THE UNITED REPUBLIC OF TANZANIA MINISTRY OF EDUCATION AND VOCATIONAL TRAINING

FORM TWO SECONDARY EDUCATION EXAMINATION, 2007

0032 CHEMISTRY

TIME: 2 HOURS

INSTRUCTIONS

1. This paper consists of three sections A, B and C.

2. Answer all questions in spaces provided for each question.

3. Write your examination number on the top right hand corner of every page.

4. All writing must be done in “black or blue pen” except for the diagrams which must be in pencil.

5. Cellphones and calculators are not allowed in the examination room.

6. The following constants may be used:

Atomic masses: H = 1, C = 12, O = 16, and Na = 23.

This paper consists of 10 printed pages.

SECTION A (10 Marks)

1. Write down the letter corresponding to the most correct answer in the box provided for each question.

(i) When a chemist studies a substance, he/she is interested in its:

1. force of attraction
2. shape
3. smell
4. properties

(ii) When you melt a piece of iron, it undergoes:

1. sublimation
2. physical change
3. chemical change
4. combination

(iii) One isotope of an element has atomic number A and mass number M. How many neutrons are contained in the nucleus of its atom?

1. M
2. A
3. A – M
4. M – A

(iv) The total number of protons and neutrons in the nucleus of an atom is called:

1. valency number
2. atomic number
3. molecule number
4. mass number

(v) Hydrogen gas can be collected by downward delivery because:

1. it burns in air with a pop-sound
2. it is more soluble than air
3. it is lighter than air
4. it can fill balloons

(vi) The reaction that takes place when limestone CaCO₃ is heated in the laboratory can be described as:

1. combination
2. decomposition
3. replacement
4. double decomposition

(vii) Which of the following warning signs is likely to be found on the bottle containing petrol?

1. oxidant
2. flammable
3. corrosive
4. irritant

(viii) The process of chlorination in water treatment aims at:

1. killing micro-organisms
2. removing bad odours
3. forming suspension
4. syrup making

(ix) Oxidation may be defined as:

1. loss of hydrogen by a substance
2. gain of hydrogen by a substance
3. reaction in which oxygen is lost
4. reaction in which electrons are increased

(x) Which of the following sets of symbols represents isotopes: