(a) Write a balanced chemical equation for each of the following reactions:

(i) ammonia gas with copper(II) oxide;

(ii) ammonia gas with oxygen gas;

(iii) aqueous potassium iodide with chlorine gas;

(iv) iron with dilute tetraoxosulphate (VI) acid;

(v) aqueous lead(II) trioxonitrate (V) with hydrogen chloride gas.

b(i) Describe briefly the process involved in the extraction of tin from tin ore.

(ii) Mention three uses of hydrogen.

(iii) State two physical properties of hydrogen.

(c) State the class of oxide to which each of the following compounds belong:

(i) Na\(_2\)O;  (ii) ZnO; (iii)SO\(_2\); (iv) CO\(_2\); (v) N\(_2\)O. 

a(i) Write the chemical formula of alumina.

 (ii) In the extraction of aluminium, state one compound that is used;

  I. to obtain alumina from Bauxite

II. as solvent for alumina.

(iii) Name the electrodes used in the extraction of aluminium.

(iv) Give one reason why the extraction of aluminium is expensive.

(v) In the extraction of aluminium:

  I. name the substance liberated at the anode;

 II. write the equation for the reaction that leads to decrease in the size of the anode.

b(i) Give two ions that cause hardness of water.

 (ii) State two advantages and two disadvantages of hard water.

c(i) What is meant by destructive distillation of coal?

 (ii) Name four products obtained from the destructive distillation of coal.

d(i) Name two gases which can be used to demonstrate the fountain experiment.

(ii) Give the reason why the gases named in 5d(i) are used.

ALTERNATIVE TO PRACTICAL A

A  is a solution of KMnO\(_4\) containing 0.020 moldm\(^{-3}\). B is a solution of Fe\(^{2+}\) obtained by dissolving 3.8 g of iron granules in 250 cm\(^3\) of solution.

(a)Put A in the burette. Pipette 20.0 cm\(^3\) or 25 cm\(^3\) of B into a conical flask and add 10 cm\(^3\) of H\(_2\)SO\(_4\). Titrate it with A.

     Repeat the titration to obtain concordant titre values. Tabulate your result and calculate the average volume of A used. 

     MnO\(_4\)\(^-\)\(_{(aq)}\) +  5Fe\(^{2+}\)\(_{(aq)}\)  +  8H\(^+\)\(_{(aq)}\) → Mn\(^{2+}\)\(_{(aq)}\)  + Fe\(^{3+}\)\(_{(aq)}\) +  4H\(_2\)O\(_{(l)}\)                 

[ KMnO\(_4\) = 158.0, Fe = 56.0 ]

(b) From your results and information provided, calculate the:

(i) concentration of B in moldm\(^{-3}\)

(ii)concentration of B in gdm\(^{-3}\)

(iii) mass of Fe\(^{2+}\) in 250 cm\(^3\) of B.

(iv) percentage of Fe\(^{2+}\) in the granules.

C is a mixture of two simple inorganic salts, one of which is a sodium salt.

Perform the following exercises on C. Record your observation and identify any gas(es) evolved. State the conclusions you draw from the results of each test.

(a) Put all of C into a test tube and add about 10 cm\(^3\) of distilled water and shake.

b(i) Put about 2 cm\(^3\) of the filtrate into a boiling tube and heat strongly.

  (ii) Put half of the residue into a test tube and add dil. HCl.

  (iii) To about 2 cm\(^3\) of the clear solution from b(ii), add aqueous NaOH in drops, then in excess.

  (iv) To another 2 cm\(^3\) of the clear solution from b(ii), add aqueous ammonia in drops, then in excess.

(a) Mention two gases that are soluble in water.

(b) Name two apparatus that could be used to measure 9.50 cm\(^3\) of a solution accurately.

(c) What is the use of a fume cupboard in the laboratory?

(d) Name three personal protective equipment that are used in the laboratory.