(a)(i) State Graham's law of diffusion.

(ii) Consider the reaction represented by the following equation:

N\(_2\)O\(_{4(g)}\)  2NO\(_{2(g)}\)

Night yellow                           dark brown

State what would happen to the vapour density of N\(_2\)O\(_4\) as the temperature of the system is increased. If the system is cooled, would the gases become lighter or darker in colour? Explain your answer in each case.

(b) Explain the following observations:

(i) an inflated balloon that was left in the sun. burst after some time;

(ii) a pure sample of a liquid did not have a constant boiling point at the top and at the base of a high mountain

(c)(i) List two gaseous reducing agents

(ii) Write one equation each to illustrate the reducing property of the gases you listed in (c)(i) above.

(a)(i) List two uses of aluminium and state how each use is related to the properties of the element.

(ii) State the reason why aluminium oxide is said to be amphoteric.

(b) Calcium is extracted by the electrolysis of fused calcium chloride containing about one-sixth of its mass of calcium fluoride.

(i) Sketch and label the cell used for the extraction.

(ii) Write equations for the reactions at the electrodes.

(iii) State the role of the calcium fluoride in the extraction.

(c) W, X, Y and Z represent four metals which have the following properties: W does not react with cold water but it liberates hydrogen from steam; X is one of the products formed when its trioxonitrate (V) decomposes on strong heating; Z forms the oxide when heated in air and it displaces W from an aqueous solutions of a salt of W; Y tarnishes rapidly exposure and reacts vigorously with cold water. Use the information provided to deduce the order of reactivity of the metals.

State the atoms represented as shown below:

(a) State the relationship between the two atoms.

(b) What is the difference between them?

(c) Give two examples of elements which exhibit the phenomenon illustrated above.

(a)State three characteristics of a catalyst.

(b) Mention one manufacturing process in which each of the following metals is used as a catalyst:

(i) iron;

(ii) nickel;

(iii) platinum

(c) Give one example of an organic catalyst.

A colourless and odourless gas X burns in oxygen with a pale blue flame.

(a) Suggest two gases which X could be.

(b) Give one chemical test that could be used to confirm which of the two gases X is.