(a)(i) What is meant by the rate of a chemical reaction?

(ii) Explain in terms of the vision theory, the effect of temperature increase on reaction rate.

(b) When hydrogen peroxide is exposed to air, it decomposes

(i) Write an equation for the reaction.

(ii) Outline an experiment to illustrate that effect of a named catalyst on the rate of decomposition.

(iii) Sketch an energy profile diagram to show the effect of the catalyst on the reaction rate, given that the reaction is exothermic.

(c)(i) Explain why enthalpy data alone cannot be used to predict whether a reaction can occur spontaneously or not.

(a)(i) List four characteristic properties of transition metals

(ii) Name two metals that can be extracted from their ore by electrolysis.

(b)(i) Determine the oxidation number of chromium in Cr\(_2\)O\(^{2-}_{7}\)

(ii) State the colour observed on adding a few drops of dilute tetraoxosulphate (VI) acid to the system representedby the following equation: Cr\(_2\)O\(^{2-}_{7(aq)}\) + H\(_2O_{(l)}\) \(\rightleftharpoons\) 2CrO\(^{2-}_{4(aq)}\) + 2H\(^+_{(aq)}\). Explain your answer.

(c)(i) State and explain what would be observed if hydrogen sulphide gas were bubbled into acidified K\(_2\)Cr\(_2\)O\(_7\). Write an equation for the reaction.

(ii) What precaution should be taken to avoid excessive exposure to hydrogen sulphide gas while it is being generated in the laboratory?

(a) State;

(i) One advantage:

(ii) One disadvantage of evaporation of salt solutions to dryness over crystallization.

(b)(i) List two normal salts which when dissolved in pure water are acidic to litmus

(ii) Mention the phenomenon that accounts for the behaviour of the salts in (b)(i) above.

(c)(i) Outline a suitable laboratory method for separating a mixture of glucose and starch.

(i) Give two chemical tests that would enable you to identify three solids suspected to be glucose, sucrose and starch.

You are provided with two aqueous solutions labelled C and D. Carry out the following exercises on them. Record your observations and identify any gases evolved. State the condition you draw from the result of each test.

(a)(i) Mix C and D in a beaker thoroughly.

(ii) Filter the mixture. Keep both the residue and the filtrate.

(b)(i) To about 5cm\(^3\) of the filtrate, add barium chloride solution, followed by excess dilute hydrochloric acid in a boiling tube. Divide the resulting solution into two portions.

(c)(i) To the first portion of the solution from (b)(ii) above, add sodium hydroxide solution in excess.

(ii) To the second portion of the solution from (b)(ii) above, add aqueous ammonia in drops until it is in excess.

A solution containing 0.095 mol. dm\(^{-3}\) of trioxonitrate (V) acid. Solution B contains 13.50g of X\(_2\)CO\(_3\).10H\(_2\)O per dm\(^3\)

(a) Put A in the burette and titrate with 20cm\(^3\) or 25cm\(^3\) portions of B using methyl orange as an indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average volume of A used.

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

(i) Concentration of B in mol. dm\(^3\)

(ii) molar mass of X\(_2\)CO\(_3\).10H\(_2\)O

(iii) percentage by mass of X in X\(_2\)CO\(_3\).10H\(_3\)O. The equation for the reaction is X\(_2\)CO\(_3\) + 2HNO\(_3{(aq)}\) \(\to\) 2XNO\(_{3(aq)}\) + CO\(_{2(g)}\) + 11H\(_2\)O\(_{(l)}\) [H = 1, C = 12, O = 16]

(c) Give the reason for the following:
(i) using just a small quantity of the indicator during acid-base titrations.

(ii) obtaining at least two sets of readings for titration experiment.