THE UNITED REPUBLIC OF TANZANIA MINISTRY OF EDUCATION AND VOCATIONAL TRAINING

FORM TWO SECONDARY EDUCATION EXAMINATION, 2003

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

This section consists of multiple choice items (i) — (ii). You are required to answer all questions in this section.

1. Write down the letter of the most correct response for each question:

(i) Chemistry is one of the sciences which deals with:

1. Alkalinity and basicity of substances.
2. The study of body cells.
3. Composition, properties and behaviour of matter. 
4. Chemical changes.

(ii) 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

(iii) In the diagram T represents a:

1. Bunsen burner flame
2. Region of unburnt gas
3. Zone of complete combustion
4. Gas burning

(iv) The neutral point in that pH scale is:

1. 0.7 
2. 7
3. 6
4. 8.0

(v) If the element M in the group I combines with element X of group VI the formula of the compound formed is:

1. MX₂ 
2. MX₀
3. X₂M
4. M₂X

(vi) Group seven elements are known as:

1. Alkali metals
2. Transition metals
3. Alkaline earth metals
4. Halogens

(vii) The simplest ionic equation which summarizes the process of neutralization is:

1. H⁺ + Nao  → H₂O + Na
2. NaOH + CI  → NaCI
3. H⁺ + OH  → H₂O
4. Na⁺CI^-  → NaCI

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

1. K⁺, Ca²⁺ , Cl^- and Ar
2. Cl^-, Be and O^2-
3. O^2-, Mg²⁺
4. Na⁺, Mg²⁺ , Be^2- and Li

(ix) A pipette is used for:

1. Measuring distance of length
2. Measuring specific volume of liquids
3. Measuring volumes
4. Heating liquid

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

1. Killing micro-organisms
2. Syrup making
3. Forming suspension
4. Removing bad odours

SECTION B

2. You are provided with two lists, A and B. Choose a word(s) from list B which matches the statement in list A and write its letter against the appropriate statement in the space provided.

SECTION C

3. (a) What is matter?

(b) Mention three (3) states of matter.

(c) Write the names of the following process of changing matter from one state to another.

4. (a) Write the chemical symbols for the following:

(i) Lead

(ii) Potassium

(iii) Gold

(iv) Sodium

(v) Chlorine

(b) Write the formulae for the following compounds:

(i) Carbon tetrachloride

(ii) Magnesium oxide

(iii) Aluminum sulphate

(iv) Ammonia

(v) Nitrogen dioxide

(c) Write balanced equations for the following chemical reactions:

(i) Iron + Sulphate → iron sulphate

(ii) Decomposition of calcium carbonate

(iii) Magnesium hydroxide + hydrochloric →  Magnesium chloride + H₂O

(iv) Silver nitrate + Sodium Chloride →  Silver chloride + Sodium nitrate

(v) Potassium + Sulphuric acid →  Potassium Sulphate + hydrogen gas

5. (a) Define the term indicator.

(b) Name the colours of indicators when they are in acidic or alkaline solution.

(c) Find the oxidation state or number of the following underlined elements:

(i) Mg 

(ii) NO₃ 

(iii) SO^2-₄

(iv) Na₃PO₄

6. (a) Element A and B in the Periodic Table have atomic numbers 12 and 13 respectively.

(i) Which element has a higher ionization energy?

(ii) Of the two elements which one has smaller atoms?

(iii) Which type of bond forms when element A combines with chlorine?

(iv) Find the charge of atom A after the reaction in question (iii).

(b) Mention four methods of preventing rusting.

(c) Define the following:

(i) Acid

(ii) Base

7.(a) Which method would you use to separate each of the following mixtures?

(i) Water mixed with kerosene

(ii) Iron powder mixed with sand

(iii) Ammonium chloride crystals mixed with sodium chloride crystal 

(iv) Water mixed with alcohol

(b) Write three differences between a mixture and a compound.

8. Classify each of the following chemical equations as displacement, combination, neutralization, depositions or decomposition.

(i) BaC1_2(aq) + ZnSO_4(s) → BaSO_4(s) + ZnC1_2(aq) 

(ii) N_2(g) + H_2(g) →  2NH_3(g)

(iii) 2Na_(s) + 2HCl_(aq) →  2NH_3(g)

(iv) CaO + 2HCl →  CaCl + H₂O

(v) CuCO₃ → CuO + CO₂

(b) What is the use of the following apparatus?

(i) Sandbath

(ii) Dropper

(iii) Tripod stand

(iv) Pipette

(v) Desiccator

9. (a) Draw a well labelled diagram of preparation of hydrogen gas.

(b) What is the test of hydrogen gas? 

(c) State any three uses of hydrogen.

10. Define the term combustion.

(a) Write down three (3) examples of combustible substances.

(b) Explain why luminous flame is not used for heating.

(c) What do you understand by the following chemical warning terms?

(i) Explosive

(ii) Toxic

(iii) Flammable

(iv) Harmful