>
<p><em>Q1. Table 1………………………. 5 marks</em></p>
<p><em>a). Complete table …………………. 1 mark</em></p>
<p> ;</p>
<p><strong><em><u>NOTE;</u></em></strong> <em>i). </em><em>In case there was wrong arithmetic /substration in the table, use the correct values in averaging for the final answer.</em></p>
<ul>
<li><em>Where there are two possible average titles use the value which gives the candidates maximum </em></li>
<li><em>I</em><em>f</em><em> wrong values are averaged, pick the correct values (if any) following the principles of averaging, average and award accordingly.</em></li>
</ul>
<p><em>e.g. 1 S.V = 15.80cm<sup>3</sup></em></p>
<p><em>C</em><em>o</em><em>nd</em><em>i</em><em>t</em><em>i</em><em>o</em><em>n</em><em>s</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em><em>s</em> <em>a</em><em>r</em><em>e</em> <em>15</em><em>.</em><em>4</em><em>c</em><em>m</em><em><sup>3</sup></em><em>,</em> <em>15</em><em>,</em><em>6</em><em>c</em><em>m</em><em><sup>3</sup></em><em>,</em> <em>15</em><em>.</em><em>8</em><em>c</em><em>m</em><em><sup>3</sup></em></p>
<p> ;</p>
<p><em>Candidates working</em></p>
<p><em>Either <u>15.4 + 15.6 + 15.8</u></em></p>
<p><em>3</em></p>
<p><em>= 15.60cm<sup>3</sup> (1 mark)</em></p>
<p><em>OR <u>15.4 + 15.6</u></em></p>
<p><em>2</em></p>
<p><em>= 15.5cm<sup>3</sup> (1 mark)</em></p>
<p><em>Examiner to pick </em><em>= <u>15.6 + 15.8</u> = 15.7cm<sup>3</sup></em></p>
<p><em>2 (1 mark)</em></p>
<p> ;</p>
<p><em>2 S.V </em><em>= 15.50cm<sup>3</sup></em></p>
<p><em>Candidates values are 15.8, 15.6, 15.6 </em><em>Candidates working</em></p>
<p> ;</p>
<p> ;</p>
<p><em>3 S.V = 15.90cm<sup>3</sup></em></p>
<p><em><u>15.6 + 15.6</u></em></p>
<p><em>2 = 15.6cm<sup>3</sup> ½ mark</em></p>
<p> ;</p>
<p> ;</p>
<p><em>C</em><em>a</em><em>nd</em><em>i</em><em>d</em><em>a</em><em>t</em><em>e</em><em>’</em><em>s</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em><em>s</em> <em>a</em><em>r</em><em>e</em> <em>16</em><em>.</em><em>0</em><em>,</em> <em>15</em><em>.</em><em>8</em><em>,</em> <em>a</em><em>n</em><em>d</em> <em>15</em><em>.</em><em>6 </em><em>Candidates working</em></p>
<p><em><u>15.8 + 15.6</u></em></p>
<p><em>2 </em><em>= 15.70cm<sup>3</sup></em></p>
<p><em>And</em> <em>award</em> <em>1</em> <em>mark</em> <em>instead</em> <em>of</em> <em>½</em> <em>mark</em> <em>if</em> <em>the</em> <em>candidates</em> <em>value</em> <em>are used</em></p>
<p> ;</p>
<p><em>CT</em> <em>–</em> <em>1;</em> <em>D </em><em>&#8211; 1; A – 1; PA – 1; FA <u>&#8211; 1</u></em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>CALCULATIONS</em></strong></p>
<p><em>i). No. of moles of NaOH in 25cm<sup>3</sup> of solution B = <u>2 x 25</u></em></p>
<p><em>1000</em></p>
<p><em>Moles of NaOH in 250cm<sup>3</sup> of solution D = <u>2 x 25</u></em></p>
<p><em>1000</em></p>
<p><em>Hence Conc. of solution D = <u>2 x 25</u> x <u>1000</u></em></p>
<p><em>1000 250</em></p>
<p><em>= 0.200 mols</em></p>
<p><em>Or</em></p>
<p><em>Conc of solution D = <u>2 x 25 </u>x <u>1000</u></em></p>
<p><em>1000 250</em></p>
<p><em>= 0.200 mol L</em></p>
<p><em>Or</em></p>
<p><em>M</em><em>c </em><em>V</em><em>c </em><em>= M</em><em>d </em><em>V</em><em>d </em><em>= M</em><em>1 </em><em>V</em><em>1 </em><em>= M</em><em>2 </em><em>V</em><em>2 </em><em>/M</em><em>g </em><em>V</em><em>g </em><em>= M</em><em>d </em><em>V</em><em>d </em><em>Md (Or M</em><em>2</em><em>) or md = <u>2 x 25</u></em></p>
<p><em>100</em></p>
<p><em>Or</em></p>
<p><em>Conc of solution D = <u>2 x 1</u></em></p>
<p><em>10</em></p>
<p><em>= 0.200 mol-1</em></p>
<p> ;</p>
<ul>
<li><em>Moles of NaOH in 25cm<sup>3</sup> of solution D used</em></li>
</ul>
<p><em>=</em> <em><u>Ans</u></em> <em><u>(II)</u></em> <em><u>x</u></em> <em><u>25</u></em></p>
<p><em>1000</em></p>
<p> ;</p>
<p><em>Moles of alkanoic acid used = <sup>1</sup>/</em><em>3 </em><em>x ans (II) x<u> 25</u></em></p>
<p><em>1000</em></p>
<p><em>Hence conc of solution C = <sup>1</sup>/</em><em>3 </em><em>x <u>ans (II</u>) x 25 x <u>1000</u></em></p>
<p><em>1000 Titre</em></p>
<p><em>= correct ans.</em></p>
<p><em>OR</em></p>
<p><em>Conc of solution C = <sup>1</sup>/</em><em>3 </em><em>x <u>ans (II) x 25</u></em></p>
<p><em>Titre</em></p>
<p><em>=</em> <em>Correct</em> <em>ans.</em></p>
<p><em>OR</em></p>
<p><em>Ma V</em><em>a </em><em>= <sup>1</sup>/</em><em>3 </em><em>= Ma = <sup>1</sup>/</em><em>3 </em><em>x <u>ans (II) x 25</u> M</em><em>b</em><em>V</em><em>b </em><em>Titre</em></p>
<p><em>= correct answer</em></p>
<ul>
<li><em>Molar mass of the alkanoic acid</em></li>
</ul>
<p> ;</p>
<p><em>= 25.0</em></p>
<p><em>Ans (III)</em></p>
<p><em>= Correct answer</em></p>
<p> ;</p>
<p><em>Note: i). Penalise ½ mark for wrong transfer of ans (III) otherwise penalize fully for strange figures used.</em></p>
<ul>
<li><em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>wrong</em> <em>answer</em> <em>if</em> <em>arithmetic</em> <em>error</em> <em>is</em> <em>outside</em> <em>+5</em> <em>units</em> <em>in the 1<sup>st</sup> p</em></li>
<li><em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>either</em> <em>omission</em> <em>of</em> <em>the</em> <em>(g)</em> <em>units</em> <em>or</em> <em>for</em> <em>wrong</em> <em>units used</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p><strong><em>Procedure</em></strong></p>
<p><strong> </strong></p>
<p><strong> </strong></p>
<p><em>GRAPH</em></p>
<p><em>Table</em> <em>II</em><em>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.. </em><em>6 marks</em></p>
<p> ;</p>
<ul>
<li><em>Labelling of axes ………………………………………. </em><em>½ mark to award the ½ mark both axes must by correctly labelled</em></li>
</ul>
<p> ;</p>
<p><em><u>Conditions</u></em></p>
<ul>
<li><em>Penalise fully for wrong units used otherwise accept correct labeling even if no units are shown</em></li>
<li><em>Penalise fully if only one axis is correctly labelled</em></li>
<li><em>Change in temperature (âT) must appear on the vertical axis and volume of solution A on horizontal axis, otherwise penalize fully for inverted Axes</em></li>
<li><em>Reject labeling of axes if temperature alone is used instead of change in temperature (âT) in vertical </em></li>
</ul>
<p> ;</p>
<p><em>b). Scale …………………………………………………… ½ mark</em></p>
<ul>
<li><em>Area</em> <em>covered</em> <em>by</em> <em>the</em> <em>actual</em> <em>plots</em> <em>must</em> <em>be</em> <em>at</em> <em>least</em> <em>3</em> <em>½</em> <em>big</em> <em>square</em> <em>(vertical</em> <em>axis)</em> <em>by 4 ½ big square (horizontal axis)</em></li>
<li><em>The scale internal must be constant on each axis</em></li>
<li><em>S</em><em>c</em><em>a</em><em>l</em><em>e</em> <em>c</em><em>h</em><em>o</em><em>s</em><em>e</em><em>n</em> <em>m</em><em>u</em><em>s</em><em>t</em> <em>b</em><em>e</em> <em>a</em><em>bl</em><em>e</em> <em>t</em><em>o</em> <em>a</em><em>cc</em><em>o</em><em>mm</em><em>o</em><em>d</em><em>a</em><em>t</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>plo</em><em>t</em><em>s</em><em>,</em> <em>whe</em><em>t</em><em>he</em><em>r</em> <em>plo</em><em>tt</em><em>e</em><em>d</em> <em>o</em><em>r</em> <em>n</em><em>o</em><em>t </em><em>(chalk the range of values on both axes)</em></li>
</ul>
<p><em>NB: i). Penalise fully if any of the above conditions is not met</em></p>
<p><em>ii). Award for the scale even if the axes are in interchanged so long as the above conditions are met</em></p>
<p> ;</p>
<p><em>c). Plotting ……………………………………………….. ½ mark i). For 5 or 6 points plotted correctly award 1 mark</em></p>
<p><em>ii). If 4 or 3 points are correctly plotted award ½ mark iii). For less than 3 points correctly plotted award 1 mark</em></p>
<ul>
<li><em>I</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>c</em><em>a</em><em>l</em><em>e</em> <em>i</em><em>n</em><em>t</em><em>e</em><em>r</em><em>v</em><em>a</em><em>l</em> <em>c</em><em>h</em><em>a</em><em>n</em><em>g</em><em>e</em><em>s</em><em>,</em> <em>m</em><em>a</em><em>ke the plots (if any) in the first scale interval only.</em></li>
</ul>
<p><em>Consider</em> <em>the</em> <em>rest</em> <em>of</em> <em>the</em> <em>plots</em> <em>(If</em> <em>any)</em> <em>as</em> <em>wrong plots</em></p>
<ul>
<li><em>Accept the correct plots even if the axis are inverted /interchanged</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>The line/shape…………………………………….. </em><em>1 mark</em> <strong><em>Conditions</em></strong>
<ul>
<li><em>Award ½ mark for straight line showing a risk</em></li>
<li><em>Award another ½ mark for an extrapolated line showing a drop </em><em>NB: Accept lines of best fit</em></li>
<li><em>I</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>a</em><em>x</em><em>e</em><em>s</em><em>,</em> <em>a</em><em>r</em><em>e</em> <em>i</em><em>n</em><em>t</em><em>e</em><em>r</em><em>c</em><em>h</em><em>a</em><em>n</em><em>g</em><em>e</em><em>d</em> <em>/</em><em>i</em><em>n</em><em>ve</em><em>r</em><em>t</em><em>e</em><em>d</em> <em>r</em><em>e</em><em>j</em><em>e</em><em>c</em><em>t</em> <em>t</em><em>h</em><em>e</em> <em>l</em><em>i</em><em>n</em><em>e</em><em>s</em> <em>a</em><em>n</em><em>d</em> <em>t</em><em>h</em><em>e</em> <em>r</em><em>e</em><em>a</em><em>d</em><em>i</em><em>n</em><em>g</em><em>s</em> <em>f</em><em>r</em><em>o</em><em>m</em> <em>t</em><em>h</em><em>e </em><em>graph in (b) but accept the reading in subsequent workings in (c) and (d)</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p> ;</p>
<p><em>108 Chemistry Practical Study Pack 1989 &#8211; 2016</em></p>
<p><em>Award 1 mark</em></p>
<p> ;</p>
<p><em>âT</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>Accept any one of the following for ½ mark</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p>âT âT</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Volume of solution A (cm<sup>3</sup>) Volume of solution A (cm<sup>3</sup>)</em></p>
<p> ;</p>
<p>Award 1 mark</p>
<p> ;</p>
<p>âT âT</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Volume of solution A (cm<sup>3</sup>) b). Volume of solution A= Vcm</em></p>
<p><em><u>NB:</u></em></p>
<p><em>Volume of solution A (cm<sup>3</sup>)</em></p>
<p> ;</p>
<ul>
<li><em>Accept correct reading of V with or within showing on extrapolated graph for</em></li>
</ul>
<p> ;</p>
<p><em>1 mark</em></p>
<ul>
<li><em>If shown on the graph correctly but reading is wrong or not given award only ½ mark for correct showing on the graph</em></li>
<li><em>Penalise ½ mark for wrong units otherwise ignore if units not given </em><em>iv). If value of V >; 25cm<sup>3</sup> reject and award</em></li>
</ul>
<p><em>vi). Reject showing and reading of V from a wrong graph but accept in (c) below if need correct</em></p>
<p> ;</p>
<ul>
<li><em>Volume of B = 30 – Ans (b) above (30 –v)</em></li>
</ul>
<p><em>correct</em> <em>ans.</em></p>
<p> ;</p>
<p><em><u>NB;</u></em><em> i). V of 30cm<sup>3</sup> is unrealistic and unacceptable and hence penalize fully and consequently. Reject working in both d (i) and d (ii) below and award o mark in each case</em></p>
<p> ;</p>
<p><em>ii). Penalise ½ mark for wrong units and another ½ mark if working not shown</em></p>
<ul>
<li><em>i). Ratio of volume A and B</em></li>
</ul>
<p><em>= Ans (b); Ans (c) Or</em></p>
<p><em>Ans (c); Ans (b)</em></p>
<p><em>= 1: 1</em></p>
<p> ;</p>
<p><em>NB: If ratio is not 1: 1 penalise ½ mark but accept the ratio in d (ii) if used correctly</em></p>
<p><em>Moles of acid used = Moles of NaOH Molarity of acid = <u>2 x Ans (c )</u> x <u>1000</u></em></p>
<p><em>1000 Ans (b)</em></p>
<p><em>= corr. Ans</em></p>
<p><em>OR</em></p>
<p><em>Conc of solution A = <u>2 x Ans (c)</u></em></p>
<p><em>Ans b</em></p>
<p><em>= Correct Ans</em></p>
<p><em>OR</em></p>
<p><em>M</em><em>A</em> <em>V</em><em>A </em><em>= <u>M</u></em><em><u>B </u></em><em><u>V</u></em><em><u>B</u></em></p>
<p><em>M</em><em>A </em><em>= 2 x Ans</em></p>
<p><em>Ans(b)</em></p>
<p><em>= Corr. Ans</em></p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Accept answer tied correct arithmetic otherwise penalise ½ mark </em><em>for</em> <em>arithmetic</em> <em>error</em> <em>outside</em> <em>+2</em> <em>marks</em> <em>in</em> <em>the</em> <em>1<sup>st</sup></em> <em>p</em></li>
<li><em>Penalise ½ mark for wrong transfer of ans in (c) or (b) in both otherwise penalise fully for </em><em>strange figure in either</em></li>
</ul>
<p> ;</p>
<p><em>NB: Penalise fully for any calculation noted beyond the expected ans.</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="62"><em>2</em></td>
<td width="278"><strong><em>Observation</em></strong></td>
<td width="459"><strong><em>Inferences</em></strong></td>
</tr>
<tr>
<td width="62"><em>a (i)</em></td>
<td width="278"><em>White ppt</em></td>
<td width="459"><em>B</em><em><sup>2</sup></em><em><sup>+</sup></em><em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em><sup>,</sup></em> <em>B</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em><sup>,</sup></em> <em>I</em><em>f</em> <em>a</em><em>l</em><em>l</em> <em>t</em><em>h</em><em>e</em> <em>3</em> <em>g</em><em>i</em><em>ve</em><em>n</em> <em>2</em> <em>m</em><em>a</em><em>r</em><em>ks If only 2 given – 1 mark</em></p>
<p><em>If only 1 given – ½ mark</em></p>
<p><strong><em><u>Note</u></em></strong><em>: for any contradictory mark out of 1 ½ ,penalize ½ mark for any contradictory</em></td>
</tr>
<tr>
<td width="62"><em>ii)</em></td>
<td width="278"><em>White ppt which dissolves in excess.</em></p>
<p><em>reject residue </em><em>Suspension Accept white solid</em></td>
<td width="459"><em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>N</em><em>B</em><em>:</em> <em>C</em><em>r</em><em>e</em><em>d</em><em>i</em><em>t</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em> <em>o</em><em>n</em><em>l</em><em>y</em> <em>i</em><em>f</em> <em>m</em><em>e</em><em>n</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>i</em><em>n</em> <em>(</em><em>i</em><em>)</em> <em>a</em><em>bove</em><em>,</em> <em>penali</em><em>z</em><em>e </em><em>fully for any contradiction</em></td>
</tr>
<tr>
<td width="62"><em>iii)</em></td>
<td width="278"><em>White</em> <em>PPt</em></td>
<td width="459"><em>&#8211;</em><em>F</em> <em>c</em><em>o</em><em>n</em><em>t</em><em>a</em><em>i</em><em>n</em><em>s</em> <em>S</em><em>O</em> <em><sup>2</sup></em><em><sup>&#8211;</sup></em><em>,</em> <em>C</em><em>l</em><em><sup>&#8211;</sup></em><em>,</em> <em>S</em><em>O</em> <em><sup>2</sup></em><em><sup>&#8211;</sup></em><em><sup>,</sup></em> <em>C</em><em>l</em><em><sup>&#8211;</sup></em><em>,</em> <em>o</em><em>r</em> <em>S</em><em>O</em> <em><sup>2</sup></em><em><sup>&#8211;</sup></em><em><sup>,</sup></em> <em>C</em><em>l</em><em><sup>&#8211;</sup></em><em>,</em></p>
<p><em>4 3 4</em></p>
<p><em>SO <sup>2-</sup>, CO <sup>2-</sup>, 4 ions given – 1 mark</em></p>
<p><em>3 3</em></p>
<p><em>3 or 2 ions given – ½ mark ions given – 0 mark</em></p>
<p><em>Penalties</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="62"> ;</td>
<td width="278"> ;</td>
<td width="459"><em>Penalise fully if candidate E contains the above ions </em><em>–</em></p>
<p><em>penalize ½ mark for contradictory ions</em></td>
</tr>
<tr>
<td width="62"><em>iv)</em></td>
<td width="278"><em>Yellow PPt</em></td>
<td width="459"><em>Pb</em><em>2+</em></p>
<p><em>Penalise fully for any contradictory ions</em></td>
</tr>
<tr>
<td width="62"><em>bi)</em></td>
<td width="278"><em>Burns with a smoky/sooty </em><em>flame/sooty flame Accept – yellow sooty</em></td>
<td width="459"><em> </em></p>
<p><em>&#8211; C=C- / -C=C-</em></p>
<p><em>A</em><em>cc</em><em>e</em><em>p</em><em>t</em> <em>;</em> <em>l</em><em>o</em><em>n</em><em>g</em> <em>c</em><em>h</em><em>a</em><em>i</em><em>n</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>a</em><em>r</em><em>bon</em><em>, </em><em>carbon; hydrogen ratio</em></p>
<p><em>Penalise fully for any contradictory functional group.</em></td>
</tr>
<tr>
<td width="62"><em>(ii) <strong>I</strong></em></td>
<td width="278"><em>I pH is 1 or 3 accept red for ½ mk but reject inference given but reject inference given on its strength Reject PH range, penalize Fully for colour and correct</em></p>
<p><em>PH NB: If a wrong colour</em></td>
<td width="459"><em>strongly</em> <em>acidic</em></p>
<p><em>Reject – acidic given alone G – is a strong acid</em></p>
<p><em>ignore – carboxylic acid</em></td>
</tr>
<tr>
<td width="62"><strong><em>II</em></strong></td>
<td width="278"><em>KMnO</em><em>4 </em><em>decolourised Or KMnO</em><em>4 </em><em>turns from </em><em>Purple to colourless Reject</em></p>
<p><em>KMnO</em><em>4 </em><em>turns colourless </em><em>Solution</em> <em>turns</em> <em>colourless Solution decolourised</em></p>
<p><em>Solution</em> <em>discolurised</em></td>
<td width="459"><em> </em></p>
<p><em>&#8211; C = C- or – C <u>=</u> C- R – OH ½</em></p>
<p><em>Reject the groups in words – OH Penalise ½ mk for each contractor functional group</em></td>
</tr>
<tr>
<td width="62"><em>iii</em></td>
<td width="278"><em>Effervescence /bubbles /fizzing odourless gas</em></p>
<p><em>odourless to differentiate between </em><em>SO</em><em>2 </em><em>&; CO</em><em>2</em></p>
<p><em>Reject</em> <em>; </em><em>Hissing</em></p>
<p><em>Odourless</em> <em>mentioned alone</em></td>
<td width="459"><em>CO <sup>2-</sup> present in F (tied to part (a) (iii)</em></p>
<p><em>3</em></p>
<p><em>Ignore</em> <em>mention</em> <em>of</em> <em>acid</em></p>
<p><em>ii). Penalise fully for contradiction iii).The inference is tied to effervescence </em><em>bubbles and odourless</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2011 MARKSCHEME</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Conditions (ii)</em></strong></p>
<ol>
<li><em>Value 1.60 must be intact otherwise penalize fully</em></li>
<li><em> Should be at least 3 dec. place</em></li>
<li><em>Penalise ½ mark for arithmetic error if outside + 2 units in the 3<sup>rd</sup> depth</em></li>
</ol>
<p> ;</p>
<ol>
<li><em>Units may not be given but if given must be correct penalize ½ mark for errors units used</em></li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="315"> ;</td>
<td width="128"><strong><em>1</em></strong></td>
<td width="135"><strong><em>2</em></strong></td>
<td width="152"><strong><em>3</em></strong></td>
</tr>
<tr>
<td width="315"><em>Final burette reading</em></td>
<td width="128"><em>29.70</em></td>
<td width="135"><em>33.40</em></td>
<td width="152"><em>44.60</em></td>
</tr>
<tr>
<td width="315"><em>Initial burette reading</em></td>
<td width="128"><em>0.00</em></td>
<td width="135"><em>4.00</em></td>
<td width="152"><em>15.30</em></td>
</tr>
<tr>
<td width="315"><em>Volume of solution A used (cm<sup>3</sup>)</em></td>
<td width="128"><em>29.70</em></td>
<td width="135"><em>29.40</em></td>
<td width="152"><em>29.30</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>ii). <strong>Concentration in moles per litre of the dibasic acid in solution A </strong></em><em>Relative molecular mass of A is 126.</em></p>
<p><em><u>1.60</u></em> <em>x 1000 <u>1.60</u> <u>1.60</u> x <u>1000</u> <u>1.60</u> x 4</em></p>
<p><em>250 </em><em>= 6.4 126 = 0.0127 126 126 126</em></p>
<p><em><u>6.4</u></em><em> moles in a litre = 0.051M</em></p>
<p> ;</p>
<p><em>126 = 0.05 <u>0.0127</u> x 1000</em></p>
<p><em>250</em></p>
<p><em>= 4 x 0.00127</em></p>
<p><em>= 0.051</em></p>
<p> ;</p>
<ul>
<li><em>M</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>t</em><em>h</em><em>e</em> <em>d</em><em>i</em><em>ba</em><em>s</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>; </em><em><u>Answer in (ii) above x litre</u></em></li>
</ul>
<p><em>1000</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>2</em> <em>marks</em></p>
<p> ;</p>
<p><em>= correct answer 1 mark</em></p>
<p> ;</p>
<ul>
<li><em>M</em><em>o</em><em>l</em><em>e</em><em>s</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em><em>,</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>x</em><em>i</em><em>d</em><em>e</em> <em>i</em><em>n</em> <em>25</em><em>.</em><em>0</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C </em><em>Ans in (iii) above x 2</em></li>
</ul>
<p><em>=correct answer</em></p>
<p><em>1 mark</em></p>
<ul>
<li><em>Concentration of sodium hydroxide in moles per litre</em></li>
</ul>
<p><em><u>Answer (iv) above x 1000</u></em><em> Answer (iv) above x 40 25</em></p>
<p><em>Correct</em> <em>answer Or <u>Mb = Ans (iv) above x titre x 2</u> 25</em></p>
<p><em>Correct</em> <em>answer</em></p>
<p><em>Or Ans (iv) x titre Mb x 25</em></p>
<p><em>= Correct answer</em></p>
<p> ;</p>
<ul>
<li><strong><em>Calculate the;</em></strong>
<ul>
<li><em>A</em><em>ve</em><em>r</em><em>a</em><em>g</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>A</em> <em>u</em><em>s</em><em>e</em><em>d</em><em>;</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="331"> ;</td>
<td width="158"><strong><em>1<sup>st</sup> Conical flask</em></strong></td>
<td width="188"><strong><em>2<sup>nd</sup> Conical Flask</em></strong></td>
</tr>
<tr>
<td width="331"><em>Final burette reading</em></td>
<td width="158"><em>21.20</em></td>
<td width="188"><em>33.60</em></td>
</tr>
<tr>
<td width="331"><em>Initial burette reading</em></td>
<td width="158"><em>9.70</em></td>
<td width="188"><em>21.20</em></td>
</tr>
<tr>
<td width="331"><em>Volume of solution A used (cm<sup>3</sup>)</em></td>
<td width="158"><em>11.50</em></td>
<td width="188"><em>11.40</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<ul>
<li><em>Moles of the dibasic acid used: Ans (ii) procedure II x titre (table 2)</em></li>
</ul>
<p><em>1000</em></p>
<p><em>= Correct ans</em></p>
<p> ;</p>
<ul>
<li><em>Moles of sodium hydroxide that reacted with the dibasic acid</em></li>
</ul>
<p><em>= Ans (ii) above x 2</em></p>
<p><em>= Correct ans</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>1 mark</em></p>
<p> ;</p>
<p> ;</p>
<p><em>1 mark</em></p>
<p> ;</p>
<ul>
<li><em>Moles of sodium hydroxide that reacted with 0cm<sup>3</sup> of salt B in solution B;</em></li>
</ul>
<p><em>=Ans (iv) procedure II = Ans (iii) above</em></p>
<p><em>=Correct</em> <em>ans.</em></p>
<p><em>2 marks v). <strong>Given that I mole of salt B reacts with 2 moles of sodium hydroxide, calculate the;</strong></em></p>
<ol start="25">
<li><em>Number of moles of salt B in 0cm3 of solution B <u>Ans (iv) above</u></em></li>
</ol>
<p><em>2</em></p>
<p><em>Correct ans</em></p>
<p><em>1 mark</em></p>
<ol>
<li><em>Concentration in moles per litre of salt B in solution B </em><em>Ans I above x 1000</em></li>
</ol>
<p><em>25</em></p>
<p> ;</p>
<p><em>Ans I above x 40</em></p>
<p><em>= Correct ans</em></p>
<p> ;</p>
<ul>
<li><em>Relative</em> <em>molecular</em> <em>mass</em> <em>of</em> <em>salt</em> <em>B;</em></li>
</ul>
<p><em>= <u>4.75</u></em></p>
<p><em>Ans in II above</em></p>
<p><em>= Correct answer >; and >; 140 penalise ½ mark for ans</em></p>
<p> ;</p>
<ol start="2">
<li><em> a).i). <strong>Observation Inferences</strong></em></li>
</ol>
<p><strong> </strong></p>
<p><em>1 mark</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Gas</em> <em>that</em> <em>turns</em> <em>moist</em> <em>litmus</em> <em>paper </em><em>NH <sup>+</sup> present (tied to red litmus Blue given off </em><em>turning blue)</em></p>
<p><em>Condenses on the cooler parts of Solid D is hydrated /Solid D</em></p>
<p><em>The tube to form colourless liquid contains water of crystallisation </em><em>Droplets (tied to idea of condensation)</em></p>
<p><em>White sublimate formed solid Sublimes to form white sublimate</em></p>
<p><em>A</em> <em>gas</em> <em>given</em> <em>off</em> <em>that</em> <em>turns</em> <em>moist blue Litmus paper red</em></p>
<p><em>A brown residue /solid formed</em></p>
<p><em>NB: Ignore mention of any other ions present</em></p>
<p> ;</p>
<ul>
<li><strong><em>Observations Inferences</em></strong></li>
</ul>
<p><em>Yellow /brown solution formed Fe<sup>2+</sup> oxidized to Fe<sup>3+</sup> </em><em>On</em><em> </em><em>addition</em><em> </em><em>of H</em><em>2 </em><em>O</em><em>2 </em><em>solution or</em></p>
<p><em>Brown</em> <em>ppt</em> <em>formed</em> <em>which</em> <em>is</em> <em>in</em> <em>soluble </em><em>Fe<sup>3+</sup> formed</em></p>
<p><em>In excess NaOH solution NB: ignore Accept Fe<sup>3+</sup> present in Mention of initial colour of solution mixture of Fe<sup>2+</sup> in</em></p>
<p><em>unless</em> <em>It</em> <em>contradictory </em><em>solution</em></p>
<p><em>NB:</em> <em>Reject</em> <em>Fe<sup>3+</sup></em> <em>present</em> <em>/solid</em> <em>or</em> <em>solution</em> <em>D</em> <em>contains</em> <em>Fe<sup>3+</sup></em></p>
<p> ;</p>
<p><strong><em>b). </em></strong><em>i). </em><strong><em>Observations Inferences</em></strong></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>A white ppt formed </em><em>SO <sup>2-,</sup> SO <sup>2-</sup> CO <sup>2-</sup> present</em></p>
<p><em>NB:</em> <em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>each contradictory ions for a max of ( 1 ½ mark)</em></p>
<p> ;</p>
<p><em>ii). To the mixture obtained in (i) above, add about 5 cm<sup>3</sup> of 2M nitric acid (V) acid </em><strong><em>Observations Inferences</em></strong></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Effervesces occurs /bubbles of SO <sup>2-</sup> presents</em></p>
<p><em>Gas seen</em></p>
<p><em>The white ppt dissolves disappears NB: credit only if correctly inferred Correct inference tied to either observation or both</em></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>each</em> <em>contrition</em> <em>to</em> <em>a max of 1 mark Ignore SO <sup>2</sup> mentioned as absent</em></p>
<ul>
<li><em>T</em><em>o</em> <em>po</em><em>r</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>t</em><em>w</em><em>o</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>E</em> <em>i</em><em>n</em> <em>a</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>,</em> <em>a</em><em>d</em><em>d</em> <em>2</em> <em>d</em><em>r</em><em>o</em><em>p</em><em>s</em> <em>o</em><em>f</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>i</em><em>f</em><em>i</em><em>e</em><em>d</em> <em>po</em><em>t</em><em>a</em><em>ss</em><em>i</em><em>u</em><em>m</em> <em>d</em><em>i</em><em>c</em><em>h</em><em>r</em><em>o</em><em>m</em><em>a</em><em>t</em><em>e</em></li>
</ul>
<p><em>(VI) and warm the mixture</em></p>
<p> ;</p>
<p><strong><em>Observations Inferences</em></strong></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>3</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Acidified</em><em> </em><em>K</em><em>2</em><em>Cr</em><em>2</em><em>O</em><em>7</em> <em>solution </em><em>SO <sup>2-</sup> presents</em></p>
<p><em>Changes from orange to green NB: credit only if correctly inferred Correct inference tied to either observation or both</em></p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Penalise</em> <em>½</em> <em>mark</em> <em>for</em> <em>each</em> <em>contrition</em> <em>to</em> <em>a max of 1 mark Ignore SO <sup>2</sup> mentioned as absent</em></p>
<p> ;</p>
<p><em>3 <strong>a). Observations inferences</strong></em></p>
<p> ;</p>
<p><em>Burns with a blue flame </em><em>Reject C = C / C C abs<span style="text-decoration: line-through;"><u>en</u></span>t</em></p>
<p><em>Saturated</em> <em>organic</em> <em>compound/organic Compound with low C: H ratio</em></p>
<p><em>Absence of unsaturated organic compound Ignore R-OH if mentioned</em></p>
<p> ;</p>
<ul>
<li><strong><em>Observations Inferences</em></strong></li>
</ul>
<p><em>No of effervescence /No bubbles Absence of H<sup>+</sup> or liquid is not acidic</em></p>
<p><em>/No of fizzing</em></p>
<p><em>Ignore does not dissolved Absence of R- COOH</em></p>
<p><em>No reaction Ignore H</em><em>3</em><em>O<sup>+</sup></em><em> </em><em>if</em><em> </em><em>mentioned</em><em> </em><em>R</em><em>e</em><em>j</em><em>e</em><em>c</em><em>t</em><em>:</em> <em>N</em><em>o</em> <em>h</em><em>i</em><em>ss</em><em>i</em><em>n</em><em>g</em> <em>o</em><em>n</em> <em>i</em><em>t</em><em>’</em><em>s</em> <em>o</em><em>w</em><em>n</em></p>
<p> ;</p>
<ul>
<li><strong><em>Observations Inferences </em></strong><em>K</em><em>2</em><em>Cr</em><em>2</em><em>O</em><em>7 </em><em>changes from orange to R &#8211; OH</em></li>
</ul>
<p><em>green/solution changes from orange Reject; 1 – alcohol written in to green words 2-OH</em></p>
<p> ;</p>
<p><em>R</em><em>e</em><em>j</em><em>e</em><em>c</em><em>t</em><em>:</em> <em>s</em><em>o</em><em>l</em><em>n</em> <em>t</em><em>u</em><em>r</em><em>n</em><em>s</em> <em>g</em><em>r</em><em>ee</em><em>n</em><em>,</em> <em>N</em><em>B</em><em>:</em> <em>P</em><em>e</em><em>n</em><em>a</em><em>l</em><em>i</em><em>s</em><em>e</em> <em>f</em><em>u</em><em>ll</em><em>y</em> <em>f</em><em>o</em><em>r</em> <em>a</em><em>n</em><em>y</em> <em>c</em><em>o</em><em>n</em><em>t</em><em>r</em><em>a</em><em>d</em><em>i</em><em>c</em><em>t</em><em>i</em><em>n</em><em>g</em> <em>f</em><em>u</em><em>n</em><em>c</em><em>t</em><em>i</em><em>o</em><em>n</em><em>a</em><em>l</em> <em>g</em><em>r</em><em>o</em><em>u</em><em>p</em><em>s</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>NOVEMBER 2012 MARKSCHEME</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><strong><em>Question I – Procedure</em></strong>
<ul>
<li><strong><em>i). Moles of Sodium thiosulphate (Solution B) </em></strong><em><u>05 x Average titre</u></em></li>
</ul>
</li>
</ol>
<p><em>1000</em></p>
<p><em>= Correct answer <strong>Conditions</strong></em></p>
<p><strong> </strong></p>
<ul>
<li><em>i). Moles of solution A in 0cm<sup>3</sup></em></li>
</ul>
<p><em>Moles ratio moles of A : Moles of Na</em><em>2</em><em>S</em><em>2</em><em>O</em><em>3 </em><em>. 5H</em><em>2</em><em>O </em><em>1 :</em><em> </em><em>6</em></p>
<p><em>Moles of A = 1</em></p>
<p><em>Moles of Na</em><em>2</em><em>SO</em><em>3 </em><em>SH</em><em>2</em><em>O </em><em>Moles of A = <u>ans a (ii) moles</u></em></p>
<p><em>6 = Correct answer ii). Concentration of A in moles per litre</em></p>
<p><em>25cm<sup>3</sup> of A contains ans b(i) above 1000 cm<sup>3</sup> of A contains</em></p>
<p><em><u>Ans b(i) x 1000</u></em></p>
<p><em>25</em></p>
<p><em>= correct answer OR</em></p>
<p><em>Ans b(i) x 40</em></p>
<p><em>= Correct answer</em></p>
<p> ;</p>
<p><em>OR </em><em><u>M</u></em><em><u>A </u></em><em><u>V</u></em><em><u>A </u></em><em>=<u> 1</u> </em><em>M</em><em>B </em><em>V</em><em>B</em><em> </em><em>6</em></p>
<p><em>M</em><em>A </em><em>= <u>0.05 x Average titre</u></em></p>
<p><em>6 x 25</em></p>
<p><em>= Correct answer</em></p>
<p> ;</p>
<p><em>OR</em></p>
<p><em><u>Answer (b) (i) x 1000</u></em> <em>= Correct answer</em></p>
<p><em>25</em></p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Penalise ½ mark fro wrong transfer of ans b(ii) or average titre otherwise </em><em>penalise fully for strange figure</em></li>
<li><em>Answer must be given to at least 3 p unless it works out exactly to less than 3</em></li>
</ul>
<p><em>d.p otherwise penalise ½ mark</em></p>
<ul>
<li><em>Penalise ½ mark for answer if arithmetic error is outside +2 units in the 3<sup>rd</sup>p </em><em>d). Units may not be given but if given must be correct otherwise penalise ½ mark</em></li>
</ul>
<p><em>for wrong units used</em></p>
<p><em>e). When formula is wrongly given in the formula method penalise fully <strong><u>NB:</u> </strong>Penalise ½ mark for the answers in calculation a (i) and b (ii) if</em></p>
<p><em>candidate work beyond the expected answer</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>PROCEDURE II</em></strong></p>
<p><strong><em>Table 2 – 6 marks Distribution of marks</em></strong></p>
<p><em>Complete table …………………………………………. </em><em>(3 marks)</em></p>
<p> ;</p>
<ol>
<li><strong><em>ACCURACY</em></strong></li>
</ol>
<p><em>Compare the candidates 1<sup>st</sup> time reading to the S.V if within +2s award 1mk otherwise penalise </em><em>fully</em></p>
<p><strong><em>Note:</em></strong></p>
<ul>
<li><em>The V is the teacher first time reading</em></li>
<li><em>Put a tick (√ ) on the candidate value if right</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>TREND (Tied to the time row)</em></strong></li>
</ol>
<p><em>Award (1 mark) for time reading increasing continuously otherwise penalise fully</em></p>
<p> ;</p>
<p><strong><em>Graph</em></strong></p>
<ol>
<li><strong><em>Labelling </em></strong><em>Conditions</em>
<ul>
<li><em>A</em><em>cc</em><em>e</em><em>p</em><em>t</em> <em>l</em><em>a</em><em>belin</em><em>g</em> <em>eve</em><em>n</em> <em>i</em><em>f</em> <em>n</em><em>o</em> <em>u</em><em>n</em><em>i</em><em>t</em><em>s</em> <em>a</em><em>r</em><em>e</em> <em>s</em><em>h</em><em>o</em><em>wn</em><em>,</em> <em>o</em><em>t</em><em>he</em><em>r</em><em>wi</em><em>s</em><em>e</em> <em>penali</em><em>s</em><em>e</em> <em>f</em><em>u</em><em>ll</em><em>y</em> <em>i</em><em>f</em> <em>w</em><em>r</em><em>o</em><em>n</em><em>g</em> <em>u</em><em>n</em><em>i</em><em>t</em><em>s</em> <em>a</em><em>r</em><em>e </em><em>shown</em></li>
<li><em>Penalise fully for inverted axis</em></li>
<li><em>Penalise fully if only one axis is correctly labeled</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<ol>
<li><strong><em>Scale</em></strong></li>
</ol>
<ul>
<li><em>Area covered by the actual plots (including the origin) must be at least 4 x 4 large </em><em>squares ( ½ the grid) otherwise penalise fully</em></li>
<li><em>The scale internal must be consistent on each axis iii). The scale chosen must accommodate all the plots <strong>Note:</strong></em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="42"> ;</td>
<td width="377"><em>Penalise fully if any of the above is not met Award for the scale even if the axis are inverted</em></td>
<td width="136"> ;</td>
</tr>
<tr>
<td width="42"><strong><em>C.</em></strong></td>
<td width="377"><strong><em>Plotting Conditions</em></strong></p>
<p><em>If 5 or 6 points are correctly plotted ……………….</em></td>
<td width="136"><strong><em> </em></strong></p>
<p><strong><em> </em></strong></p>
<p><em>(1 mark)</em></td>
</tr>
<tr>
<td width="42"> ;</td>
<td width="377"><em>If 3 or 4 points are correctly plotted …………</em></p>
<p><em>If less than 3 points ……………………………</em></td>
<td width="136"><em>(½ mark)</em></p>
<p><em>(0 marks)</em></td>
</tr>
</tbody>
</table>
<p><strong> </strong></p>
<ol>
<li><strong><em> Line</em></strong></li>
</ol>
<p><em>Accept a straight line passing through at least 2 points correctly plotted and through the origin on </em><em>extrapolation otherwise penalise fully</em></p>
<p> ;</p>
<p><strong><em>Calculations</em></strong></p>
<p><em>i). For correct showing of <sup>i</sup>/</em><em>t </em><em>on the graph ½ mark </em><em>ii). For stating the correct reading</em></p>
<p><em>e.g R = 0.003</em></p>
<p><em>iii). For t = 1/correct value</em></p>
<p><em>v). Correct value ½ (Must have units)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Accept</em> <em>correct</em> <em>readings without showing</em></li>
<li><em>Award ½ mark for showing on the graph and 1 If applied correctly in the expression and ½ </em><em>mark for the answer</em></li>
<li><em>Answer must be at</em> <em>at least 1 p or whole no (if it works out) otherwise penalise</em></li>
<li><em>Allow</em> <em>showing</em> <em>of</em> <em>reading</em> <em>for</em> <em>the</em> <em>candidates</em> <em>graph</em> <em>irrespective</em> <em>of the line as long as the scale is correct(Intervals)</em></li>
<li><em>Award where not shown not stated but correct reading if done for him/her (do it)</em></li>
</ul>
<p> ;</p>
<p><strong><em>Penalise</em></strong></p>
<p><em>Penalise ½ mark for W.A if the answer is not within +2 units in the 1<sup>st</sup> d.p </em><em>Correct units must be shown otherwise penalise ½ mark</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="41"><strong><em>2.</em></strong></td>
<td width="70"><strong><em>a).i).</em></strong></td>
<td width="55"><strong><em>I).</em></strong></td>
<td width="212"><strong><em>Observations</em></strong></p>
<p><em>A</em> <em>white</em> <em>precipitate</em></td>
<td width="395"><strong><em>Inferences</em></strong></p>
<p><em>P</em><em>r</em><em>e</em><em>s</em><em>e</em><em>n</em><em>c</em><em>e</em> <em>o</em><em>f</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>B</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em><em>,</em> <em>C</em><em>a</em><em><sup>2</sup></em><em><sup>+</sup></em> <em>Only 2 – ½ mark</em></p>
<p><em>Penalise ½ mark for each contradictory ion</em></td>
</tr>
<tr>
<td width="41"> ;</td>
<td width="70"> ;</td>
<td width="55"><strong><em>II).</em></strong></td>
<td width="212"><strong><em>Observations </em></strong><em>No white ppt</em></td>
<td width="395"><strong><em>Inferences</em></strong></p>
<p><em>P</em><em>r</em><em>e</em><em>s</em><em>e</em><em>n</em><em>c</em><em>e</em> <em>o</em><em>f</em><em> Ba<sup>2+</sup>, Ca<sup>2+</sup></em></p>
<p><em>Pb<sup>2+</sup></em> <em>absent ½ where the above</em></p>
<p><em>Not mentioned penalise ½ mark for each </em><em>contradictory ions</em></td>
</tr>
<tr>
<td width="41"> ;</td>
<td width="70"> ;</td>
<td width="55"><strong><em>III).</em></strong></td>
<td width="212"><strong><em>Observations</em></strong></p>
<p><em>No white precipitate</em></td>
<td width="395"><strong><em>Inferences </em></strong><em>Cl- absent</em></p>
<p><em>Penalise fully for any contradictory ion</em></p>
<p><em>Ignore mention of S0 <sup>2-</sup>, SO <sup>2</sup> of CO <sup>2-</sup> as absent</em></p>
<p><em>4 3 3</em></td>
</tr>
</tbody>
</table>
<p><em>ii). <strong>Observations</strong></em></p>
<p><em>Effervescence/bubbled Solid contain NO</em><em>3</em></p>
<p><em>Colourless gas/pungent choking (Tied to red litmus turning blue)</em></p>
<p> ;</p>
<p><em>Smell</em></p>
<p><em>Red Litmus – blue Blue – remains blue</em></p>
<p> ;</p>
<ol start="3">
<li><em> a). <strong>Observations Inferences</strong></em></li>
</ol>
<p><em>No effervescence/no bubbles Solid F is not acidic No fizzing OR</em></p>
<p><em>Absence of H+/H30+</em></p>
<ul>
<li><em>i). <strong>Observations Inferences</strong></em></li>
</ul>
<p><em>Burns with a sooty flame Unsaturated /long chain /high C-H organic cpd organic cpds ratio present</em></p>
<p><em>S</em><em>m</em><em>o</em><em>ky flame or luminous Flame / Carbon –carbon double/triple Yellow flame bond written in words or aromatic cpds</em></p>
<p> ;</p>
<p><em>ii). <strong>Observations Inferences</strong></em></p>
<p><em>White suspensions Compound is slightly soluble Or Or</em></p>
<p><em>White solid remains undissolved Cpd is partially soluble</em></p>
<p><em>or</em></p>
<p><em>cpd</em> <em>is</em> <em>insoluble/cpd</em> <em>is nonpolar</em></p>
<p> ;</p>
<ul>
<li><em>i). <strong>Observations Inferences </strong>Effervescence /Bubbles /fizzing The mixture is acidic</em></li>
</ul>
<p><em>Or Or</em></p>
<p><em>Accept colorless gas given off RCOOH or H<sup>+</sup>/H</em><em>3</em><em>O present</em></p>
<p><em>ii). <strong>Observations Inferences</strong></em></p>
<p><em>Bromine</em> <em>water</em> <em>is</em> <em>not</em> <em>decolourised </em><em>Carbon – carbon double/triple </em><em>Or bond absent</em></p>
<p><em>Yellow/orange/brown/red </em><em>Or</em></p>
<p><em>Remains persists Compound is saturated Bromine water remain yellow</em></p>
<p> ;</p>
<p><strong><em>NOVEMBER 2013 MARKSCHEME</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Procedure I. </em></strong><strong><em>Table 1.</em></strong></p>
<ol>
<li><em>Complete table (All readings recorded) ……….</em>
<ul>
<li><em>Penalise</em> <em>½</em> <em>mark</em> <em>once</em> <em>for</em> <em>any</em> <em>space</em> <em>not</em> <em>filled,</em> <em>subject</em> <em>to</em> <em>at</em> <em>least</em> <em>4</em> <em>readings</em> <em>beings given otherwise penalize</em></li>
<li><em>Penalise ½ mark for unrealistic temperature reading either below 10<sup>0</sup>C or more than 40<sup>0</sup>C </em><em>at t=0</em></li>
<li><em>P</em><em>e</em><em>n</em><em>a</em><em>l</em><em>i</em><em>s</em><em>e</em> <em>½</em> <em>m</em><em>a</em><em>r</em><em>k for temperature reading, they should all be constant from t=0 to t=7 iv). If two or more rows of temperature readings are given, penalize ½ mark for complete</em></li>
</ul>
</li>
</ol>
<p><em>table based on the rows used to plot the graph. However if the graph is not drawn then </em><em>mark the first rows of the temperature reading.</em></p>
<p><em>v). If two or more graphs are plotted, mark the complete table based on the first row.</em></p>
<p> ;</p>
<ol>
<li><em>Use of decimals (tied to at least two readings) accept the temperature reading for ½ mark only if </em><em>consistently given as either 1 o</em></li>
</ol>
<p><em>i). Whole number ii). 1 decimal point of either ‘0’ or ‘5’ Otherwise penalize fully</em></p>
<p> ;</p>
<ul>
<li><em>Accuracy…………………………….</em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="50">
<table width="100%">
<tbody>
<tr>
<td><em>hemistr</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<table>
<tbody>
<tr>
<td width="34">
<table width="100%">
<tbody>
<tr>
<td><em>2016</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>Compare the candidate temperature reading at t=0 with the school value (S.V) and award ½ mark. </em><em>If the reading is within +2C of the S.V otherwise penalize fully</em></p>
<p><em>Trend …..</em></p>
<p> ;</p>
<p><em><u>A</u></em><em><u>wa</u></em><em><u>r</u></em><em><u>d</u></em><em><u>e</u></em><em><u>d</u></em> <em><u>a</u></em><em><u>s</u></em> <em><u>f</u></em><em><u>o</u></em><em><u>ll</u></em><em><u>o</u></em><em><u>w</u></em><em><u>s</u></em><em><u>;</u></em></p>
<ul>
<li><em>½</em> <em>mark</em> <em>for</em> <em>continuous</em> <em>rise</em> <em>upto</em> <em>the</em> <em>maximum</em></li>
<li><em>2<sup>nd</sup> ½ mark for temperature being either content at maximum or constant followed by a </em><em>continuous drop or continuous drop after </em></li>
</ul>
<p><strong><em>Graph……</em></strong></p>
<p><strong><em>Distribution as follows.</em></strong></p>
<ol>
<li><strong><em>correct labeling of both axes ………………………..</em></strong></li>
</ol>
<p><strong><em>Penalties</em></strong></p>
<ul>
<li><em>Penalise fully for inverted axes</em></li>
<li><em>Penalise fully for wrong units used other ignore if units are omitted </em><em>iii). Penalise fully if only one axis labeled</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em> Scale……………………………………………….</em></strong></li>
</ol>
<p><em>i). Area covered by plot should be atleast half of grid provided i.e 4 ½ by 3 ii). Scale interval should be consistent each axis</em></p>
<p><em>iii). All plots/points whether plotted or not (check the range of reading on the note. Penalise fully if any of the above conditions is not met</em></p>
<ul>
<li><strong><em>Plotting……………………………..</em></strong></li>
</ul>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>If 8 or 7 correctly plotted ………</em></li>
<li><em>If only 6 to 4 points correctly plotting </em><em>iii). If less than 4 points correctly plotted …. Note:</em></li>
</ul>
<ul>
<li><em>If the scale interval changes mark plots if any within the first scale interval and the first </em><em>as wrong</em></li>
<li><em>Accept correct plots even if the axes are inverted and award accordingly </em><em>iii). Mark all plots on the graph to verify the award</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Line/Shape………….</em></strong></li>
</ol>
<ul>
<li><em>Accept 2 straight lines intersecting on extrapolation for ……………….</em></li>
<li><em>Accept 2 straight lines not extrapolated whether joined or not for…</em></li>
<li><em>Accept 1<sup>st</sup> line of best fit only if it passes through the initial temperature the following are </em><em>the versions accepted even if the axes are </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Highest change in temperature, OT.</em></strong></p>
<ol>
<li><em>i). Accept correct value of OT from correctly extrapolated graph</em></li>
</ol>
<p><em>with/without showing</em><em>&#8230;&#8230;&#8230;&#8230;. </em><em>Provided 1<sup>st</sup> line passes through the plot at t=0 i.e limited</em></p>
<p><em>temperature.</em></p>
<p><em>ii). Award ½ mark for correct showing on a correctly DT value is wrong or missing iii). Award 0 max for DT stated from a wrong graph</em></p>
<p><em>Note: a). </em><em>Ignore +ve or –ve sign on the DT value</em></p>
<p><em>b). Penalise ½ mark for wrong units otherwise ignore if omitted</em></p>
<p> ;</p>
<ol>
<li><em>Time taken for reaction to be completed</em></li>
</ol>
<p><em>Accept correct time reading from correctly extrapolated with or without showing for …. If wrong units of time are given penalize fully, otherwise ignore omission of units</em></p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>I</em><em>g</em><em>n</em><em>o</em><em>r</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>o</em><em>r</em><em>m</em><em>u</em><em>l</em><em>a</em> <em>f</em><em>o</em><em>r</em> <em>wo</em><em>r</em><em>king DH, but if given MUST be correct otherwise penalize ½ mark where wrong formula is given</em></li>
<li><em>Penalise ½ mark for wrong units or omission of units on the answer iii). Accept correct transfer of DT even if rejected in a(iii) I above</em></li>
</ul>
<p><em>iv). Penalise ½ mark for wrong arithmetic on answer if it is outside + 200 joules or + 0.2 KJ iv). Ignore if no sign is given on the answer otherwise penalize ½ mark for positive sign (+)</em></p>
<p> ;</p>
<p><strong><em>Procedure II</em></strong></p>
<p><strong><em>Table 2 …………………….</em></strong></p>
<ol>
<li><strong><em> Complete table ………………………</em></strong></li>
</ol>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>Complete table with 3 titrations done</em></li>
<li><em>Incomplete table with 2 titrations done ……..</em></li>
<li><em>Incomplete table with only one titration ……………….</em></li>
</ul>
<p> ;</p>
<p><strong><em>Penalties</em></strong></p>
<p><em>i). Wrong arithmetric when determining the titre values ii). Inverted tables</em></p>
<ul>
<li><em>Burette readings </em><em>beyond 50ml unless explaining iv). Unrealistic titre values below 1 ml or in hundreds v). Penalise ½ mark for each to a maximum of ½ mark</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<ol>
<li><strong><em> TABLE 2 ………………………</em></strong></li>
</ol>
<p><strong><em>Use of decimals …. Tied to 1<sup>st</sup> row and 2<sup>nd</sup> row only</em></strong></p>
<p> ;</p>
<p><strong><em>Conditions</em></strong></p>
<ul>
<li><em>A</em><em>cc</em><em>e</em><em>p</em><em>t</em> <em>1</em> <em>d</em><em>p or 2 dp used consistently; otherwise penalize fully</em></li>
<li><em>I</em><em>f</em> <em>2</em> <em>d</em><em>p</em><em>t</em><em>s</em> <em>a</em><em>r</em><em>e</em> <em>u</em><em>s</em><em>e</em><em>d</em> <em>t</em><em>h</em><em>e</em> <em>s</em><em>e</em><em>c</em><em>o</em><em>n</em><em>d</em> <em>d</em><em>e</em><em>c</em><em>i</em><em>m</em><em>a</em><em>l</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em> <em>m</em><em>u</em><em>s</em><em>t</em> <em>b</em><em>e</em> <em>‘</em><em>O</em><em>’</em> <em>o</em><em>r</em> <em>‘</em><em>S</em><em>’</em> <em>o</em><em>t</em><em>he</em><em>r</em><em>wi</em><em>s</em><em>e</em> <em>penali</em><em>z</em><em>e</em> <em>f</em><em>u</em><em>ll</em><em>y </em><em>iii</em><em>)</em><em>.</em><em> Accept inconstancy in the use of zero’s used as initial burette reading i.e o,0.0 0.00</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Accuracy (Tied to correct titre value …..</em></strong></li>
</ol>
<p><em>C</em><em>o</em><em>m</em><em>pa</em><em>r</em><em>e</em> <em>t</em><em>h</em><em>e</em> <em>c</em><em>a</em><em>nd</em><em>i</em><em>d</em><em>a</em><em>t</em><em>e</em><em>’</em><em>s</em> <em>t</em><em>i</em><em>t</em><em>r</em><em>e</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em><em>s</em> <em>wi</em><em>t</em><em>h</em> <em>t</em><em>h</em><em>e</em> <em>S</em><em>.</em><em>V</em> <em>a</em><em>n</em><em>d</em> <em>a</em><em>wa</em><em>r</em><em>d</em> <em>m</em><em>a</em><em>r</em><em>ks as follows i). If at least one is within +0.1 of S.V award …</em></p>
<p><em>ii). If none is within + 0.1 but at least one is within + 0.2 of S.V award iii). If no value is within +0.2 award 0 marks</em></p>
<p> ;</p>
<p><strong><em>Note:</em></strong></p>
<p><strong><em>If there is;</em></strong></p>
<ul>
<li><em>wrong arithmetic or subtraction in the table, then compare the worked </em></li>
</ul>
<p><em>Correct value and award accordingly.</em></p>
<ul>
<li><em>W</em><em>he</em><em>r</em><em>e</em> <em>t</em><em>he</em><em>r</em><em>e</em> <em>a</em><em>r</em><em>e</em> <em>t</em><em>w</em><em>o</em> <em>po</em><em>ss</em><em>i</em><em>bl</em><em>e</em> <em>S</em><em>.</em><em>V</em><em>’</em><em>s</em> <em>f</em><em>r</em><em>o</em><em>m</em> <em>t</em><em>h</em><em>e</em> <em>T</em><em>e</em><em>a</em><em>c</em><em>he</em><em>r</em><em>’</em><em>s</em> <em>r</em><em>e</em><em>s</em><em>u</em><em>l</em><em>t</em><em>s</em><em>,</em> <em>i</em><em>nd</em><em>i</em><em>c</em><em>a</em><em>t</em><em>e</em> <em>bo</em><em>t</em><em>h</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em><em>s</em> <em>o</em><em>n </em><em>the</em> <em>script</em> <em>and</em> <em>use</em> <em>one</em> <em>which</em> <em>is</em> <em>closer</em> <em>to</em> <em>the</em> <em>candidate</em> <em>value</em> <em>to</em> <em>award for accuracy and final answer</em></li>
<li><em>I</em><em>f</em> <em>n</em><em>o</em> <em>S</em><em>.</em><em>V</em> <em>i</em><em>s</em> <em>g</em><em>i</em><em>ve</em><em>n</em> <em>o</em><em>r</em> <em>c</em><em>a</em><em>n</em><em>’</em><em>t</em> <em>b</em><em>e</em> <em>wo</em><em>r</em><em>ked out from teacher’s value as per principles of averaging</em>
<ul>
<li><em>All candidates correct average tutors should be written down and close values </em><em>picked for averaging per session</em></li>
<li><em>If</em> <em>candidates average values are too varied ignore them and use KNEC value</em></li>
</ul>
</li>
</ul>
<p> ;</p>
<p><strong><em>C</em></strong><strong><em>o</em></strong><strong><em>m</em></strong><strong><em>p</em></strong><strong><em>a</em></strong><strong><em>r</em></strong><strong><em>e</em></strong> <strong><em>t</em></strong><strong><em>h</em></strong><strong><em>e</em></strong> <strong><em>c</em></strong><strong><em>a</em></strong><strong><em>n</em></strong><strong><em>d</em></strong><strong><em>i</em></strong><strong><em>d</em></strong><strong><em>a</em></strong><strong><em>t</em></strong><strong><em>e</em></strong><strong><em>’</em></strong><strong><em>s</em></strong> <strong><em>a</em></strong><strong><em>v</em></strong><strong><em>e</em></strong><strong><em>r</em></strong><strong><em>a</em></strong><strong><em>g</em></strong><strong><em>e</em></strong> <strong><em>t</em></strong><strong><em>i</em></strong><strong><em>t</em></strong><strong><em>r</em></strong><strong><em>e</em></strong> <strong><em>w</em></strong><strong><em>i</em></strong><strong><em>t</em></strong><strong><em>h</em></strong> <strong><em>S</em></strong><strong><em>.</em></strong><strong><em>V </em></strong><em>i). If within <sup>+</sup>0.1 of S.V award</em></p>
<p><em>ii). If not within <sup>+</sup> 0.1, but within + 0.2 of S.V award….. ½ mark iii). If not within + 0.2 of S.V award</em><em> </em><em>0 mark</em></p>
<p> ;</p>
<p><strong><em>Note;</em></strong></p>
<ul>
<li><em>If there are 2 possible average titre values use the one that is closer to the V and credit </em><em>accordingly</em></li>
<li><em>i</em><em>f</em> <em>w</em><em>r</em><em>o</em><em>n</em><em>g</em> <em>l</em><em>i</em><em>t</em><em>r</em><em>e</em> <em>v</em><em>a</em><em>l</em><em>u</em><em>e</em><em>s</em> <em>a</em><em>r</em><em>e</em> <em>a</em><em>ve</em><em>r</em><em>a</em><em>g</em><em>e</em><em>s</em> <em>b</em><em>y</em> <em>c</em><em>a</em><em>nd</em><em>i</em><em>d</em><em>a</em><em>t</em><em>e</em><em>s</em><em>,</em> <em>pic</em><em>k correct values (if any) average them and award accordingly</em></li>
</ul>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="9">
<table width="100%">
<tbody>
<tr>
<td><em>4</em></td>
</tr>
</tbody>
</table>
</td>
</tr>
</tbody>
</table>
<p><em>b). i). Moles of MnO <sup>&#8211;</sup> = <u>0.02 x AV.</u> Titre</em></p>
<p><em>1000</em></p>
<p><em>=Correct Ans.</em></p>
<ul>
<li><em>Moles of FE<sup>2+</sup> in 25cm<sup>3</sup></em></li>
</ul>
<p><em>Fe<sup>2+</sup> : Mn04- = 5: 1</em></p>
<p><em>= 5 x Ans b(i) above</em></p>
<p><em>= Correct Ans.</em></p>
<p> ;</p>
<ul>
<li><em>Moles of iron (i) ions in 250cm<sup>3</sup> = Ans b(ii) x 250cm<sup>3</sup></em></li>
</ul>
<p><em>25cm<sup>3</sup></em></p>
<p><em>Or Ans b(ii) x 10</em></p>
<p><em>= Correct Ans</em></p>
<p> ;</p>
<ol>
<li><strong><em>PRINCIPLES OF AVERAGING Conditions</em></strong>
<ul>
<li><em>If 3 consistent values averaged …..</em></li>
<li><em>If 3 titrations done, but only2 are consistent and averaged </em><em>iii). If only 2 titrations done, are consistent and averaged</em></li>
</ul>
</li>
</ol>
<ul>
<li><em>If 3 titrations done, but are inconsistent are averaged……</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>If 3 titrations done, and all can be averaged but only 2 are averaged </em><em>vi). If only 2 titrations are done, are inconsistent and averaged ….</em></li>
</ul>
<p> ;</p>
<p><strong><em>Penalties</em></strong></p>
<p><em>i). Penalise ½ mark for wrong arithmetic if the error is outside +2 units in the 2<sup>nd</sup> d.p ii). Penalise ½ mark for no working shown but correct answer is written</em></p>
<p><em>/stated</em></p>
<ul>
<li><em>If</em> <em>wrong</em> <em>answer</em> <em>is</em> <em>stated</em> <em>with</em> <em>no</em> <em>working</em></li>
<li><em>If</em> <em>wrong</em> <em>working</em> <em>shown</em> <em>with</em> <em>correct</em> <em>answer however accept</em></li>
</ul>
<p> ;</p>
<p><strong><em>Note:</em></strong></p>
<ul>
<li><em>Accept rounding off/truncation of answer to p e.g 17.666 = 17.67 or </em><em>17.66</em></li>
</ul>
<p><em>Otherwise penalize rounding off to 1 dp or to a whole number</em></p>
<ul>
<li><em>Accept answer if it works out exactly to 1 d.p or to a whole number</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>FINAL ACCURACY (Tied to correct average titre)</em></strong></li>
</ol>
<p><strong><em>Penalties/Conditions</em></strong></p>
<ul>
<li><em>Penalise ½ mark for wrong units used in part b(i)- b(ii) otherwise ignore omission </em><em>of units</em></li>
<li><em>Penalise ½ mark for wrong transfer in b(i) – b(ii) otherwise penalize fully for </em><em>strange figure in each case</em></li>
<li><em>Answer in b(i)- b(iii) should be at least unless it works out exactly to less than 4 </em><em>ps otherwise penalize ½ mark on the answer</em></li>
<li><em>Penalise ½ mark for wrong arithmetic in ans b(i) if the error on the answer is </em><em>outside 2 units in the 5<sup>th</sup> p</em></li>
<li><em>A</em><em>n</em><em>s</em><em>we</em><em>r</em> <em>i</em><em>n</em> <em>b(ii</em><em>)</em> <em>–</em> <em>b(iii</em><em>)</em> <em>m</em><em>u</em><em>s</em><em>t</em> <em>b</em><em>e</em> <em>a</em><em>s</em> <em>e</em><em>x</em><em>pec</em><em>t</em><em>e</em><em>d</em><em>,</em> <em>o</em><em>t</em><em>he</em><em>r</em><em>wi</em><em>s</em><em>e</em> <em>penali</em><em>z</em><em>e</em> <em>½</em> <em>m</em><em>a</em><em>r</em><em>k on the answer</em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Molar heat of displacement of CU<sup>2+</sup> ions </em></strong><em>CU<sup>2+</sup>: Fe = 1:1</em></li>
</ol>
<p><em>= <u>Ans a(iii)</u></em></p>
<p><em>b(iii)</em></p>
<p><em>= correct ans.</em></p>
<p> ;</p>
<p><strong><em>Penalties/conditions</em></strong></p>
<ul>
<li><em>Penalise ½ mark for wrong transfer of either a(iii) or b(iii) otherwise penalize fully for </em><em>strange figure</em></li>
<li><em>Penalise 1 mark for arithmetic error outside 200 units of expected answer if the answer </em><em>is in joules or outside 2 units if answer is in k</em></li>
<li><em>Penalise ½ mark on correct answer if either the correct sign (-ve) or correct unit is </em><em>missing or both are wrong/missing</em></li>
<li><em>Penalise fully for unrealistic answer e beyond 200 KJ/mole or 200,000 J/Mole</em></li>
</ul>
<p> ;</p>
<p><strong><em>Note:</em></strong></p>
<p><em>F</em><em>o</em><em>r</em> <em>c</em><em>o</em><em>n</em><em>t</em><em>i</em><em>n</em><em>u</em><em>e</em><em>d</em> <em>wo</em><em>r</em><em>king, mark only the 1<sup>st</sup> correct areas.</em></p>
<p> ;</p>
<ol>
<li><strong><em>Procedure </em></strong><em>a). i).</em></li>
</ol>
<p> ;</p>
<ul>
<li><em>I). extrapolated graph</em></li>
</ul>
<p><em>showing/without</em> <em>showing 1 mark II). from extrapolated graph – wrongly stated but shown on the</em></p>
<p><em>graph ½ mark</em></p>
<ul>
<li><em>DH = MCDT</em></li>
</ul>
<p> ;</p>
<p><em>= 50 x 4.2 x DT</em></p>
<p><em>= Correct answer Joules J.j Or = <u>50 x 4.2 x D.J</u></em></p>
<p><em>1000</em></p>
<p><em>= Correct answer (Kilo joules K.J)</em></p>
<p><em>-Ignore formula for working DH. Given must be correct otherwise penalize ½ </em><em>mark for wrong formula.</em></p>
<p><em>&#8211; Penalise ½ mark for wrong units or omission</em></p>
<p><em>-Ignore</em> <em>if</em> <em>no</em> <em>sign</em> <em>is</em> <em>given</em> <em>otherwise</em> <em>if</em> <em>no</em> <em>sign</em> <em>is</em> <em>given</em> <em>otherwise</em> <em>penalize ½ markf or (+) sign</em></p>
<p><em>1 ½ mark</em></p>
<ol start="2">
<li><strong><em>Procedure </em></strong></li>
</ol>
<table>
<tbody>
<tr>
<td width="338"> ;</td>
<td width="143"><em>I</em></td>
<td width="128"><em>II</em></td>
<td width="122"><em>III</em></td>
</tr>
<tr>
<td width="338"><em>Final burette reading</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
<tr>
<td width="338"><em>Initial burette reading</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
<tr>
<td width="338"><em>Volume of solution C used (cm<sup>3</sup>)</em></td>
<td width="143"> ;</td>
<td width="128"> ;</td>
<td width="122"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><strong> </strong></p>
<p><em>a). 1 + 11 + 1</em></p>
<p><em>3 </em><em>= ans</em></p>
<p><em>4</em> <em>marks</em></p>
<p> ;</p>
<p> ;</p>
<p><em>1 mark</em></p>
<p> ;</p>
<p><em>i).</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-Colourless</em></p>
<p><em>-Odourless gas produced</em></p>
<p><em>-Gas</em> <em>extinguishes</em> <em>a</em> <em>burning</em> <em>splint</em></p>
<p><em>-White residue or solid turns yellow when heated and turns white on </em><em>cooling</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-CO</em><em>3 2- </em><em>(Extinguishes burning splint)</em></p>
<p><em>-Zn<sup>2+/</sup>ZnO formed (turned to white on </em><em>cooling )</em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p><em>Award ½ mark upto a maximum of 1 mark</em></p>
<p><em>Penalise ½ mark for each contradictory low in each case Reject; ZnO present.</em></p>
<p><em>ii).</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-Colourless</em></p>
<p><em>-Odourless gas produced</em></p>
<p><em>-Gas</em> <em>extinguishes</em> <em>a</em> <em>burning</em> <em>splint</em></p>
<p><em>-White residue /solid turns yellow when heated and turns white on </em><em>cooking</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-CO</em><em>3 2- </em><em>present</em></p>
<p><em>Penalize fully for any contradictory ion </em><em>Zn<sup>2+</sup> present</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Reject ; Hissing /Fizzing</em></p>
<p><em>iii).</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-White ppt</em></p>
<p><em>-soluble in excess (1 mark)</em></td>
<td width="302"><em>-Zn<sup>2+/</sup>Zno formed (turned to white )</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Penalise fully for contradictory ions</em></p>
<p> ;</p>
<p> ;</p>
<p><em>b). i).</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-White ppt</em></p>
<p><em>-ignore</em> <em>if</em> <em>ppt</em> <em>is</em> <em>insoluble</em> <em>in</em> <em>excess</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>&#8211;</em><em>A</em><em>l</em><em><sup>3</sup></em><em><sup>+</sup></em><em>,</em> <em>P</em><em>b<sup>2</sup></em><em><sup>+</sup></em><em><sup>,</sup></em> <em>M</em><em>g</em><em><sup>2</sup></em><em><sup>+</sup></em> <em>p</em><em>r</em><em>e</em><em>s</em><em>e</em><em>n</em><em>t </em><em>Note</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li><em> a).</em></li>
</ol>
<p> ;</p>
<p><em>ii).</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>iii).</em></p>
<p><em>Penalize fully for ppt dissolves</em></p>
<p> ;</p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>&#8211; No effervescence</em></p>
<p><em>-No white ppt</em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-CO <sup>2-</sup>, SO <sup>2-</sup> absent</em></p>
<p><em>3 3</em></p>
<p><em>(both ½ mark)</em></p>
<p><em>-Al<sup>3+</sup>, Mg<sup>2+</sup> present</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Accept : No ppt</em></p>
<p><em>½ mark – colourless solution formed</em></p>
<p><em>&#8211; Solution remains colourless</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-White ppt formed</em></p>
<p><em>-penalise fully if ppt dissolves</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-Pb<sup>2+</sup></em> <em>ions</em> <em>absent penalized ½ mark for any contradictory ion</em></p>
<p><em>SO4<sup>2-</sup></em> <em>present</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Penalise fully for any contradictions ions </em><em>Accept</em> <em>if</em> <em>ions</em> <em>are written in words</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>&#8211; melts and burns with a sooty/luminous / yellow smoky flame</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-‘C=C’/ C=C-</em></p>
<p><em>-Organic compound with high C;L</em></p>
<p><em>-Long chain organic compound</em></p>
<p><em>&#8211; Unsaturated organic</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>b). </em><em>i).</em></p>
<p><em>Melts on its own for ½ mark Carbon – carbon dissolves C=C/C=C</em></p>
<p><em>Alkalines/alkynes</em></p>
<p><em>Long chain hydrocarbon</em></p>
<p> ;</p>
<p><strong><em><u>Note:</u></em></strong></p>
<p><em>Penalise fully for any contradictory ion</em></p>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-KMNO</em><em>4</em><em>/H<sup>+</sup> is not decolouress colour of KMN0</em><em>4</em><em>/H<sup>+</sup> remains purple/purple </em><em>colour of KMNO</em><em>4</em><em>/H<sup>+</sup> persists or </em><em>remains the same</em></p>
<p><em>(1 mark)</em></td>
<td width="302"><em>-H<sup>+</sup>/H</em><em>3</em><em>O+ or 4 – COOH or carboxyli </em><em>growing</em> <em>in</em> <em>words/solutions</em> <em>in acidic</em></p>
<p><em> </em></p>
<p><em>1 mark</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Saturated</em> <em>organic</em> <em>compound</em> <em>present</em> <em>for ½ mark</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-Effervescence /bubbles /fizzing </em><em>(1 mark)</em></td>
<td width="302"><em>&#8211; H<sup>+</sup>/H</em><em>3</em><em>O<sup>+</sup> or 4 –COOH or carboxyli </em><em>growing</em> <em>in</em> <em>words</em> <em>/solution is acidic</em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p><em>Accept : Colourless gas for ½ mark Reject : Hissing/fizzling</em></p>
<p><em>c).</em></p>
<table>
<tbody>
<tr>
<td width="293"><em>Observations</em></td>
<td width="302"><em>Inferences</em></td>
</tr>
<tr>
<td width="293"><em>-Dip the p H /universal paper into the </em><em>solution from (b) above</em></p>
<p><em>-match the colour obtained with the </em><em>p H chart and not the p H= 1 or 2</em></p>
<p><em>(1mark)</em></td>
<td width="302"><em>-Solution is strongly acidic</em></p>
<p><em> </em></p>
<p><em> </em></p>
<p><em>(1 mark)</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>Reject: p H range ( p H = 1 -2)</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<h2>CONFIDENTIAL AND PREPARATION INSTRUCTIONS TO SCHOOLS</h2>
<p><strong><em>October &#8211; November 1989 Instructions to Schools.</em></strong></p>
<p> ;</p>
<p><em>This is information that enables the Head of the school and the teacher in charge of Chemistry to make adequate preparations for Chemistry Practical Examination.</em></p>
<p> ;</p>
<p><em>In addition to the fittings and substances ordinarily contained in a chemical laboratory, the following </em><em>should be provided.</em></p>
<p> ;</p>
<p><strong><em>Requirements per Candidate</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Each candidate will require the following:</em></strong></p>
<ul>
<li><em>About 75cm<sup>3</sup> of solution <strong>W9</strong></em></li>
<li><em>About 150cm<sup>3</sup> of solution <strong>W11</strong></em> <strong><em>(oxallic acid)</em></strong></li>
<li><em>About 1g of solid <strong>Y</strong></em></li>
<li><em>About 10cm of metal <strong>M</strong></em> <strong><em>(magnesium ribbon)</em></strong></li>
<li><em>1 pipette of 0cm<sup>3</sup></em></li>
<li><em>3 conical flasks</em></li>
<li><em>1</em> <em>burette</em></li>
<li><em>1 measuring cylinder of 100cm<sup>3</sup></em></li>
<li><em>1 beaker of 250cm<sup>3</sup></em></li>
<li><em>Tissue paper</em></li>
<li><em>1 boiling tube</em></li>
<li><em>1</em> <em>thermometer</em> <em>(accuracy</em> <em>5<sup>0</sup>C)</em></li>
<li><em>1 ruler</em></li>
<li><em>1 spatula</em></li>
<li><em>5 test-tubes</em></li>
<li><em>A sharp blade or pair of scissors</em></li>
<li><em>A</em> <em>small</em> <em>funnel</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to</em></strong></p>
<ul>
<li><em>250cm<sup>3</sup> of distilled water</em></li>
<li><em>Dilute hydrochloric acid</em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>Dilute sodium hydroxide</em></li>
<li><em>Aqueous ammonia</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution W9 is made by dissolving 90cm<sup>3</sup> of concentrated hydrochloric acid in distilled water and making it to one litre of This solution MUST be supplied in a burette placed at a central position where it should be accessible to 5 to 10 candidates.</em></li>
<li><em>Solution W11 is made by dissolving 30g of solid W11 in distilled water and making it up to one litre of solution.</em></li>
</ol>
<ul>
<li><em>Solution W12 is made by dissolving 3.20g of sodium hydroxide pellets in distilled water and making it up to one litre of </em></li>
</ul>
<ol>
<li><em>Metal M should be cleaned with sand-paper the day before the </em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 1990. </em></strong><strong><em>Requirements for Candidates</em></strong></p>
<p><em>I</em><em>n</em> <em>a</em><em>dd</em><em>i</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>t</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>f</em><em>i</em><em>tt</em><em>i</em><em>n</em><em>g</em><em>s</em><em>,</em> <em>s</em><em>u</em><em>b</em><em>s</em><em>t</em><em>a</em><em>n</em><em>c</em><em>e</em><em>s</em> <em>a</em><em>n</em><em>d</em> <em>a</em><em>ppa</em><em>r</em><em>a</em><em>t</em><em>u</em><em>s</em> <em>o</em><em>r</em><em>d</em><em>i</em><em>n</em><em>a</em><em>r</em><em>i</em><em>l</em><em>y</em> <em>f</em><em>o</em><em>u</em><em>n</em><em>d</em> <em>i</em><em>n</em> <em>a</em> <em>c</em><em>he</em><em>m</em><em>i</em><em>s</em><em>t</em><em>r</em><em>y</em> <em>l</em><em>a</em><em>bo</em><em>r</em><em>a</em><em>t</em><em>o</em><em>r</em><em>y</em> <em>e</em><em>a</em><em>c</em><em>h </em><em>candidate will require the following;</em></p>
<p> ;</p>
<ul>
<li><em>Between</em> <em>0g</em> <em>and</em> <em>1.5g</em> <em>of</em> <em>solid D,</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>A</em><em>bou</em><em>t</em><em> 250cm<sup>3</sup> of solution S1, (Sodium hydroxide)</em></li>
<li><em>A</em><em>bou</em><em>t</em> <em>150</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>S</em><em>1</em><em>,</em></li>
<li><em>About 0g of solid Q</em></li>
<li><em>About 400cm<sup>3</sup> of distilled water</em></li>
<li><em>One burette</em></li>
<li><em>One</em> <em>25cm<sup>3</sup></em> <em>of</em> <em>pipette</em></li>
<li><em>One</em> <em>10cm<sup>3</sup></em> <em>pipette</em></li>
<li><em>One 100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>One filter funnel</em></li>
<li><em>One</em> <em>filter</em> <em>paper</em></li>
<li><em>conical flasks (250cm<sup>3</sup>)</em></li>
<li><em>One thermometer (0-10<sup>0</sup>C – 0-110<sup>0</sup>C)</em></li>
<li><em>One crucible or crucible lid or a metallic spatula</em></li>
<li><em>One spatula</em></li>
<li><em>One test tube holder</em></li>
<li><em>test</em> <em>tubes</em></li>
<li><em>Two</em> <em>boiling</em> <em>tubes</em></li>
<li><em>One dropper</em></li>
</ul>
<p> ;</p>
<p><strong><em><u>Access to:</u></em></strong></p>
<ul>
<li><em>Phenolphthalein indicator</em></li>
<li><em>pH paper (range 1-14)</em></li>
<li><em>Solid sodium hydrogen carbonate</em></li>
<li><em>1% potassium manganate (VII) solution</em></li>
<li><em>1%</em> <em>bromine</em> <em>water</em></li>
<li><em>Burner</em></li>
<li><em>Concentrated sulphuric acid supplied with a dropper pipette</em></li>
<li><em>About 6cm<sup>3</sup> of ethanol</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ul>
<li><em>Solids D and Q will be provided by the Kenya National Examinations </em></li>
<li><em>Preparations</em> <em>of</em> <em>solution</em> <em>S1:</em>
<ul>
<li><em>Dissolves 0g of sodium hydroxide in distilled water and make it up to one litre of solution</em></li>
<li><em>Take 200cm<sup>3</sup> of the sodium hydroxide solution prepared in (i) above and dilute with distilled water to make up one litre of solution (SI)</em></li>
</ul>
</li>
<li><em>Preparation of solution S2:</em></li>
</ul>
<ol>
<li><em>I) Dissolve 56cm<sup>3</sup> of concentrated sulphuric acid in about 500cm<sup>3</sup> of distilled </em></li>
</ol>
<p><em>II). Take 10cm<sup>3</sup> of the sulphuric acid solution prepared in (i) above and dilute it by adding distilled water to make it up to one litre of solution (S2).</em></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 1992 </em></strong><strong><em>Requirements for Candidates</em></strong></p>
<p><strong><em>In addition to fittings and apparatus found in a chemistry laboratory, each candidate will require:</em></strong></p>
<ul>
<li><em>60</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em><em>2</em><em>,</em></li>
<li><em>100cm<sup>3</sup> of solution C3</em></li>
<li><em>150cm<sup>3</sup> of solution C5</em></li>
<li><em>150cm<sup>3</sup> of solution C6</em></li>
<li><em>About 1g of solid C7</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>One, 50cm<sup>3</sup> burette</em></li>
<li><em>One, 100cm<sup>3</sup> beaker</em></li>
<li><em>One, 25cm<sup>3</sup> (or 20cm<sup>3</sup> ) pipette,</em></li>
<li><em>One,</em> <em>10cm<sup>3</sup></em> <em>measuring</em> <em>cylinder</em></li>
<li><em>Three, 250cm<sup>3</sup> conical flasks</em></li>
<li><em>S</em><em>eve</em><em>n</em><em>,</em> <em>c</em><em>l</em><em>e</em><em>a</em><em>n</em> <em>d</em><em>r</em><em>y</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>s</em> <em>place</em><em>d</em> <em>i</em><em>n</em> <em>a</em> <em>r</em><em>a</em><em>c</em><em>k</em></li>
<li><em>O</em><em>n</em><em>e</em><em>,</em> <em>s</em><em>t</em><em>o</em><em>p watch / stop clock,</em></li>
<li><em>One, boiling tube</em></li>
<li><em>One, </em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<ul>
<li><em>M</em><em>e</em><em>t</em><em>h</em><em>y</em><em>l</em> <em>o</em><em>r</em><em>a</em><em>n</em><em>g</em><em>e</em> <em>i</em><em>nd</em><em>i</em><em>c</em><em>a</em><em>t</em><em>o</em><em>r</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em></li>
<li><em>5M lead nitrate solution</em></li>
<li><em>5M barium chloride solution</em></li>
<li><em>About 10cm<sup>3</sup> of solution C4</em></li>
<li><em>Dilute sulphuric acid</em></li>
<li><em>D</em><em>i</em><em>l</em><em>u</em><em>t</em><em>e</em> <em>s</em><em>o</em><em>d</em><em>i</em><em>u</em><em>m</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>x</em><em>i</em><em>d</em><em>e</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em><em>,</em></li>
<li><em>Source of heat (Bunsen burner)</em></li>
<li><em>300cm<sup>3</sup> of distilled water</em></li>
<li><em>Note:</em> <em>all the solutions should be freshly prepared and supplied accompanied by </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution C2 is prepared by dissolving 2g of solid C2 in distilled water and making it up to one litre</em></li>
<li><em>Solution C3 is prepared by dissolving 0.40g of solid C3 in about 200cm<sup>3</sup> of distilled water, adding 20cm<sup>3</sup> of 1M sulphuric acid, shaking well and making it up to one litre with distilled water.</em></li>
</ol>
<ul>
<li><em>Solution C4 is prepared by placing 0g of solid C4 in 100cm<sup>3</sup> beaker, adding 2cm<sup>3</sup> of distilled water to make a paste and pouring the paste into 100cm<sup>3</sup> of boiling distilled water, boiling the mixture for about one minute and allowing it to cool. Solution C4 is to be prepared on the morning of the examination.</em></li>
</ul>
<ol>
<li><em>Solution C5 is peppered by adding 10cm<sup>3</sup> of concentrated hydrochloric acid (specific gravity of 18 or 1.9) in 500cm<sup>3</sup> of distilled water and making it up to one litre.</em></li>
<li><em>Solution C6 is prepared by dissolving 19.2 of solid C6 in about 500cm<sup>3</sup> of warm distilled water, cooling the solution, transferring it into a volumetric flask and making it up to one litre with distilled </em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 1993 </em></strong><strong><em>Requirements</em></strong> <strong><em>for</em></strong> <strong><em>Candidates</em></strong></p>
<p><em>I</em><em>n</em> <em>a</em><em>dd</em><em>i</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>t</em><em>o</em> <em>t</em><em>h</em><em>e</em> <em>e</em><em>q</em><em>u</em><em>i</em><em>p</em><em>m</em><em>e</em><em>n</em><em>t</em><em>s</em><em>,</em> <em>a</em><em>ppa</em><em>r</em><em>a</em><em>t</em><em>u</em><em>s</em> <em>a</em><em>n</em><em>d</em> <em>c</em><em>he</em><em>m</em><em>i</em><em>c</em><em>a</em><em>l</em><em>s</em> <em>f</em><em>o</em><em>u</em><em>n</em><em>d</em> <em>i</em><em>n</em> <em>a</em><em>n</em> <em>o</em><em>r</em><em>d</em><em>i</em><em>n</em><em>a</em><em>r</em><em>y</em> <em>c</em><em>he</em><em>m</em><em>i</em><em>s</em><em>t</em><em>r</em><em>y</em> <em>l</em><em>a</em><em>bo</em><em>r</em><em>a</em><em>t</em><em>o</em><em>r</em><em>y</em><em>,</em> <em>e</em><em>a</em><em>c</em><em>h </em><em>candidate will require the following;</em></p>
<ul>
<li><em>75cm<sup>3</sup> of solution A</em></li>
<li><em>0cm<sup>3</sup> of solid B</em></li>
<li><em>200cm<sup>3</sup> of solution C</em></li>
<li><em>About 1g of solid F</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>One, 50cm<sup>3</sup> burette</em></li>
<li><em>One</em> <em>25cm<sup>3</sup></em> <em>pipette</em></li>
<li><em>Five 25cm<sup>3</sup> conical flasks</em></li>
<li><em>One, 100 cm<sup>3</sup> measuring cylinder</em></li>
<li><em>One, filter funnel</em></li>
<li><em>S</em><em>i</em><em>x</em><em>,</em> <em>t</em><em>e</em><em>s</em><em>t</em> <em>t</em><em>u</em><em>be</em><em>s</em></li>
<li><em>One, spatula</em></li>
<li><em>One boiling tube</em></li>
<li><em>One filter paper cut into small strips of about 1cm and at least 5cm long </em><strong><em>Access to:</em></strong></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>About 500cm<sup>3</sup> of distilled water</em></li>
<li><em>05M</em> <em>iodine</em> <em>solution</em></li>
<li><em>2</em> <em>M</em> <em>hydrochloric</em> <em>acid solution</em></li>
<li><em>2M sodium hydroxide solution</em></li>
<li><em>24M</em> <em>barium</em> <em>dichromate</em> <em>solution</em></li>
<li><em>A wall clock placed in a position visible for all candidates</em></li>
<li><em>Two labels</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ul>
<li><em>Solution</em> <em>A</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>40g</em> <em>of</em> <em>sodium</em> <em>hydroxide</em> <em>pellets</em> <em>in about 500cm<sup>3</sup> of distilled water then making it up to one litre of solution</em></li>
<li><em>Solution</em> <em>C</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>7g</em> <em>of</em> <em>solid</em> <em>C</em> <em>in</em> <em>about</em> <em>500cm<sup>3</sup></em> <em>of</em> <em>distilled</em> <em>water</em> <em>and</em> <em>making it up to one litre of solution</em></li>
<li><em>The</em> <em>0g</em> <em>solid</em> <em>B</em> <em>should</em> <em>be</em> <em>weighed</em> <em>accurately</em> <em>for</em> <em>each</em> <em>candidate</em> <em>and supplied in a dry weighing bottle or test tube or any other small dry container</em></li>
<li><em>05M iodine solution is prepared by dissolving 20g of potassium iodide crystals in 600cm<sup>3</sup> of water then adding 12.7g of iodide crystals dissolving and making it up to one litre solution</em></li>
</ul>
<p> ;</p>
<p><strong><em>October / November 1994 </em></strong><strong><em>Requirements for Candidates.</em></strong></p>
<p><em>In addition to fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<ul>
<li><em>200cm<sup>3</sup> of solution D</em></li>
<li><em>150cm<sup>3</sup> of solution E</em></li>
<li><em>50cm<sup>3</sup> of solution F</em></li>
<li><em>50cm<sup>3</sup> of solution G</em></li>
<li><em>About 5g of solid H</em></li>
<li><em>One, 50cm<sup>3</sup> burette</em></li>
<li><em>One, 100cm<sup>3</sup> beaker</em></li>
<li><em>One,</em> <em>10cm<sup>3</sup></em> <em>measuring</em> <em>cylinder</em></li>
<li><em>One 100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>One 25cm<sup>3</sup> (or 20cm<sup>3</sup> ) pipette</em></li>
<li><em>Three, 250cm<sup>3</sup> conical flasks</em></li>
<li><em>E</em><em>i</em><em>g</em><em>h</em><em>t</em><em>,</em> <em>c</em><em>l</em><em>e</em><em>a</em><em>n</em> <em>d</em><em>r</em><em>y</em> <em>t</em><em>e</em><em>s</em><em>t</em><em>&#8211;</em><em>t</em><em>u</em><em>be</em><em>s</em><em>.</em></li>
<li><em>One</em> <em>thermometer</em> <em>(-10<sup>0</sup>C</em> <em>to</em> <em>110<sup>0</sup>C</em></li>
<li><em>One metallic spatula</em></li>
<li><em>About 5g of solids &#8211; Sodium chloride</em>
<ul>
<li><em>Potassium chloride</em></li>
<li><em>Calcium chloride</em></li>
</ul>
</li>
<li><em>One boiling tube</em></li>
<li><em>Stirring rod</em></li>
<li><em>About 1g of steel wool <strong>Access </strong></em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>2M sodium </em></li>
<li><em>2M aqueous ammonia</em></li>
<li><em>2M sodium chloride</em></li>
<li><em>Bunsen burner (heat source)</em></li>
<li><em>Distilled</em> <em>water</em></li>
<li><em>Each of the above solutions should be supplied with a </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol start="8">
<li><em>Solution D is prepared by dissolving 0g of sodium hydroxide pellets in distilled water and making it up to one litre.</em></li>
<li><em>Solution E is prepared by dissolving 19.2g of solid E in distilled water and making it up to one litre.</em></li>
</ol>
<ul>
<li><em>Solution F is prepared by dissolving 0g of sodium hydroxide pellets in distilled water and top it up to one litre.</em></li>
</ul>
<ol start="79">
<li><em>Solution G is prepared by dissolving 79.4g of solid G in distilled water and making it up to one litre.</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 1995</em></strong></p>
<p> ;</p>
<p><strong><em>Requirements for Candidates</em></strong></p>
<p><strong> </strong></p>
<p><em>In addition to the equipment, apparatus and chemicals found in an ordinary chemistry laboratory, each </em><em>candidate will require the following;</em></p>
<ul>
<li><em>2</em><em>.</em><em>0</em><em>g</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>J</em><em>,</em> <em>weighe</em><em>d</em> <em>a</em><em>cc</em><em>u</em><em>r</em><em>a</em><em>t</em><em>e</em><em>l</em><em>y</em></li>
<li><em>1</em><em>.</em><em>0</em><em>g</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>K</em><em>,</em> <em>weighe</em><em>d</em> <em>a</em><em>cc</em><em>u</em><em>r</em><em>a</em><em>t</em><em>e</em><em>l</em><em>y</em></li>
<li><em>About 2g of solid L</em></li>
<li><em>About 8g of solid N</em></li>
<li><em>100cm<sup>3</sup> of 0M hydrochloric acid</em></li>
<li><em>One, 50cm<sup>3</sup> burette</em></li>
<li><em>One, thermometer</em></li>
<li><em>One,</em> <em>stopwatch/stopclock/watch</em> <em>with a second hand</em></li>
<li><em>One,</em> <em>100cm<sup>3</sup></em> <em>beaker</em></li>
<li><em>Two pieces of aluminium foil (2cm<sup>3</sup> each)</em></li>
<li><em>Six test-tubes</em></li>
<li><em>Two wooden splints</em></li>
<li><em>Three blue and three red litmus papers</em></li>
<li><em>One metallic spatula</em></li>
<li><em>One boiling tube</em></li>
<li><em>One 10cm<sup>3</sup> measuring cylinder</em></li>
<li><em>One glass rod</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<ul>
<li><em>About 500cm<sup>3</sup> of distilled water</em></li>
<li><em>0M hydrochloric acid (labeled as dilute)</em></li>
<li><em>0M sodium hydroxide (labeled as dilute)</em></li>
<li><em>Bunsen burner</em></li>
<li><em>About 50cm<sup>3</sup> of 1M lead nitrate solution</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<p><em>The</em> <em>2.0M</em> <em>hydrochloric</em> <em>acid</em> <em>should</em> <em>be</em> <em>prepared</em> <em>accurately by adding 175cm<sup>3</sup> of concentrated hydrochloric acid to about 700cm<sup>3</sup> of distilled water. Shake well and make it up to the one litre</em></p>
<p> ;</p>
<p><strong><em>October /November 1996 </em></strong><strong><em>Candidates requirements</em></strong></p>
<p><em>In addition to the apparatus and chemicals found in an ordinary Chemistry laboratory, each candidate will </em><em>require the following:</em></p>
<ul>
<li><em>150cm<sup>3</sup> of solution A</em></li>
<li><em>100cm<sup>3</sup> of solution B</em></li>
<li><em>100cm<sup>3</sup> of solution C</em></li>
<li><em>One 50cm<sup>3</sup> burette</em></li>
<li><em>One</em> <em>25cm<sup>3</sup></em> <em>pipette</em></li>
<li><em>One</em> <em>thermometer</em> <em>(0<sup>0</sup>C to 100<sup>0</sup>C)</em></li>
<li><em>One filter funnel</em></li>
<li><em>About 5g of solid D</em></li>
<li><em>Six clean dry test-tubes on a test-tube rack</em></li>
<li><em>Two</em> <em>boiling</em> <em>tubes</em></li>
<li><em>One metallic spatula</em></li>
<li><em>Two filter papers</em></li>
<li><em>Wooden splint</em></li>
<li><em>Four red and four blue litmus papers</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>One teat pipette dropper</em></li>
<li><em>About 5g of solid E</em></li>
<li><em>About half a spatula full of solid sodium hydrogen carbonate</em></li>
<li><em>One conical flask</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to</em></strong></p>
<ul>
<li><em>Bunsen burner</em></li>
<li><em>About 500cm<sup>3</sup> of distilled water</em></li>
<li><em>20</em> <em>volume</em> <em>hydrogen</em> <em>peroxide</em></li>
<li><em>2M sodium hydroxide</em></li>
<li><em>6M hydrochloric acid</em></li>
<li><em>Concentrated sulphuric acid</em></li>
<li><em>Ethanol</em></li>
</ul>
<p><strong><em><u>NB:</u></em></strong><strong><em> </em></strong><em>Each of the above reagents should be supplied with a dropper.</em></p>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ul>
<li><em>Solution A is prepared by dissolving 3.16g of solid A in 400cm<sup>3</sup> of 2M sulphuric acid and making it up to one litre of solution with distilled </em></li>
<li><em>Solution B is prepared by dissolving 5g of solid B in 200cm<sup>3</sup> of 2M sulphuric acid and making it up to one litre of solution with distilled water. This solution should be prepared in the morning of the examination.</em></li>
<li><em>Solution C is prepared by dissolving 0g of solid C in 600cm<sup>3</sup> of distilled water and making it up </em><em>to one litre of solution with the distilled water</em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 1997 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require. </em><strong><em>A</em></strong></p>
<ul>
<li><em>120cm<sup>3</sup></em> <em>of</em> <em>solution</em> <em>F,</em> <em>sulphuric</em></li>
</ul>
<ul>
<li><em>100cm<sup>3</sup> of solution G, 5M sodium hydroxide</em></li>
<li><em>2g of solid H weighed accurately – mg</em></li>
<li><em>One</em> <em>50cm<sup>3</sup></em> <em>burette</em></li>
<li><em>One 0cm<sup>3</sup> pipette</em></li>
<li><em>One 100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>One 100cm<sup>3</sup> beaker</em></li>
<li><em>Two conical flasks</em></li>
<li><em>One thermometer 0<sup>0</sup>C – 110<sup>0</sup>C</em></li>
<li><em>One 250cm<sup>3</sup> beaker</em></li>
<li><em>One label</em></li>
<li><em>One stopwatch/ stopclock or a watch with seconds hand</em></li>
<li><em>About 5g of solid L</em></li>
<li><em>6 clean dry test-tubes</em></li>
<li><em>One wooden splint</em></li>
<li><em>One filter funnel</em></li>
<li><em>One spatula</em></li>
<li><em>Two blue and two red litmus papers</em></li>
<li><em>About 5g of solid M</em></li>
<li><em>About 5g of sodium carbonate</em></li>
<li><em>One boiling tube</em></li>
<li><em>One test-tube holder</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>One filter </em></li>
</ul>
<p> ;</p>
<ol>
<li><em>Access </em>
<ul>
<li><em>Concentrated nitric acid</em></li>
<li><em>2M sulphuric acid</em></li>
<li><em>2M NaOH</em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>2M</em> <em>aqueous</em> <em>ammonia</em></li>
<li><em>1% Bromine water</em></li>
<li><em>Acidified</em> <em>potassium permanganate</em></li>
<li><em>Distilled water in a wash bottle</em></li>
<li><em>Bunsen burner</em></li>
</ul>
</li>
</ol>
<p><em>NB/ Each of the solutions in Bottle should be supplied with a dropper.</em></p>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol start="27">
<li><em>Solution F is prepared by accurately adding 8cm<sup>3</sup> of con. H</em><em>2</em><em>SO</em><em>4 </em><em>(s.g. 1.84) to about 400cm<sup>3</sup> of distilled H</em><em>2</em><em>O then making it to one litre of solution.</em></li>
<li><em>Solution</em><em>G</em><em> </em><em>is</em><em> </em><em>prepared</em><em> </em><em>by</em><em> </em><em>dissolving</em><em> </em><em>0g of NaOH pellets in 600cm<sup>3</sup> of distilled H</em><em>2</em><em>O then </em><em>making it to one litre of solution</em></li>
<li><em>Acidified potassium permanganate is prepared by dissolving 6g of solid KMnO</em><em>4 </em><em>in 400cm<sup>3</sup> of 1M H</em><em>2</em><em>SO</em><em>4 </em><em>acid and making it to one litre of solution.</em></li>
<li><em>1%</em><em>Bromine</em><em> </em><em>water</em><em> </em><em>is</em><em> </em><em>prepared</em><em> </em><em>by</em><em> </em><em>adding</em><em> </em><em>1cm<sup>3</sup></em><em> </em><em>(CARE)</em><em> </em><em>of</em><em> </em><em>liquid</em><em> </em><em>Bromine</em><em> </em><em>to 100cm<sup>3</sup> of distilled H</em><em>2</em><em>O </em><em>in a fume cupboard and shaking thoroughly</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 1998 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<ul>
<li><em>250</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>M</em><em>.</em></li>
<li><em>150cm<sup>3</sup> of sodium hydroxide, solution N</em></li>
<li><em>50g of solid P weighed accurately</em></li>
<li><em>Burette 0 – 50cm<sup>3</sup></em></li>
<li><em>Pipette 25cm<sup>3</sup></em></li>
</ul>
<p> ;</p>
<p><strong><em>Means of labeling.</em></strong></p>
<ul>
<li><em>100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>250cm<sup>3</sup> beaker</em></li>
<li><em>Two conical flasks</em></li>
<li><em>About 3g of solid L</em></li>
<li><em>Six dry test-tubes</em></li>
<li><em>2</em> <em>red</em> <em>and</em> <em>2</em> <em>blue</em> <em>litmus</em> <em>papers</em></li>
<li><em>2</em> <em>boiling</em> <em>tubes</em></li>
<li><em>One wooden splint</em></li>
<li><em>Filter paper</em></li>
<li><em>Filter funnel</em></li>
<li><em>About 2g of Na</em><em>2</em><em>CO</em><em>3</em></li>
<li><em>about 3g of solid S</em></li>
<li><em>A spatula</em></li>
<li><em>A</em> <em>test-tube</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<p> ;</p>
<ul>
<li><em>10cm<sup>3</sup> measuring cylinder</em></li>
<li><em>Distilled</em> <em>water</em></li>
<li><em>Universal indicator solution supplied with a dropper</em></li>
<li><em>pH</em> <em>chart</em></li>
<li><em>2M hydrochloric acid supplied with a dropper</em></li>
<li><em>2M aqueous ammonia supplied with a dropper</em></li>
<li><em>Wall clock</em></li>
<li><em>2M aqueous sodium hydroxide supplied with a dropper</em></li>
<li><em>2M barium chloride supplied with a dropper</em></li>
<li><em>Bunsen burner</em></li>
<li><em>1M lead(II) nitrate solution supplied with a dropper</em></li>
<li><em>Screened methyl orange indicator supplied with a </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution</em> <em>M is prepared by adding 0cm<sup>3</sup> (S.G = 1 = 1.18) of concentrated hydrochloric acid into 600cm<sup>3</sup> of distilled water contained in a one litre volumetric flask and diluting to one litre of solution.</em></li>
<li><em>Solution</em> <em>N</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>80g</em> <em>of</em> <em>sodium</em> <em>hydroxide</em> <em>in</em> <em>600cm<sup>3</sup> of distilled water contained in a one litre volumetric flask and diluting to one litre of solution.</em></li>
<li><em>Screened</em> <em>methyl</em> <em>orange</em> <em>is</em> <em>prepared</em> <em>by dissolving 10g of solid R in 100cm<sup>3</sup> of distilled water and labelled screened methyl orange indicator.</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 1999 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require the </em><em>following.</em></p>
<p> ;</p>
<ul>
<li><em>One burette 0 – 50cm<sup>3</sup></em></li>
<li><em>One</em> <em>pipette</em> <em>25cm<sup>3</sup></em></li>
<li><em>About 100cm<sup>3</sup> of solution E</em></li>
<li><em>About 120cm<sup>3</sup> of solution F</em></li>
<li><em>Two conical flasks ) 250cm<sup>3</sup></em></li>
<li><em>8 clean dry test-tubes</em></li>
<li><em>About</em> <em>4g</em> <em>of</em> <em>solid</em> <em>H</em> <em>(supplied</em> <em>on</em> <em>the</em> <em>morning</em> <em>of</em> <em>examination)</em></li>
<li><em>One boiling tube</em></li>
<li><em>One spatula</em></li>
<li><em>Both blue and red litmus papers</em></li>
<li><em>Stop clock/ watch</em></li>
<li><em>Ruler</em></li>
<li><em>10cm<sup>3</sup> measuring cylinder</em></li>
<li><em>Cutting blade / scissors</em></li>
<li><em>6cm<sup>3</sup> length of magnesium ribbon, labelled solid K</em></li>
<li><em>A</em><em>bou</em><em>t</em> <em>50</em><em>c</em><em>m</em><em><sup>3</sup></em> <em>o</em><em>f</em> <em>2</em><em>.</em><em>0</em><em>M</em> <em>h</em><em>y</em><em>d</em><em>r</em><em>o</em><em>c</em><em>h</em><em>l</em><em>o</em><em>r</em><em>i</em><em>c</em> <em>a</em><em>c</em><em>i</em><em>d</em><em>,</em> <em>l</em><em>a</em><em>belle</em><em>d</em> <em>s</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>L</em></li>
<li><em>Means of labeling test-tube holder</em></li>
<li><em>One 100cm<sup>3</sup> beaker</em></li>
<li><em>Test-tube </em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<ul>
<li><em>Distilled</em> <em>water</em></li>
<li><em>Methyl orange indicator</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Bunsen burner</em></li>
<li><em>Concentrated nitric acid supplied with a dropper</em></li>
<li><em>2M hydrochloric acid supplied with a dropper</em></li>
<li><em>1M barium chloride solution supplied with a dropper</em></li>
<li><em>2M</em> <em>sodium</em> <em>hydroxide </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution E is prepared by accurately measuring 10.0cm<sup>3</sup> of concentrated hydrochloric acid (1.18gm/cm<sup>3</sup>) using a burette and adding it to about 500cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution F is prepared by accurately adding 15.3g of solid F in about 800cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution</em> <em>L</em> <em>is</em> <em>prepared</em> <em>by</em> <em>accurately</em> <em>adding</em> <em>172cm<sup>3</sup></em> <em>of</em> <em>concentrated</em> <em>hydrochloric</em> <em>acid (1.18g/cm<sup>3</sup>) to about 500cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
</ol>
<p><strong><em>October / November 2000 Requirements to Candidates</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<ul>
<li><em>About 90cm<sup>3</sup> of solution L</em></li>
<li><em>About 150cm<sup>3</sup> of solution M</em></li>
<li><em>One burette 0 – 50cm<sup>3</sup></em></li>
<li><em>One</em> <em>pipette</em> <em>25cm<sup>3</sup></em></li>
<li><em>One thermometer 0 – 110<sup>0</sup>C</em></li>
<li><em>Two conical flasks</em></li>
<li><em>One filter funnel</em></li>
<li><em>3 filter papers</em></li>
<li><em>10cm<sup>3</sup> of solution P contained in a conical flask</em></li>
<li><em>6 clean dry test-tubes</em></li>
<li><em>50 or 100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>3 g of solid G</em></li>
<li><em>100cm<sup>3</sup> beaker</em></li>
<li><em>Stop clock / watch</em></li>
<li><em>30cm<sup>3</sup> of 2M sodium hydroxide in a beaker</em></li>
<li><em>One 10cm<sup>3</sup> measuring </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Access to</em></strong></p>
<ul>
<li><em>Methyl orange indicator – supplied with dropper</em></li>
<li><em>Phenolphthalein indicator – supplied with dropper</em></li>
<li><em>Distilled</em> <em>water</em></li>
<li><em>2M sodium hydroxide – supplied with dropper</em></li>
<li><em>2M aqueous ammonia – supplied with dropper</em></li>
<li><em>2M</em> <em>nitric</em> <em>acid</em> <em>–</em> <em>supplied</em> <em>with dropper</em></li>
<li><em>2M hydrochloric acid – supplied with dropper</em></li>
<li><em>1 M acidified barium chloride – supplied with </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution L is prepared by dissolving 6g of solid L in 600cm<sup>3</sup> of distilled water and diluting to one</em></li>
</ol>
<p> ;</p>
<p><em>litre of solution.</em></p>
<ol start="2">
<li><em>Solution M is prepared by accurately adding 9cm<sup>3</sup> of concentrated hydrochloric acid (density 18g/cm<sup>3</sup>) to about 500cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></li>
<li><em>Solution P is prepared by mixing 80g of solid Q and 20g of solid R and dissolving the mixture in about 800cm<sup>3</sup> of distilled water then diluting to one litre of </em></li>
</ol>
<p> ;</p>
<p><strong><em>October / November 2001 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<ul>
<li><em>About 20cm<sup>3</sup> of solution </em></li>
<li><em>about 100cm<sup>3</sup> of solution B</em></li>
<li><em>About 60cm<sup>3</sup> of solution C</em></li>
<li><em>About 100cm<sup>3</sup> of solution </em></li>
<li><em>One</em> <em>burette</em></li>
<li><em>One pipette</em></li>
<li><em>Two conical flasks (250cm<sup>3</sup>)</em></li>
<li><em>One filter funnel</em></li>
<li><em>One boiling tube</em></li>
<li><em>One thermometer 0 – 110<sup>0</sup>C</em></li>
<li><em>One 10cm<sup>3</sup> measuring cylinder</em></li>
<li><em>50 or 100cm<sup>3</sup> measuring cylinder</em></li>
<li><em>1g of solid E</em></li>
<li><em>4 clean dry test-tubes</em></li>
<li><em>One test-tube holder</em></li>
<li><em>2</em> <em>blue</em> <em>and</em> <em>2</em> <em>red</em> <em>litmus</em> <em>papers</em></li>
<li><em>0 – 3 g of solid F</em></li>
<li><em>0 – 2g of solid G</em></li>
<li><em>100cm<sup>3</sup> beaker</em></li>
<li><em>One </em></li>
</ul>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>Access to.</em></strong></p>
<ul>
<li><em>Distilled</em> <em>water</em></li>
<li><em>Phenolphthalein indicator</em></li>
<li><em>2M sodium hydroxide – supplied with a dropper</em></li>
<li><em>2M sulphuric acid</em> <em>&#8211; supplied with a dropper</em></li>
<li><em>2M lead (II) nitrate</em> <em>&#8211; supplied with a dropper</em></li>
<li><em>Bromine water &#8211; supplied with a dropper</em></li>
<li><em>Acidified</em> <em>potassium permanganate</em></li>
<li><em>Bunsen </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations.</em></strong></p>
<ol>
<li><em>A is prepared by dissolving 24g of sodium hydroxide pellets in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution</em></li>
<li><em>B is prepared by adding 12cm<sup>3</sup> of hydrochloric acid (specific gravity 18g/cm<sup>3</sup>) (measured</em></li>
</ol>
<p> ;</p>
<p><em>accurately) in about 500cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></p>
<ol start="3">
<li><em>C is made by dissolving 6g of solid C in about 900cm<sup>3</sup> of distilled water and diluting to one litre </em><em>of solution.</em></li>
<li><em>D is prepared by adding 167cm of solution A to 600cm<sup>3</sup> of distilled water and diluting to one litre of solution</em></li>
<li><em>Bromine water is prepared by adding 2ml of liquid bromine to 100cm<sup>3</sup> of distilled water and the mixture stirred well in a fume cupboard</em></li>
<li><em>Acidified potassium permanganate is made by adding 16g of solid potassium permanganate to 400cm<sup>3</sup> of 2M sulphuric acid and diluting to one litre of solution using distilled water.</em></li>
</ol>
<p> ;</p>
<p><strong><em>October / November 2002 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require. </em><strong><em>A</em></strong></p>
<ul>
<li><em>about 120cm<sup>3</sup> of solution A</em></li>
<li><em>about 150cm<sup>3</sup> of solution B</em></li>
<li><em>about 40cm<sup>3</sup> of solution C supplied with a dropper</em></li>
<li><em>about 40cm<sup>3</sup> of solution D supplied with a dropper</em></li>
<li><em>about 150cm<sup>3</sup> of distilled water in a wash bottle</em></li>
<li><em>about</em> <em>2g of solid G</em></li>
<li><em>about 5g of solid H</em></li>
<li><em>10cm of sodium sulphate solution</em></li>
<li><em>about 15cm<sup>3</sup> of solution E supplied with a dropper</em></li>
<li><em>two 200ml or 250ml beaker</em></li>
<li><em>one 10cm<sup>3</sup> measuring cylinder</em></li>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>one 50ml or 100ml measuring cylinder</em></li>
<li><em>15cm<sup>3</sup> of solution F</em></li>
<li><em>one boiling tube</em></li>
<li><em>one filter funnel</em></li>
<li><em>two pieces of filter paper (whatman 1 size 11.0cm)</em></li>
<li><em>6 clean dry test-tubes</em></li>
<li><em>one test-tube holder</em></li>
<li><em>one clean metallic spatula</em></li>
<li><em>two labels</em></li>
<li><em>one stopwatch / clock</em></li>
<li><em>Atleast 6cm length of universal indicator paper (full range) pH 1 – </em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Access to</em></strong>
<ul>
<li><em>Bunsen burner (in good working condition).</em></li>
<li><em>Barium nitrate solution supplied with a dropper</em></li>
<li><em>2M sodium hydroxide – supplied with a dropper</em></li>
<li><em>2M hydrochloric acid</em> <em>&#8211; supplied with a dropper</em></li>
<li><em>2M aqueous ammonia &#8211; supplied with a dropper</em></li>
<li><em>pH chart pH 1 &#8211; 14</em></li>
<li><em>bromine water &#8211; supplied with a dropper</em></li>
<li><em>acidified potassium permanganate supplied with a dropper</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution A is prepared by adding 200cm<sup>3</sup> of fresh 20 volume hydrogen peroxide to about 600cm<sup>3</sup></em></li>
</ol>
<p> ;</p>
<p><em>of distilled water and diluting to one litre of solution. (This solution should be prepared one day before the day of examination, stored in Stoppard container and supplied on the morning of the </em><em>examination).</em></p>
<ol start="2">
<li><em>Solution B is 2M sulphuric acid</em></li>
<li><em>Solution</em> <em>C</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>12g</em> <em>of</em> <em>solid</em> <em>C</em> <em>in</em> <em>about</em> <em>800cm<sup>3</sup></em> <em>of</em> <em>distilled</em> <em>water</em> <em>and</em> <em>diluting</em> <em>to one litre of </em></li>
<li><em>Solution D is prepared by adding 10g of solid D in about 700cm<sup>3</sup> of distilled water and diluting to </em><em>one litre of </em></li>
<li><em>Solution</em> <em>E</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>10g</em> <em>of</em> <em>solid</em> <em>E in about 600cm<sup>3</sup> of warm distilled water and diluting with warm water to one litre of </em></li>
<li><em>Solution F is prepared by dissolving 30g of solid F in about 900cm<sup>3</sup> of distilled water and diluting </em><em>to one litre of </em></li>
</ol>
<p><strong><em>October / November 2003 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<p><strong><em>A.</em></strong></p>
<ul>
<li><em>about 80cm<sup>3</sup> of solution P</em></li>
<li><em>about 120cm<sup>3</sup> of solution Q</em></li>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>one pipette 25ml</em></li>
<li><em>two conical flasks 250ml</em></li>
<li><em>9g of solid S weighed accurately</em></li>
<li><em>35cm<sup>3</sup> of solution T</em></li>
<li><em>one thermometer 0 – 110<sup>o</sup>C</em></li>
<li><em>one 100ml beaker</em></li>
<li><em>one 50ml or 100ml measuring cylinder</em></li>
<li><em>about 200ml of distilled water in a wash bottle</em></li>
<li><em>3g of solid V</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>one boiling tube</em></li>
<li><em>one spatula</em></li>
<li><em>6 clean dry test-tubes</em></li>
<li><em>1ml of 5M barium chloride supplied in a test-tube and labelled 0.5MBaCl</em><em>2</em></li>
<li><em>2cm<sup>3</sup></em> <em>of</em> <em>2M</em> <em>hydrochloric</em> <em>acid</em> <em>supplied</em> <em>in</em> <em>a</em> <em>test-tube</em> <em>and</em> <em>labelled 2MHCl</em></li>
<li><em>About 35cm<sup>3</sup> of solution </em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Access to</em></strong>
<ul>
<li><em>2M sodium hydroxide</em></li>
<li><em>1M lead (II) nitrate solution</em></li>
<li><em>Solution W</em></li>
</ul>
</li>
</ol>
<p><em>These</em> <em>solutions</em> <em>should</em> <em>be</em> <em>supplied</em> <em>with droppers.</em></p>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution P is prepared by dissolving 2g of solid P in 400cm<sup>3</sup> of 1M sulphuric acid and diluting to one litre of solution using distilled water.</em></li>
<li><em>Solution Q is prepared by dissolving 7g of solid Q in 400cm<sup>3</sup> of 1M sulphuric acid and diluting to one litre of solution using distilled water. This solution is to be prepared in the morning of the examination and supplied to candidates in containers sealed with aluminum foil. (The solid should be dissolved in the sulphuric acid immediately after weighing).</em></li>
<li><em>Solution W is prepared by dissolving 5g of solid W in 500cm<sup>3</sup> of 1M sulphuric acid and diluting to one litre of solution using distilled </em></li>
</ol>
<p> ;</p>
<ol start="4">
<li><em>Solution R is prepared by dissolving exactly 0g of sodium hydroxide pellets in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution and allowed to cool to room temperature.</em></li>
<li><em>Solution T is prepared by dissolving 63g of solid T in about 900cm<sup>3</sup> of distilled water and diluting to one litre of solution and allowed to attain room </em></li>
</ol>
<p> ;</p>
<p><em>NB/ The quantities in the above preparations will depend on the number of candidates in a centre.</em></p>
<p> ;</p>
<p><strong><em>October / November 2004 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<p><em>A.</em></p>
<ul>
<li><em>Exactly</em> <em>3cm<sup>3</sup></em> <em>length</em> <em>of</em> <em>solid</em></li>
<li><em>About 80cm<sup>3</sup> of solution B</em></li>
<li><em>About 120cm<sup>3</sup> of solution C</em></li>
<li><em>one</em> <em>burette</em> <em>(0</em> <em>–</em> <em>50ml)</em></li>
<li><em>one pipette 25ml</em></li>
<li><em>one thermometer (0 – 110<sup>0</sup>) C</em></li>
<li><em>one 100ml beaker</em></li>
<li><em>two 250ml conical flasks</em></li>
<li><em>one stopwatch / clock</em></li>
<li><em>6 clean dry test-tubes</em></li>
<li><em>one boiling tube</em></li>
<li><em>about 200cm<sup>3</sup> of distilled water in a wash </em></li>
<li><em>one label</em></li>
<li><em>about 5cm<sup>3</sup></em> <em>of solution E in a test-tube</em></li>
<li><em>about</em> <em>5cm<sup>3</sup></em> <em>of</em> <em>solution</em> <em>F</em> <em>in</em> <em>a test tube</em></li>
<li><em>about</em> <em>5cm<sup>3</sup></em> <em>of</em> <em>solution</em> <em>G</em> <em>in</em> <em>a</em> <em>test</em> <em>tube</em></li>
<li><em>about</em> <em>6cm<sup>3</sup></em> <em>of</em> <em>solution</em> <em>H in a test tube</em></li>
<li><em>one clean glass rod</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>1 ml of chlorine water supplied in a -tube and sealed with aluminium foil</em></li>
<li><em>2 ml of 1% bromine water supplied in a test-tube and sealed with aluminum </em></li>
</ul>
<p> ;</p>
<ol>
<li><strong><em>Access to</em></strong>
<ul>
<li><em>2M</em> <em>sodium</em> <em>hydroxide</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>phenolphthalein indicator</em></li>
<li><em>5M barium chloride supplied with a dropper</em></li>
<li><em>05M lead (II) nitrate solution supplied with a dropper</em></li>
<li><em>Bunsen</em> <em>burner</em> <em>in</em> <em>good</em> <em>working</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution B is prepared by dissolving 2 cm<sup>3</sup> of concentrated hydrochloric acid density 1.18g/cm<sup>3</sup> in about 600cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></li>
<li><em>Solution C is prepared by dissolving 12g of solid sodium hydroxide pellets in about 800cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution E is prepared by dissolving 60g of solid E in about 900cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution F is prepared by dissolving 30g of solid F in about 500cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution G is prepared by dissolving 30g of solid G in about 700cm<sup>3</sup> of distilled water and diluting</em></li>
</ol>
<p> ;</p>
<p><em>to one litre of solution.</em></p>
<ol start="6">
<li><em>Solution H is prepared by dissolving 60g of solid H in about 600cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Chlorine H</em><em>2</em><em>O is prepared by dissolving 250cm<sup>3</sup> of 5% chlorine H</em><em>2</em><em>) (5% sodium hypochloric) to 750cm<sup>3</sup> of distilled H</em><em>2</em></li>
<li><em>1% bromine H</em><em>2</em><em>O is prepared by adding 1cm<sup>3</sup> of liquid bromine to 100 of distilled H</em><em>2</em><em>O and shaking </em><em>one mixture well to dissolve (This mixture will dissolve ( this should be done in the same chamber)</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 2005 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<p><em>A.</em></p>
<ul>
<li><em>About 100cm<sup>3</sup> of solution K</em></li>
<li><em>About 75cm<sup>3</sup> of solution L</em></li>
<li><em>One</em> <em>burette</em> <em>0 – 50 </em></li>
<li><em>one pipette 25ml</em></li>
<li><em>5g of solid M accurately weighed and supplied in a clean dry test-tube.</em></li>
<li><em>one tripod stand with a wire gauze</em></li>
<li><em>one 200ml or 250ml beaker</em></li>
<li><em>one Bunsen burner</em></li>
<li><em>one thermometer 0 – 110<sup>0</sup>C</em></li>
<li><em>one stopwatch / clock</em></li>
<li><em>one test-tube holder</em></li>
<li><em>about 5g of solid N</em></li>
<li><em>5 clean and dry test-tubes</em></li>
<li><em>one boiling tube</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>about 10cm<sup>3</sup> of solution P</em></li>
<li><em>about 5g of solid Q</em></li>
<li><em>about 1g of solid sodium hydrogen </em></li>
<li><em>one blue and one red litmus paper</em></li>
<li><em>5 pieces of filter paper</em></li>
<li><em>one spatula</em></li>
<li><em>about 150cm<sup>3</sup></em> <em>of distilled water supplied in a wash bottle</em></li>
<li><em>two 100ml beakers</em></li>
<li><em>one filter funnel</em></li>
<li><em>one 100ml measuring cylinder</em></li>
<li><em>a</em> <em>small</em> <em>roll</em> <em>of</em> <em>tissue</em> <em>paper</em> <em>(approximately</em> <em>25cm<sup>3</sup></em> <em>long)</em></li>
</ul>
<p> ;</p>
<ol>
<li><em>Access to</em>
<ul>
<li><em>2M</em> <em>aqueous</em> <em>ammonia</em></li>
<li><em>5M barium nitrate solution</em></li>
<li><em>2M</em> <em>hydrochloric</em></li>
</ul>
</li>
</ol>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<p><em>1 Solution K is prepared by dissolving 37.32g of sodium hydroxide pellets in about 600cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></p>
<ol start="2">
<li><em>Solution</em> <em>L</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>0g</em> <em>of</em> <em>solid</em> <em>L</em> <em>in</em> <em>about</em> <em>600cm<sup>3</sup> of distilled water and</em></li>
</ol>
<p> ;</p>
<p><em>diluting</em> <em>to</em> <em>one</em> <em>litre</em> <em>of solution.</em></p>
<ol start="3">
<li><em>Solution</em> <em>P</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>50g</em> <em>of</em> <em>solid</em> <em>P</em> <em>in</em> <em>about</em> <em>700cm<sup>3</sup></em> <em>of</em> <em>distilled</em> <em>water and diluting to one litre of </em></li>
</ol>
<p> ;</p>
<p><strong><em>October / November 2006 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require</em></p>
<ul>
<li><em>5g of solid A supplied in a boiling tube</em></li>
<li><em>110cm of solution B</em></li>
<li><em>about 450cm<sup>3</sup> of distilled water supplied in a wash bottle</em></li>
<li><em>about 5g of solid E supplied in a dry stoppered container</em></li>
<li><em>about 5g of solid F supplied in a dry stoppered container</em></li>
<li><em>about 10cm<sup>3</sup> of aqueous sodium sulphate supplied in</em></li>
<li><em>one burette 0 – 50mls</em></li>
<li><em>one pipette 25ml</em></li>
<li><em>one pipette filler</em></li>
<li><em>one thermometer -10 <sup>o</sup>C – 110 o C</em></li>
<li><em>one</em> <em>250ml</em> <em>volumetric</em> <em>flask</em></li>
<li><em>two 250mls conical flask</em></li>
<li><em>one Bunsen burner</em></li>
<li><em>one tripped sled and wire gauge</em></li>
<li><em>5 dry test tubes</em></li>
<li><em>one boiling tube</em></li>
<li><em>2</em> <em>filter</em> <em>papers</em> <em>(whatman</em> <em>1</em> <em>125mm)</em></li>
<li><em>one filter funnel</em></li>
<li><em>one filter holder</em></li>
<li><em>one metallic spatula</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>means of labeling</em></li>
<li><em>one clean </em><strong><em>Access to:</em></strong></li>
<li><em>2M NaOH supplied with a dropper</em></li>
<li><em>2M HCl</em></li>
<li><em>Bromine H</em><em>2</em><em>O supplied with a dropper</em></li>
<li><em>Phenolphthalein indictor supplied with a dropper</em></li>
<li><em>Wall </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution B is prepared by dissolving 48g of solution B in about 400cm of 2M sulphuric acid and diluting to one litre of solution with distilled water.</em></li>
<li><em>Aqueous sodium sulphate is prepared by dissolving 10g of solid Na SO</em><em>4 </em><em>Diluting with distilled </em><em>water to one litre of solution</em></li>
<li><em>Bromine water is prepared by diluting 1ml of liquid bromine with 100cm<sup>3</sup> of distilled water in a </em><em>fume cupboard</em></li>
<li><em>Solid A should be weight accurately in a fume clipboard or a well ventilated room.</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October / November 2007 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p> ;</p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<p> ;</p>
<ul>
<li><em>About 120cm<sup>3</sup> of solution </em></li>
<li><em>about 120cm<sup>3</sup> of solution B</em></li>
<li><em>About 100cm<sup>3</sup> of solution </em></li>
<li><em>one pipette 0ml</em></li>
<li><em>one pipette filler</em></li>
<li><em>one</em> <em>volumetric</em> <em>flask</em> <em>250ml</em></li>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>two conical flasks</em></li>
<li><em>8 clean dry test-tubes</em></li>
<li><em>test-tube rack</em></li>
<li><em>one</em> <em>thermometer</em> <em>–</em> <em>10<sup>0</sup>C</em> <em>– </em><em>110<sup>0</sup>C</em></li>
<li><em>two boiling tubes</em></li>
<li><em>about 5g of solid E in a stoppered container</em></li>
<li><em>one blue and one red litmus paper</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>about 500ml of distilled water in a wash bottle</em></li>
<li><em>one test-tube holder</em></li>
<li><em>one PH chart paper range 1 to 14</em></li>
<li><em>about 2cm<sup>3</sup> of solution G</em></li>
<li><em>1g of sodium carbonate (solid)</em></li>
<li><em>one watch glass</em></li>
<li><em>about 5cm<sup>3</sup> of solution H</em></li>
<li><em>about 10cm<sup>3</sup> of ethanol (absolute) in a Stoppard container labelled liquid F</em></li>
<li><em>spatula</em></li>
<li><em>two clean dropper</em></li>
<li><em>Means</em> <em>of</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<ul>
<li><em>Methyl orange indicator supplied with a dropper</em></li>
<li><em>Bunsen burner</em></li>
<li><em>universal indicator supplied with a dropper</em></li>
<li><em>2M aqueous ammonia supplied with a dropper</em></li>
<li><em>5M barium nitrate solution</em></li>
<li><em>2M</em> <em>nitric</em> <em>acid</em></li>
<li><em>Wall </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution A is prepared by dissolving 0cm<sup>3</sup> of 1.84g/cm (98%) concentrated sulphuric acid in about 600cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></li>
<li><em>Solution</em> <em>B</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>0g</em> <em>solid</em> <em>B</em> <em>in</em> <em>about</em> <em>500cm<sup>3</sup></em> <em>of distilled water and diluting to one litre of solution.</em></li>
<li><em>Solution</em> <em>C</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>0g</em> <em>of</em> <em>sodium</em> <em>hydroxide</em> <em>pellets in about 700cm of distilled water and diluting to one litre of solution.</em></li>
<li><em>Solution G is prepared by dissolving 100g of solid G in about 400cm<sup>3</sup> of distilled water and diluting to one litre of </em></li>
<li><em>Solution H is prepared by dissolving 25g solid H in about 600cm<sup>3</sup> of 2M sulphuric acid and diluting to one litre of </em></li>
</ol>
<p> ;</p>
<p><em>NB/</em> <em>The</em> <em>test-tubes</em> <em>provided</em> <em>should</em> <em>have</em> <em>a</em> <em>capacity</em> <em>of</em> <em>at</em> <em>least</em> <em>15cm<sup>3</sup>.</em></p>
<p> ;</p>
<p><strong><em>October / November 2008</em></strong></p>
<p><strong> </strong></p>
<p><strong><em>Requirements to candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<ul>
<li><em>1g of solid A weighed accurately and supplied in a dry stoppered container</em></li>
<li><em>about 60cm<sup>3</sup> of solution B</em></li>
<li><em>about 130cm of sodium hydroxide solution</em></li>
<li><em>one</em> <em>thermometer</em> <em>– </em><em>10 <sup>o</sup>C </em><em>– </em><em>110 <sup>o</sup>C</em></li>
<li><em>one stop watch/clock</em></li>
<li><em>one 100ml beaker</em></li>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>one pipette 25ml</em></li>
<li><em>one bolometric flask 250ml</em></li>
<li><em>about 500cm<sup>3</sup> of distilled water supplied in a wash bottle</em></li>
<li><em>one</em> <em>label</em> <em>or</em> <em>means</em> <em>of</em> <em>labeling</em></li>
<li><em>one pipette filler</em></li>
<li><em>two conical flasks</em></li>
<li><em>about</em> <em>5g</em> <em>of</em> <em>solid</em> <em>D</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>2g of solid E supplied in a stoppered container.</em></li>
<li><em>about 5g of solid F supplied in a stoppered container</em></li>
<li><em>six clean dry test-tubes</em></li>
<li><em>one blue and one red litmus paper</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>one metallic spatula</em></li>
<li><em>about 3g of sodium hydrogen carbonate (solid)</em></li>
<li><em>one test-tube holder</em></li>
<li><em>15cm<sup>3</sup> of 2M hydrochloric </em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to.</em></strong></p>
<ul>
<li><em>Bunsen burner</em></li>
<li><em>2M aqueous ammonia supplied with a dropper</em></li>
<li><em>acidified potassium dichromate (IV) supplied with a dropper</em></li>
<li><em>acidified potassium manganate (VII) supplied with a dropper</em></li>
<li><em>Phenolphthalein indicator supplied with a </em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution</em> <em>B</em> <em>is</em> <em>prepared</em> <em>by</em> <em>adding</em> <em>0cm<sup>3</sup></em> <em>(1.18g/cm)</em> <em>of</em> <em>concentrated</em> <em>hydrochloric acid to about 500cm<sup>3</sup> of distilled water and diluting to one litre of solution.</em></li>
<li><em>Acidified potassium dichromate (VI) is prepared by dissolving 25g of solid potassium dichromate</em></li>
</ol>
<p><em>(VI) in about 600cm<sup>3</sup> of 2M sulphuric acid and diluting to one litre of solution.</em></p>
<ol start="3">
<li><em>Acid KMnO</em><em>4 </em><em>16 g in 500cm<sup>3</sup> of 2M H</em><em>2</em><em>SO</em><em>4 </em><em>dilute to 1l.</em></li>
<li><em>NaOH</em><u> </u><em>0g</em><em><u> </u></em><em>700cm<sup>3</sup> H</em><em>2</em><em>O</em><em><u> </u></em><em>diluting to 1 litre</em></li>
</ol>
<p> ;</p>
<p><strong><em>October / November 2009 </em></strong><strong><em>Requirements to Candidates.</em></strong></p>
<p><em>In addition to the fittings and apparatus found in a chemistry laboratory, each candidate will require.</em></p>
<ul>
<li><em>8g of solid a weighed accurately and supplied in a stopperd container.</em></li>
<li><em>about 60cm<sup>3</sup> of solution G</em></li>
<li><em>one</em> <em>250ml</em> <em>volumetric</em> <em>flask</em></li>
<li><em>one</em> <em>pipette,</em> <em>250ml</em> <em>and a pipette filler</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>2 labels</em></li>
<li><em>about 120cm<sup>3</sup> of solution C</em></li>
<li><em>three</em> <em>dry</em> <em>conical</em> <em>flasks</em> <em>(250ml)</em></li>
<li><em>one dry filter funnel</em></li>
<li><em>one</em> <em>250ml</em> <em>dry beaker</em></li>
<li><em>one filter paper whatman 125mm 1</em></li>
<li><em>5g</em> <em>of</em> <em>solid</em> <em>E</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>six dry test tubes</em></li>
<li><em>one 100ml measuring cylinder</em></li>
<li><em>one 10ml measuring cylinder</em></li>
<li><em>about 500cm<sup>3</sup> of distilled water supplied in a wash bottle</em></li>
<li><em>one oiling tube</em></li>
<li><em>one glass rod</em></li>
<li><em>5g solid F supplied in a stoppered container.</em></li>
<li><em>5cm<sup>3</sup> of absolute ethanol supplied in a stoppered container on the day of </em></li>
<li><em>2g of solid sodium hydrogen carbonate</em></li>
<li><em>spatula</em></li>
<li><em>one test-tube holder</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to:</em></strong></p>
<ul>
<li><em>Bromine water supplied with a dropper</em></li>
<li><em>acidified potassium dichromate (VI) supplied with a dropper</em></li>
<li><em>2M aqueous ammonia supplied with a dropper</em></li>
<li><em>Bunsen burner</em></li>
<li><em>tissue paper</em></li>
<li><em>aqueous lead (II) nitrate supplied with a dropper</em></li>
<li><em>universal</em> <em>indicator</em> <em>solution</em> <em>pH 1 – 14 supplied with a dropper</em></li>
<li><em>pH</em> <em>chart</em> <em>range</em> <em>1 – 14</em></li>
<li><em>freshly prepared methyl orange indicator supplied with a dropper</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution B is prepared by dissolving 215cm<sup>3</sup> of HCl of density 1.18g/cm<sup>3</sup> in abut 500cm<sup>3</sup> of distilled water and making to one litre of solution using distilled water and labelled solution B.</em></li>
<li><em>Solution C is prepared by dissolving 0g of NaOH pellets in about 800cm<sup>3</sup> of distilled water and making to one litre of solution using distilled water and labelled solution C.</em></li>
<li><em>Acidified potassium dichromate (VI) is prepared by dissolving 25g of solid potassium dichromate</em></li>
</ol>
<p><em>(VI) in about 400cm<sup>3</sup> of 2M H</em><em>2</em><em>SO</em><em>4 </em><em>acid and making to one litre of solution using distilled water </em><em>and labelled acidified potassium dichromate (VI) solution.</em></p>
<ol start="4">
<li><em>Bromine water is prepared by adding 1cm of liquid bromine to 100cm<sup>3</sup> of distilled water and stirring well in a well in an efficient fume </em></li>
<li><em>Lead (II) nitrate is prepared by adding 30g of solid lead (II) nitrate in about 700cm<sup>3</sup> of distilled water and making up to one litre of solution using distilled water and labelled lead (II) nitrate </em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 2010 Candidates Requirements</em></strong></p>
<p><em>In addition to the apparatus and fittings found in a chemistry laboratory, each candidate will require the </em><em>following;</em></p>
<p> ;</p>
<ul>
<li><em>About 150cm<sup>3</sup> of solution A labeled solution A</em></li>
<li><em>About 150cm<sup>3</sup> of solution B labeled solution B</em></li>
<li><em>About 80cm<sup>3</sup> of solution C labeled solution C</em></li>
<li><em>One pipette 0ml</em></li>
<li><em>One pipette filler</em></li>
<li><em>One volumetric flask (250.0ml)</em></li>
<li><em>Four labels</em></li>
<li><em>About 500cm<sup>3</sup> of distilled water</em></li>
<li><em>One burette 0ml</em></li>
<li><em>Three conical flasks</em></li>
<li><em>One</em> <em>10ml</em> <em>measuring cylinder</em></li>
<li><em>One 100ml measuring cylinder</em></li>
<li><em>Two</em> <em>boiling</em> <em>tubes</em></li>
<li><em>One</em> <em>thermometer</em> <em>-10<sup>0</sup> C to 110<sup>0</sup>C</em></li>
<li><em>About</em> <em>5</em> <em>g</em> <em>of</em> <em>solid</em> <em>E</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stopper</em> <em>container</em></li>
<li><em>Six clean dry test-tubes</em></li>
<li><em>About 1g of solid F supplied in a stopper container</em></li>
<li><em>About 5g of solid G supplied in a stopper container</em></li>
<li><em>pH chart</em> <em>1-14; and universal indicator solution supplied with a dropper</em></li>
<li><em>One 100ml beaker</em></li>
<li><em>One metallic spatula</em></li>
<li><em>One clean dropper</em></li>
</ul>
<p> ;</p>
<p><strong><em>Access to</em></strong></p>
<ul>
<li><em>Phenolphthalein indicator supplied with</em> <em>a dropper</em></li>
<li><em>2</em> <em>M</em> <em>sulphuric</em> <em>(VI)</em> <em>acid</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>2</em> <em>M</em> <em>sodium</em> <em>hydroxide</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>5M</em> <em>potassium</em> <em>iodide</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>Bromine water supplied with a dropper</em></li>
<li><em>Acidified potassium manganate (VII) supplied with a dropper</em></li>
</ul>
<p> ;</p>
<ul>
<li><em>Bunsen burner</em></li>
</ul>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution A is prepared by taking 190.0cm<sup>3</sup> of concentrated hydrochloric acid (Specific gravity 1.18) adding it to 600cm<sup>3</sup> of distilled water in a 1 litre volumetric flask and diluting it to the mark. Label </em><em>this solution as solution </em></li>
</ol>
<p> ;</p>
<ol start="2">
<li><em>Solution</em> <em>B</em> <em>is</em> <em>prepared</em> <em>by</em> <em>dissolving</em> <em>0g</em> <em>of</em> <em>sodium</em> <em>hydroxide pellets in 800cm of distilled water and diluting it to the mark. Label it as solution B.</em></li>
</ol>
<p> ;</p>
<ol start="3">
<li><em>Solution C is prepared by dissolving 25g of solid C in 600cm<sup>3</sup> of distilled water and diluting it to the Label this as solution C</em></li>
</ol>
<p> ;</p>
<ol start="4">
<li><em>Bromine water is prepared by taking 1cm<sup>3</sup> of liquid bromine and dissolving it in 100cm<sup>3</sup> of distilled water in a fume This must be fleshly prepared and supplied in a dropper battle</em></li>
</ol>
<p> ;</p>
<ol start="5">
<li><em>Acidified potassium manganate (VII) is prepared by dissolving 16g of solid potassium manganate (VII) in about 600cm<sup>3</sup> of 2M Sulphuric (VI) acid and adding distilled water to make 1 litre.</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 2011</em></strong></p>
<p><strong> </strong></p>
<p><em>In addition to the apparatus and fittings found in a chemistry laboratory, each candidate will require the </em><em>following;</em></p>
<p> ;</p>
<p><strong><em>A.</em></strong></p>
<p><strong> </strong></p>
<ol>
<li><em>60g of solid A</em> <em>weighed accurately and supplied in a stoppered container.</em></li>
<li><em>About 80cm<sup>3</sup> of solution </em></li>
<li><em>about 200cm<sup>3</sup> of solution C</em></li>
<li><em>One</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>One pipette 0ml</em></li>
<li><em>One pipette filler</em></li>
<li><em>One</em> <em>250ml</em> <em>volumetric</em> <em>flask</em></li>
<li><em>Three 250ml conical flasks</em></li>
<li><em>4 labels</em></li>
<li><em>About</em> <em>5g</em> <em>of</em> <em>solid</em> <em>D</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>one spatula</em></li>
<li><em>Six clean dry test – tubes</em></li>
<li><em>One boiling tube</em></li>
<li><em>one</em> <em>red</em> <em>and</em> <em>one</em> <em>blue</em> <em>litmus</em> <em>papers</em></li>
<li><em>4cm<sup>3</sup> of solution E</em> <em>in a test tube and labeled solution </em></li>
<li><em>about</em> <em>500cm<sup>3</sup> of</em> <em>distilled water in a wash bottle</em></li>
<li><em>about 10cm<sup>3</sup> of liquid F supplied in a stoppered test tube and labeled liquid </em><strong><em>(Liquid </em></strong><em>F is absolute ethanol)</em></li>
<li><em>One clean and dry watch glass</em></li>
<li><em>2gm of solid sodium hydrogen carbonate</em></li>
<li><em>one test – tube holder</em></li>
<li><em>one stop watch</em></li>
<li><em>One 10ml measuring cylinder</em></li>
</ol>
<p> ;</p>
<ol>
<li><strong><em>ACCESS TO:</em></strong></li>
</ol>
<p> ;</p>
<ol>
<li><em>Bunsen burner</em></li>
<li><em>Phenolphthalein indicator supplied with a dropper</em></li>
<li><em>2M sodium hydroxide supplied with a </em></li>
<li><em>20V hydrogen peroxide supplied with a dropper </em><strong><em>October /November 2012</em></strong></li>
</ol>
<p><em>In addition to the apparatus and reagents found in a chemistry laboratory, each candidate will require the </em><em>following:</em></p>
<p> ;</p>
<ol>
<li><em>about 150cm<sup>3</sup> of solution A</em></li>
<li><em>about 100cm<sup>3</sup> of solution B</em></li>
<li><em>about 45cm<sup>3</sup> of solution C</em></li>
<li><em>about 50cm<sup>3</sup> aqueous potassium iodide</em></li>
<li><em>about 60cm<sup>3</sup> of solution D</em></li>
<li><em>about 50cm<sup>3</sup> of 2M sulphuric (vi) acid</em></li>
<li><em>one pipette 0ml</em></li>
<li><em>One pipette filler</em></li>
<li><em>One</em> <em>burette</em> <em>0</em> <em>–</em> <em>50ml</em></li>
<li><em>two 250ml conical flasks</em></li>
<li><em>One</em> <em>10ml</em> <em>measuring cylinder</em></li>
<li><em>Six dry test tubes</em></li>
<li><em>One stop watch or clock</em></li>
<li><em>Test – tube rack</em></li>
<li><em>about</em> <em>5g</em> <em>of</em> <em>solid</em> <em>E</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>two boiling tubes</em></li>
<li><em>one</em> <em>red</em> <em>and</em> <em>one</em> <em>blue</em> <em>litmus</em> <em>papers</em></li>
<li><em>test – tube holder</em></li>
<li><em>3</em> <em>x1</em> <em>cm</em> <em>piece</em> <em>of</em> <em>aluminium</em> <em>foil</em></li>
<li><em>about</em> <em>5 of solid F in a stoppered container</em></li>
<li><em>about 2g of solid sodium hydrogen carbonate</em></li>
<li><em>about 20cm<sup>3</sup> of 2M hydrochloric acid</em></li>
<li><em>three 5cm whatman No. 1 filter papers</em></li>
<li><em>one filter funnel</em></li>
<li><em>one metallic spatula</em></li>
<li><em>about 500cm<sup>3</sup> of distilled water</em></li>
<li><em>one 100ml beaker</em></li>
<li><em>8 small labels</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><em>Access to:</em></p>
<p> ;</p>
<ol>
<li><em>aqueous</em> <em>sodium</em> <em>sulphate</em> <em>supplied with a dropper</em></li>
<li><em>aqueous</em> <em>sodium</em> <em>chloride</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>aqueous barium nitrate supplied with</em> <em>a dropper</em></li>
<li><em>aqueous lead (II) nitrate supplied with a dropper</em></li>
<li><em>2M</em> <em>sodium</em> <em>hydroxide</em> <em>supplied</em> <em>with</em> <em>a</em> <em>dropper</em></li>
<li><em>Bunsen burner</em></li>
<li><em>Bromine water supplied with a dropper</em></li>
</ol>
<p> ;</p>
<p><em>N</em><em>B</em><em>:</em><em> Solids A, C, D, E and F will be supplied by the Kenya National Examination Council</em></p>
<p> ;</p>
<ol>
<li><em>Solution <strong>A is </strong>prepared by dissolving 20g of solid A in about 600cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this solution as solution A.</em></li>
<li><em>Solution <strong>B </strong>is prepared by dissolving 40g of solid sodium thiosulphate (Na</em><em>2</em><em>S</em><em>2</em><em>O</em><em>3. </em><em>5H</em><em>2</em><em>O) in about </em><em>800cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this as solution B.</em></li>
<li><em>Solution <strong>C </strong>is prepared by dissolving 40g of solid <strong>C </strong>in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this as solution <strong>C.</strong></em></li>
<li><em>Potassium iodide is prepared by dissolving 5gm of solid potassium iodide in about 800cm<sup>3</sup> of distilled water and diluting to ne litre of Label this as potassium iodide.</em></li>
<li><em>Solution <strong>D </strong>is prepared by placing 10g of solid <strong>D </strong>in 1000cm<sup>3</sup> of distilled Heating the mixture to boiling and allowing it to cool to room temperature. Label this as solution <strong>D</strong></em></li>
<li><em>Sodium sulphate solution is made by dissolving 14.2g of solid sodium sulphate in about 800cm<sup>3</sup> of distilled water and diluting to one litre of Label this as aqueous sodium sulphate.</em></li>
<li><em>Sodium chloride solution is made by dissolving 85g of solid sodium chloride in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this as aqueous sodium chloride.</em></li>
<li><em>Barium nitrate solution is prepared by dissolving 0gm of solid barium nitrate in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this as aqueous barium nitrate.</em></li>
<li><em>Lead (II) nitrate is prepared by dissolving 0gm of solid lead (II) nitrate in about 800cm<sup>3</sup> of distilled water and diluting to one litre of solution. Label this as aqueous lead (II) nitrate.</em></li>
<li><em>Bromine water is prepared by adding 1cm<sup>3</sup> of liquid bromine in 100cm<sup>3</sup> of distilled water and shaking well in a fume Label this as bromine water.</em></li>
</ol>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p><strong><em>October /November 2013</em></strong></p>
<p><strong> </strong></p>
<p><em>In addition to the apparatus and reagents found in a chemistry laboratory, each candidate will require the </em><em>following:</em></p>
<p> ;</p>
<ol>
<li><em>about 80cm<sup>3</sup> of solution A</em></li>
<li><em>60g</em> <em>of</em> <em>solid</em> <em>B</em> <em>weighed</em> <em>accurately</em> <em>and</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>about 100cm<sup>3</sup> of solution C</em></li>
<li><em>one</em> <em>burette</em> <em>0</em> <em>–</em> <em>0</em> <em>ml;</em></li>
<li><em>one 100ml beaker</em></li>
<li><em>one thermometer &#8211; 10<sup>0</sup> – 110<sup>0</sup>C</em></li>
<li><em>One stop watch/ clock;</em></li>
<li><em>one</em> <em>250ml</em> <em>volumetric</em> <em>flask</em></li>
<li><em>One 10ml measuring cylinder</em></li>
<li><em>about 70cm<sup>3</sup> of 2M sulphuric acid (VI) acid</em></li>
<li><em>about 500cm<sup>3</sup> of distilled water supplied in a wash bottle</em></li>
</ol>
<p> ;</p>
<ol start="12">
<li><em>two labels</em></li>
<li><em>one 0ml pipette</em></li>
<li><em>one pipette filler</em></li>
<li><em>t</em><em>w</em><em>o</em><em> 250ml conical flasks;</em></li>
<li><em>0g</em> <em>of</em> <em>solid</em> <em>E</em> <em>supplied</em> <em>in</em> <em>a</em> <em>stoppered</em> <em>container</em></li>
<li><em>two boiling tubes</em></li>
<li><em>3 filter papers ( whatman no 1 125mm)</em></li>
<li><em>One filler funnel</em></li>
<li><em>six dry test tubes</em></li>
<li><em>One burning splint</em></li>
<li><em>5g of solid G supplied in a stoppered container</em></li>
<li><em>One metallic spatula</em></li>
<li><em>2g of solid sodium hydrogen carbonate supplied in a stoppered</em></li>
<li><em>Fresh universal indicator</em></li>
<li><em>pH chart range 1- 14</em></li>
<li><em>One test tube holder </em><strong><em>Access to:</em></strong></li>
<li><em>Bunsen burner</em></li>
<li><em>2M hydrochloric acid</em></li>
<li><em>2M aqueous ammonia supplied with a dropper</em></li>
<li><em>5 barium nitrate supplied with a dropper</em></li>
</ol>
<p> ;</p>
<p><strong><em>Preparations</em></strong></p>
<ol>
<li><em>Solution A is prepared by dissolving 125.2g of hydrated copper (II) sulphate is about 800cm<sup>3</sup> of distilled water and diluting tone litre of solution and labeled solution </em></li>
<li><em>S</em><em>o</em><em>l</em><em>u</em><em>t</em><em>i</em><em>o</em><em>n</em> <em>C</em> <em>i</em><em>s</em> <em>p</em><em>r</em><em>e</em><em>pa</em><em>r</em><em>e</em><em>d</em> <em>b</em><em>y</em> <em>placin</em><em>g</em> <em>3</em><em>.</em><em>2</em><em>g</em> <em>o</em><em>f</em> <em>s</em><em>o</em><em>l</em><em>i</em><em>d</em> <em>C</em> <em>i</em><em>n</em> <em>o</em><em>n</em><em>e</em> <em>l</em><em>i</em><em>t</em><em>r</em><em>e</em> <em>v</em><em>o</em><em>l</em><em>u</em><em>m</em><em>e</em><em>t</em><em>r</em><em>i</em><em>c</em> <em>f</em><em>l</em><em>a</em><em>s</em><em>k, adding 100cm<sup>3</sup> of 2M sulphuric (VI) acid followed by 700cm<sup>3</sup> of distilled water shaking to dissolve then diluting to the Label this as solution C.</em></li>
<li><em>Solid E is prepared by weighing 0.5 of solid E</em><em>1 </em><em>and 0.5 g of zinc carbonate putting both of them </em><em>in one stoppered container and labeled solid E</em></li>
</ol>

