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 : 2021

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 = 1, O =16, C =12, N = 14, Na =23, Ca = 40, Cl = 35.5, Pb= 207.

Avogadro's 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.

I litre 1 dm³ 1000 cm³

SECTION A ( 15 Marks)

Answer all questions in this section.

l. 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 among the following sets of materials can cause fire outbreak?

1. Oxygen, carbon dioxide and fuel
2. Oxygen, heat and fuel
3. Oxygen, heat and carbon dioxide
4. Oxygen, foam and fuel
5. Oxygen, heat and foam

(ii)What type of fire occurs in vapour air mixture over the surface of flammable liquids?

1. Class A        
2. Class B       
3. Class C
4. Class D 
5. Class E

(iii)Which one of the following processes is a chemical change?

1. Butter melts on warm toast
2. Water evaporates from the surface
3. Juice in a bottle freezes
4. Food scrap turns into compost
5. Wet cloth dries

(iv) The simplest formula of a compound formed when combining 36 g of magnesium and 14 g of nitrogen is:

1. MgN
2. Mg₂N
3. Mg₃N₂ 
4. MgN₂
5. Mg₄N₂

(v)What is the IUPAC name for H₂S0₄ ?

1. Sulphuric acid
2. Sulphuric (VI) acid
3. Hydrogen sulphate
4. Dihydrogen sulphate
5. Hydrogen tetrasulphate

(vi)     What type of chemical reaction is represented by the equation  Zn(s) + 2HCl(aq)  + H₂(g)?

1. Displacement reaction
2. Combination reaction
3. Precipitation reaction
4. Decomposition reaction
5. Redox reaction

(vii)   What does the random movement of pollen grains suspended in air demonstrates?

1. Matter is lighter in nature.
2. Matter is solid in nature.
3. Matter is particulate in nature.
4. Matter is gaseous in nature. 
5. Matter is wave in nature.

(viii)"Organic matter is among the components of soil." Which role does it play?

1. Improving water infiltration of the soil.
2. Accelerating break down of organic matter.
3. Reserving nutrients thus providing soil fertility.
4. Converting of nitrogen into nitrates.
5. Providing a room for organic material such as nylons.

(ix) Which of the following sets represents isotopes of an element?

1.       Z, and
2.  Z, and
3.    Z, and
4.  Z, and
5.  Z, and

 (x)What is to be considered when choosing the best method to extract a particular metal from its ore?

1. The metal 's economic value.
2. Its availability in an area.
3. The metal's ore impurities.
4. How it reacts with other materials. 
5. The metal's shininess.