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 Year: 2020

Instructions

l. This paper consists of sections A, B and C with a total of fourteen (14) questions.

2.Answer all questions in sections A and B and one (1) question from section C.

3.Sections A and C carry fifteen (15) marks each and section B carries seventy (70) marks.

4.Cellular phones and any unauthorised materials are not allowed in the examination room.

5.Write your Examination Number on every page of your answer booklet(s).

6.The following constants may be used.

Atomic masses: H =l, C= 12, N=14, O= 16, Na = 23, S = 32, ca = 40, Cl = 35.5, cu = 64 Zn 65. 

Avogadro's number 6.02 x 10²³ 

GM V at s.t.p = 22.4 dm³ .

I Faraday = 96,500 coulombs.

Standard pressure = 760 mm Hg.

Standard temperature= 273 K.

I litre= I dm³ 1000 cm³.

SECTION A (15 Marks)

Answer all questions in this section.

For each of the items (i) - (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i) Which of the following pairs constitute the best methods for treating and purifying water?

1. Chlorination and aeration
2. Chlorination and decantation
3. Chlorination and filtration
4. Chlorination and sedimentation
5. Chlorination and distillation

(ii)A good fuel is the one which has

1. high speed of continuous energy supply.
2. high energy value supplied.
3. low carbon dioxide supplied.
4. high carbon dioxide production.
5. high content of non-combustible material.

(iii) A rapid chemical reaction that releases energy in form of light and heat is called 

1.  combustion.
2.  decomposition.
3.  displacement. 
4.  neutralization.
5.  precipitation.

(iv)Which one is the molecular formula for prop-I-yne?

1. C₃H₆ 
2.  CH₃CCH
3.  C₃H₄ 
4.  HCH₂CCH 
5.  CH₃CHCH₂

(v)Which of the following is not a component of the First Aid Kit?

1. Goggles 
2.  A pair of scissors
3.  Dropper 
4.  Gloves
5.  Razor blade

(vi)Which of the following is the correct sequence of the last two steps you should follow during the scientific procedure?

1. Hypothesis formulation and conclusion
2. Observation and problem identification
3. Experimentation and conclusion
4. Problem identification and hypothesis formulation
5.  Interpretation of data and conclusion.

(vii)Consider the following reagents:

1. H₂O₂
2. H₂O
3. MnO₄
4. .MnO₂

Which reagents are involved in the preparation of oxygen gas in the laboratory?

1. I and 2
2. 3 and 4
3. CI and 3
4. 2 and 3
5. I and 4

(viii)Why oxygen differs from other gases?

1. It neither burns nor support combustion.
2. It supports combustion but does not burn.
3. It burns but does not support combustion.
4. It burns and supports combustion.
5. It explodes and support combustion.

(ix)What is the best way of preparing hydrogen gas in the laboratory?

1. By reacting strong metals and dilute acids.
2. By reacting metals and acids.
3. By reacting moderate metals and concentrated acids.
4. By reacting moderate metals and dilute acids. 
5. By reacting strong metals and strong acids.

(x)What volume of hydrogen gas will be produced when 1.3 g of zinc granules react completely with excess dilute sulphuric acid at s.t.p?

1. 130 cm³  
2.  224 cm³
3.  440 cm³ 
4.  220 cm³
5.  448 cm³