THE UNITED REPUBLIC OF TANZANIA MINISTRY OF EDUCATION AND VOCATIONAL TRAINING

FORM TWO SECONDARY EDUCATION EXAMINATION, 2009

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.

SECTION A

1. Write down the letter of the correct answer against each question.

(i)The fixed volume (20 cm³) of distilled water in the laboratory can be measured by using:

1. Beaker 
2. Burette
3. Pipette
4. Small measuring cylinder

(ii) Domestic utensils made of iron undergo rusting when exposed to:

1. Air and fire 
2. Air and oil
3. Air and water
4. Air and soil

(iii) The source of energy which when used can be made to be put into use again is known as:

1. Fuel 
2. Non-renewable energy
3. Renewable energy
4. Solar energy

(iv) A student who gets burnt accidentally in the chemistry laboratory would be given one of the following as first aid:

1. Antibiotic solution 
2. Nitric acid
3. Petroleum jelly
4. Potassium permanganate

(v) The chloride ion (Cl^-) differs from chlorine atom because chloride ion has:

1. Less electrons 
2. Less protons
3. More electrons 
4. More protons

(vi) The percentage by mass of nitrogen in (NH₄)₂CO₃ is:

1. 28.0 
2. 29.1
3. 37.5 
4. 96.0

(vii) The elements which are found in group VIII of the periodic table are known as:

1. Metals
2. Noble gases
3. Non-metals
4. Right elements

(viii) Isotopes are atoms which have:

1. Different mass number
2. Different number of electrons
3. Different number of protons
4. The same number of neutrons

(ix) The process used to separate a mixture of salt and water is:

1. Evaporation
2. Filtration
3. Simple distillation 
4. Sublimation

(x) Which of the following chemical species have the same number of electrons?

1. Cl, Be, He and O^2-
2. K⁺ , Ca²⁺ , Cl^- and Ar
3. Na⁺ , Mg²⁺ , C1³ and Ar
4. O^2- , F^- , S^2- and Cl^-

SECTION B

2. You are provided with two lists, A and B. Choose a word(s) from list B which matches the statement or phrase in list A.

3. (a) For each of the following classes of fire, state the burning material(s)

(i) Class A fire

(ii) Class B fire

(iii) Class C fire

(b) Fire can be prevented by (Mention four)

4. Use the following information about elements F, G, L, M and J shown in the Table below to answer the questions that follow:

(a) (i) Write down the electrons configuration of elements F, G, L and J.

(ii) How many neutrons are present in element G?

(b) Write the chemical symbols for the following elements:

(i) Silver

(ii) Lead

(iii) Tin

5. (a) State the meaning of apparatus.

(b) Draw and state one function for each of the following laboratory apparatus:

6. Oxygen is obtained by heating a metal chlorate in the presence of a catalyst.

(a) Write down the name of the:

(i) Metal chlorate used

(ii) The product formed other than oxygen

(b) Write the:

(i) Formula and the IUPAC name of the catalyst used. 

(ii) Word equation for this reaction.

(c) Draw a large and well labelled diagram for this laboratory preparation of oxygen.

7. (a) Define the term "chemical formula".

(b) Write down the chemical formula of the following compounds:

(i) Sodium carbonate ten water

(ii) Calcium hydroxide

(iii) Sulphuric acid

(c) Give the IUPAC names for each of the following compounds: 

(i) CU₂O

(ii) Na₂SO₄

(iii) NH₄NO₃

(iv) Fe₂O₃ 

(v) H₂O

8. (a) What is air?

(b) Mention the composition of air with their percentage composition:

(c) Give four reasons why air is a mixture.

9. Study the following diagram carefully and then answer the questions that follow:

(a) What is the name given to the arrangement of electrons around the nucleus?

(b) What is the name of the layers in which the electrons are arranged?

(c) If each layer can hold a maximum number of electrons given by formula 2n², what does "n" represent?

(d) By using the formula presented in Cc) above, calculate the number of electrons in: 

(i) K - Layer

(ii) L - Layer

(iii) M - Layer

(iv) N - Layer

10. (a) Give the method used to separate the following mixtures:

(i) Kerosene and water

(ii) Alcohol (ethanol) and water

(iii)Iron filings and sand

(b) Water is a chemical compound. Give four reasons to support this fact.