THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA CERTIFICATE OF SECONDARY EDUCATION EXAMINATION 

032/1 CHEMISTRY 1

(For Both School and Private Candidates)

 Time: 3 Hours Thursday, 08^th November 2018 a.m.

Instructions

1. This paper consists of sections A, B and C with a total of thirteen (13) questions.
2. Answer all questions in this paper.
3. Calculators, cellular phones and any unauthorized materials are not allowed in the examination room.
4. Write your Examination Number on every page of your answer booklet(s).
5. The following constants may be used. Atomic masses:

 H 1, C = 12, 0=16, N = 14, Cu = 64,  Pb = 108. vogadros number = 6.02 x 10²³.

GMV at s.t.p = 22.4 dm³.

1 Faraday = 96,500 coulombs.

Standard pressure = 760 mm Hg.

Standard temperature = 273 K.

1 litre = 1 dm³ = 1000 cm³.

SECTION A (20 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 beside the item number.

 (i) Which of the following is an agricultural chemical products made by the application of chemistry?

1. Drugs 
2. Pesticides 
3. Clothes 
4. Yeasts 
5. Cement.

 (ii) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?

1.  2000 C  
2. 1000 C 
3.  200 C 
4.  0.20 C 
5.  7686 C.

(iii) Substance X liberates chlorine gas from acidified potassium chloride. The behaviour of X is described as:

1.  an oxidising agent    
2.  an oxidising and reducing agent
3.  catalyst   
4.  a reducing agent
5.  bleaching agent.

(iv) Which carbonate is the most stable to heat?

1.  Calcium carbonate   
2.  Copper (II) carbonate
3.  Lead (II) carbonate 
4.  Zinc carbonate 
5. .Iron (II) carbonate.

(v)  Aluminium does not react with water and does not corrode much in air because

1.  it is below hydrogen in the reactivity series
2.  it forms a stable carbonate which prevents reactions
3.  the metal is covered with a protective coating of an oxide 
4.  aluminium ions have positive charges
5.  it is very stable.

(vi) Which of the following compounds does NOT belong to the alkenes homologous series?

1.  C₂H₄ 
2.  C₃H₆  
3.  C₄H ₈ 
4.  C₅H₁₀ 
5.  C₆H ₁₄.

(vii) In the following equilibrium equation, 2S0_2(g) +O_2(g)  2S0₃ The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?

1.  Increasing temperature
2.  Decreasing temperature
3.  Decreasing sulphur trioxide concentration 
4. Decreasing pressure 
5. Adding a catalyst.

(viii) When a burning fuel produces blue color it means there is

1. adequate supply of oxygen with production of soot.
2. inadequate supply of oxygen without production of soot. 
3. inadequate supply of oxygen with production of soot.
4.  adequate supply of oxygen with production of less heat.
5.  adequate supply of oxygen with production of more heat.

(ix)  Which of the following equations represents the combustion of methane with the products collected at 120^oC?

1.  CH4(l) +2O2(g) ?CO2(g) + 2H2O(l)
2.  CH4(g) +2O2(l) ?CO2(s) + 2H2O(l)
3.  CH4(g) +2O2(g) ?CO2(g) + 2H2O(g)
4.  CH4(l) +2O2(l) ?CO2(l) + 2H2O(g)
5.  CH4(l) +2O2(g) ?CO2(g) + 2H2O(g)

   (x) Which of these can be reduced when heated with carbon?

1.  Aluminium  
2. Calcium carbonate
3. Iron (III) oxide 
4. Magnesium oxide 
5.  Sodium oxide.