(a)(i) List three observable changes that take place when a dilute solution of copper (II) chloride is electrolysed using platinum electrodes. Stage III

(ii) Calculate the quantity of electricity used during electrolysis when a current of 0.21 ampere flows for 2 hours.

(iii) State what is meant by the term preferential discharge of ions in electrolysis

(iv) Give one factor which influences the preferentia! discharge of ions during electrolysis.

(v) State one Q difference between-a conductor and an electrolyte.

(b) Consider the reaction represented by the equation below: Na\(_2\)S\(_2\)O\(_{3(aq)}\) + 2HCI\(_{(aq)}\) \(\to\) 2NaCI\(_{(aq)}\) + H\(_2\)O\(_{(l)}\) + SO\(_{2(g)}\) + S\(_{(s)}\)

(i) List two factors that can affect the rate of this reaction.

(i) Which of the products can be readily used to measure the rate of the reaction. Give a reason for your answer.

(iii) Name two instruments that can be used to measure factors in (b)(i) above.

(c)(i) State the reasons for regarding rusting and burning as oxidation processes.

(ii) I. Write the balanced half equations for the following redox reaction: Mg\(_{(s)}\) + Fe\(^{2+}_{(aq)}\)  ----> Mg\(^{2+}_{(aq)}\) + Fe\(_{(s)}\)

II. Which of the reactants is the oxidizing agent?

Ill. State the change in the oxidation number of the oxidizing agent.

(d)(i) State one ore from which each of the following metals can be extracted. I. Tin II. Iron (ii) List two uses of copper (iii) Name one alloy of tin.

(a)(i) State the two types of hardness in water.

(ii) Name a salt that causes each type of hardness.

(ii) Write a balanced equation for the removal of each type of hardness.

(iv) State one effect of hard water on soap.

(b)(i) State whether the pH of each of the following is less than, equal to, or greater than 7.

I. Glucose solution II. Chlroine water III. Lime water IV. Sour milk

(ii) Give the difference between the following compounds: I. an acidic oxide and an amphoteric oxide; II. concentrated acid and a dilute acid; Ill. a normal salt and an acid salt

(c)(i) Iron reacts with H\(_2\)SO\(_4\) according to the equation: Fe\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) ---> FeSO\(_{4(aq)}\) + H\(_{2(g)}\)

Calculate the mass of FeSO\(_4\) that would be produced by 0.5 mole of Fe. [H = 1, S = 32, Fe = 56]

(ii) List two allotropes of sulphur

(d)(i) State what would La observed when a damp starch-iodide paper is dropped into a gas jar of chloride

(ii) Explain your ansv.er in (d)(i) above.

(iii) State the products formed when ammonia reacts with excess chlorine.

(i) Name two amorphous forms of carbon

(ii) State the reason why graphite is a lubricant but diamond is not.

(iii) Draw and label a diagram for the laboratory preparation of a dry sample of carbon (IV) oxide.

(b)(i) Give one example of the following: I. Soil pollutant; II. Water pollutant; III. Air pollutant.

(ii) State the major use of sulphur (IV) oxide in a chemical industry.

(c)(i) Explain in terms of the kinetic theory why petrol is volatile

(ii) State two criteria for determining the purity of a substance.

(iii) Mention one use of each of the following gases: I. Krypton; II. Argon

(d)(i) When zinc metal was added to aqueous copper (I) tetraoxosulphate (VI), the solution turned colourless. I. Name the compound in the colourless solution. II. Write the ionic equation for the reaction. Ill. State what would be observed when a few drops of sodium hydroxide solution is added to a portion of the colourless solution.

(ii) Calculate the volume of CO\(_2\) produced when 5.3g of Na\(_2\)CO\(_3\) reacted with excess HNO\(_{3(aq)}\) + Na\(_2\)CO\(_3\) + 2HNO\(_{3(aq)}\) \(\to\) 2NaNO\(_{3(aq)}\) + CO\(_{2(g)}\) + H\(_2\)O\(_{(l)}\) [H = 1, C = 12, N = 14, O = 16, Na = 23, 1 mole of a gas occupies 22.4 dm\(^3\) at s.t.p.]

(a) State what would be observed when:

(i) Chlorine is passed through a freshly prepared solution of FeCl\(_2\).

(ii) SO\(_2\) is bubbled into a solution of FeCl\(_3\);

(iii) A few drops of water Is added to sodium hydroxide pellets in a test tube;

(iv) Dilute H\(_2\)SO\(_4\) is added to CaCO\(_{3(s)}\)

(b) Three test tubes contain solutions of SO\(_3^{2-}\), CO\(^{2-}_3\) and SO\(_4^{2-}\) respectively. Describe one chemical method that you would use to identify the solution containing SO\(_4^{2-}\) 

(c)(i) Draw and label a diagram to illustrate the separation of a mixture of petrol and water

(ii) Which of the following will dissolve faster? 10g of NaOH pellets in 100 cm\(^3\) of water; 10g of NaOH powder in 50 cm\(^3\) of water. Give the reason for your answer.

Credit will be given for strict adherence to instructions, for observations precisely recorded, and for accurate inferences. All tests, observations, and inferences must be clearly entered in your answer book, in ink, at the time they are made.

C Is an inorganic salt. D is an organic compound. Carry out the following exercises on C and D. Record your observations and identify any gases evolved. State the conclusion you draw from the result of each test.

(a) (i) Put C in a test tube and add about 10 cm\(^3\) of distilled water. Stir well.

(ii) Divide the resulting solution into two portions. To the first portion add sodium hydroxide solution in drops and then in excess.

(iii) To the second portion add dilute trioxonitrate (V) acid. Then add silver trioxonitrate (V) solution followed by aqueous ammonia in excess. tube and odd about 2- 5 cm\(^3\) of 'Xn'.

(ii) Identify the functional group present in D.