Student's Assessment Number .....

THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA
FORM TWO NATIONAL ASSESSMENT

032 CHEMISTRY

 Time: 2:30 Hours   Year: 2021 

Instructions

1. This paper consists of sections A and B with a total of ten (10) questions.
2. Answer all questions in the spaces provided.
3. Section A carries twenty (20) marks and section B carries eighty (80) marks.
4. All writing must be in black or blue ink except diagrams which must be in pencil.
5. Cellular phones and any unauthorized materials are not allowed in the assessment room.
6. Write your Assessment Number at the top right corner of every page.
7. The following atomic masses may be used: H = 1, 0 = 16, S = 32, Ca = 40, Na = 23.

SECTION A (20 Marks)
Answer all questions in this section.

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

(i) Which particles contribute the net charge inside the nucleus of an atom?

1. Protons 
2. Neutrons
3. Electrons
4. Nucleons

(ii) Which of the following is not a man-made product of applying chemistry'?

1. Fertilizer 
2. Milk
3. Sugar
4. Vaccines

(iii) How is the amount of air entering in the Bunsen burner controlled?

1. By adjusting the opening of the barrel.
2. By adjusting the opening of the collar. 
3. By adjusting the opening of the jet. 
4. By adjusting the opening of the base.

(iv) How do the chemists refer to a mixture of milk and water?

1. Emulsion 
2. Suspension
3. Miscible solution 
4. Immiscible solution

(v) Why is it necessary to boil drinking water?

1. To remove oxygen.
2. To remove impurities.
3. To make it tasteless. 
4. To kill micro-organisms.

(vi) Which of the following indicates a pair of isotopes? 

1. ⁴⁰₂₀X and ⁴⁰₁₈X
2. ³⁹₁₉X and ⁴⁰₂₀X
3. ¹²₆X and ¹²₆X
4. ³⁵₁₇X and ³⁷₁₇X

(vii) Which of the following are the products of the reaction of sodium metal with water?

1. Sodium oxide and hydrogen gas. 
2. Sodium hydroxide and water.
3. Sodium oxide and water vapour.
4. Sodium hydroxide and hydrogen gas.

(viii) !low does the covalent bond form?

1. By combining opposite charged atoms.
2. By loss of electrons between ions.
3. By sharing of valence electrons.
4. By force of attraction of atoms.

(ix) flow can one prevent rusting in fragile instruments like cameras?

1. By using silica gel.
2. By using ethanol. 
3. By galvanization.
4. By using oil.

(x) What is the maximum number of electrons in the innermost shell of an atom?

1. 3 
2. 8
3. 2 
4. 1