INSTRUCTIONS
Answer ALL questions.
Q1. (a) Explain the meaning of the following terms as used in chemical kinetics:
(i) Rate of reaction
(ii) Order of reaction
(iii) Molecularity of a reaction
(iv) Mechanism of a reaction
(v) Branching chain reaction [10 marks]
(b) Derive the kinetic equation for a second order reaction in a single substance and show
that the half-life is independent of the initial reactant concentration.
A + A → products [10 marks]
Q2. (a) Give an expression of the Arrhenius kinetic equation and explain what the different terms
represent. [5 marks]
(b) For the decomposition of nitrogen IV Oxide
2NO2(g) → 2NO(g) + O2(g)
the specific rate constant K, was determined to be 0.522mols
-1 at 319o
c and 1.700mol-1

LS-1 at 354o
c.
Determine the activation energy between these two temperatures. [5 marks]
Q3. (a) List the methods available for the determination of the order of a chemical reaction.
[4 marks]

The decomposition of a compound in solution gave the following data at 57.4o
c.
Initial concentration (moldm-3) 1.10 2.48
t½ sec (Half-life) 885 174
Calculate the value of the order of the reaction and the specific rate constant.
[6 marks]
Q4. (a) Derive the kinetic equation for a first order reaction. [10 marks]
(b) At 500o
c a certain compound rearranges to B by a first order process. The rate constant
for this rearrangement is 6.7 x 10-4S
-1
.
If the initial concentration of A is 0.05M,
(i) What will be the molarity of A after 30 minutes? [5 marks]
(ii) How many minutes will it take for the concentration of A to drop to 0.01M?
[5 marks]
(c) Write the rate Law expressions for the following reactions:
(i) A + B → C + D
(ii) 2A → B + C
(iii) 2(g)(g)
2NO2(g)  O 2NO
(iv) A + A → products
(v) 3c → products [10 marks]