THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA

CERTIFICATE OF SECONDARY EDUCATION EXAMINATION

032/1CHEMISTRY 1

(For Both School and Private Candidates)

Duration: 3 Hours Year: 2025

Instructions

1. This paper consists of sections A, B and C with a total of eleven (11) questions.
2. Answer all questions in sections A and B and two (2) questions from section C.
3. Section A carries sixteen (16) marks, section B fifty four (54) marks and section C thirty (30) marks.
4. Communication devices and any unauthorized materials are not allowed in the examination room.
5. Write your Examination Number on every page of your answer booklet(s).
6. All writing must be in blue/black ink except diagrams which must be drawn in pencil.
7. Non-programmable calculators may be used.
8. The following constants may be used.

• Atomic masses: H = 1, C = 12, Cl = 35.5, Zn = 65.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) – (x), choose the correct answer from the given alternatives and write its letter in the answer booklet provided.

(i) Which relationship supports the existence of water in three states of matter?

1. Ice → gas → solid, Solid → gas → ice
2. Liquid → ice → gas, Gas → ice → liquid
3. Gas → ice → liquid, Liquid → ice → gas
4. Ice → gas → liquid, Liquid → gas → ice
5. Ice → liquid → gas, Gas → liquid → ice

(ii) Which one is the molecular formula of a hydrocarbon having 20% hydrogen and vapour density of 15?

1. CHâ‚„
2. H₃C
3. H₆C₂
4. C₂H₆
5. C₃H₆

(iii) A chemical prepared hydrogen gas by mixing zinc granules with dilute hydrochloric acid. Which one of the following is correct about zinc reaction?

1. It is oxidized
2. It is an oxidizing agent
3. It undergoes both oxidation and reduction
4. It is reduced
5. It undergoes decomposition

(iv) A student exposed anhydrous copper(II) sulphate crystals in a watch glass over a whole night. In the next morning, the colour of copper(II) sulphate changed from L to M. Which pair represents the colours of L and M?

1. L-green and M-blue
2. L-blue and M-green
3. L-white and M-blue
4. L-blue and M-green
5. L-white and M-green

(v) Suppose a truck carrying flammable gas gets an accident and unfortunately fire breaks out. How will you extinguish the fire?

1. By using water and foam extinguisher.
2. By using dry powder and carbon dioxide extinguisher.
3. By using dry powder extinguisher and water.
4. By using wet chemical extinguisher and foam extinguisher.
5. By using water and carbon dioxide extinguisher.

(vi) Why is methane used as a source of fuel at homes and industries?

1. It burns in air to give out energy
2. It burns in air to give out water vapour
3. It burns in air to absorb energy
4. It burns in air to absorb water vapour
5. It burns in air to give out carbon dioxide

(vii) Why is it essential to allow the first supply of oxygen gas to escape during laboratory preparation of oxygen?

1. The gas jar contains impurities
2. The gas jar contains hydrogen peroxide
3. The gas jar contains some air in it
4. The gas jar is wet
5. The gas jar does not have a lid

(viii) A mass of zinc metal weighing 90 g was reacted with hydrochloric acid. The reaction stopped after 7 minutes, 17.5 g of zinc remained unreacted. How many moles of hydrochloric acid reacted with zinc?

1. 1.13 moles
2. 2.25 moles
3. 3.33 moles
4. 4.43 moles
5. 5.53 moles

(ix) Why is wind said to be the promising source of energy for the future?

1. It does not produce harmful gases.
2. It can easily be stored.
3. It is harnessed without chemical reaction.
4. It is a renewable source of energy.
5. It is the cheapest source.

(x) Why is calcium oxide useful during preparation of ammonia?

1. It removes water from the reaction.
2. It prevents the removal of water in the reaction.
3. It removes nitrogen gas from the reaction.
4. It prevents the loss of nitrogen from the reaction.
5. It increases the production of ammonia.