CHEMISTRY FORM 3 END TERM EXAMS PLUS ANSWERS FREE

ULTIMATE ACHIEVERS ACADEMY

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END OF TERM  EXAMINATION 

FORM THREE

CHEMISTRY

2 HOURS

Instructions to candidates:

1. Answer all questions in both section A and B.
2. All working must be clearly shown and, in the spaces provided.

FOR EXAMINER’S USE ONLY

Section	Maximum Score	Candidate’s Score
A	40
B	40
Grand Score	80

 

SECTION A                                                                                                               40MARKS

1. Distinguish between an element and a compound. (2 Mks)

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2. A compound has an empirical formula of C₂H₅ Given it has a R.M.M. of 90, determine its molecular formulae. (C=12, H=1, O=16)                                                 (2 Mks)

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3. Identify the particles responsible for electrical conductivity in each of the following. (3 Mks)
4. Molten sodium chloride

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1. Zinc metal

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1. Graphite

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4. The diagram below shows a set up used to investigate one of the conditions necessary for rusting.

 

 

 

 

 

 

 

1. Identify the conditions being investigated in the experiment. (1 Mk)

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1. State whether rusting occurred or Not. (1 Mk)

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1. Explain why rusting occurs faster near factories that emit gases such as CO₂, NO₂ and SO₂ into the atmosphere.                                                       (2 Mks)

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5. Explain why a reaction occurs between copper (ii) oxide and magnesium powder, but no reaction occurs between magnesium oxide and copper powder.                                           (2 Mks)

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6. The set-up below shows one of the methods used to separate a mixture of liquids P and Q

 

 

 

 

 

 

 

 

1. State two properties of the liquids P and Q that make it possible to separate using the above method.                                     (2 Mks)

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1. Name any other two methods that can be used to separate the mixture of liquids p and Q.

(2 mks)

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7. The diagram below shows arrangement of particles in the three state of matter in no particular order.

 

 

 

 

 

 

 

1. Which of the diagrams I, II and III represents;
2. Matter in the solid state. (1 Mks)

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1. Matter in the gaseous state. (1 Mk)

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• State in which matter has the highest kinetic energy. (1 Mk)

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8. The ratio of the rates if diffusion of gas X and gas y is 3:8. Given that 200 cm³of gas X diffuse through a porous plug in 75 seconds. How long would it take 160 cm³ of gas Y to diffuse under the same conditions?                                           (3 Mks)

 

 

 

 

 

8. Describe how you can prepare a dry sample of barium sulphate starting with Barium nitrate crystals. (3 Mks)

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9. Sodium carbonate can be obtained on large scale by manufacturing through the Solvay process.
10. Name two raw materials for this process. (2 Mks)

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1. Identify any other method that can be used to obtain sodium carbonate on large scale.

(1 Mk)

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• State one use of sodium carbonate. (1 Mk)

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10. Molten lead (ii) bromide was electrolyzed using carbon electrodes.
11. Name any other substance that can suitably be used as electrodes in place of carbon. (1 Mk)

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1. Name the product formed at the cathode. (1 Mk)

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1. Write the ionic equation of the reaction that occurred at the cathode. (1 Mk)

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11. The diagram below shows parts of a set-up to prepare and collect dry hydrogen gas.

 

 

 

 

1. Identify reagent N and drying agent K. (2 Mks)

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1. Complete the diagram to show how the dry hydrogen gas is collected.                                     (2 Mks)

 

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12. Using universal indicator, describe how you can determine the PH value of a given solution.

(2 Mks)

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1. State one advantage of universal indicator over other commercial indicators. (1 Mk)

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SECTION B

13. The grid below shows a section of the periodic table, the letters are not the actual chemical symbols.

 

 

1. Name the family into which element Q belongs to (1 Mk)

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1. Element E can be placed in group I or group VII. Explain why (2 Mks)

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1. What Name is given to the elements found in the shaded region W. (1 Mk)

 

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1. Which letter represents element with the highest melting point in group II. Give reasons

(2 Mks)

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1. Write the chemical formulae of the;
2. Sulphate of L (1 Mk)

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1. Nitrate of R (1 Mk)

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1. How does the following compare? Explain your answer
2. Reactivity of J and N. (2 Mks)

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1. Boilling point of the oxides of M and T.                         (2 Mks)

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14. In an experiment, 80 cm³ of 0.75 M hydrochloride acid were reacted with excess zinc carbonate to form solution W, Liquid R and gas T.
15. Identify solution W and gas T. (2 Mks)

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1. Write a chemical equation of the reaction that occurred. (1 Mk)

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1. Calculate the;
2. Number of moles of hydrochloric acid that reacted with the zinc carbonate. ( 2 Mks)

 

 

1. Number of moles of the Zinc carbonate that reacted with the acid (2 Mks)

 

 

• Mass of the Zinc carbonate that reacted with the acid. (Zn = 65, C= 12, O= 16)

(2 Mks)

 

 

 

1. Volume of gas T evolved at r.t.p. (1 Mole of gas at r.t.p. = 24 litres) (2 Mks)

 

 

15. (a). Name the following hydrocarbons                                           (3Mks)
16. CH₃CH₂CH₂CH₂CH_{3 ______________________________________}

 

 

1. CH₃CHCHCHCH_{2 ________________________________________}

 

Br        CH₃                               Br

• H –   C    –    C    –    C    =    C   –    C   –   H

 

 

H               CH₃                       H

 

1. The diagram below shows some reactions involving hydrocarbons.

 

 

 

 

 

 

1. Identify the following (5 Mks)

I – substance L

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II – Substance M

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III – Substance Q

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IV – Process P

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V – Process N

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1. Name two substances that can be used as catalysts during process W. (2 Mks)

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16. Nitrogen (iv) oxide is one of the oxides of nitrogen.
17. Name the other two oxides of nitrogen (2 Mks)

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1. Which of the oxides you have named in a(i) above relights a glowing splint. (1 Mk)

 

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1. Ammonia is a compound of nitrogen that can be obtained industrially by the Haber process;
2. Other than nitrogen, name the other raw material for this process. (1 Mk)

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1. Write a chemical equation of the reaction that occurs in the catalytic chamber to produce Ammonia. (1 Mk)

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• State one use of ammonia (1 Mk)

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1. When burning magnesium is lowered into a gas jar containing air magnesium oxide is one of the products formed. Name the other product that can possibly be formed. (1 mk)

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