When chlorine is passed through a sample of water, the pH of the water sample would be

• A.< 7
• B. > 7
• C. = 7
• D. 0

The law of definite proportions states that

• A. pure samples of the same compound contain the same elements combined in the same proportion by mass
• B. pure samples of substances are in the same proportion by mass
• C. chemical compounds are pure because they contain the same elements
• D. matter can neither be created nor destroyed.

How many atoms are contained in 0.2moles of nitrogen? [NA=6.02×10²³]

• A. 1.20×10²³
• B. 2.41×10²³
• C. 3.62×10²³
• D. 4.82×10²³

Which of the following methods can be used to seperate blood cells from plasma?

• A. Centrifugation
• B. Filtration
• C. Chromatography
• D. Distillation

An acidic salt has

• A. double anions in its aqueous solution
• B. a single cation in its aqueous solution
• C. hydrogen ions in its aqueous solution
• D. hydrogen atoms in its aqueous solution

The strength of metallic bonds depends on the

• A. charge density of the atoms
• B. ductility of the metal
• C. number of valence electrons
• D. total number of electrons in the atom

Which of the following organic compounds can undergo both addition and substitution reactions?

• A. Pentane
• B. Benzene
• C. Propane
• D. Hexane

The empirical formula of a compound containing 0.067mol Cu and 0.066mol O is [Cu = 63.5, O = 16]

• A. Cu₂O
• B. CuO
• C. CuO₂
• D. CuO₄

(a) Outline the procedures for the treatment of water for town supply.

(b) (i) Statetwo main impurities present in bauxite.

(ii) Giveone reason why bauxite is usually preferred as the ore for the extraction of aluminium.

(iii) Outline the manufacture of aluminium form purified bauxite.

(c) (i) Explainbriefly the termfine chemical industry.

(ii) Statetwo differences between afine chemical and a heavy chemical.

(d) (i) Write a balanced chemical equation for the combustion of coal.

(ii) If 5.4 g of coal is burnt completely, calculate the amount of oxygen measured at s.t.p. that would be required for the combustion.

[C = 12.0, O = 16.0, Molar volume of a gas at s.t.p. = 22.4 dm\(^3\)]

(e) Nametwo substances which can be used as electrodes during the electrolysis of acidified water.

Which of the following statements best explains the difference between a gas and a vapour?

• A. Unlike gases, vapours are liquids at room temperature
• B. Unlike gases, vapour can easily be condensed into liquids
• C. Unlike gases, vapour is readily converted into solids
• D. Vapours are generally denser than gases