CHAP. 9: CHEMICAL KINETICS [CONTENTS] 274
Obr.9.2:Time dependence of the reactants concentration for a first-order reaction of the type A→B.
The initial concentration of the reactant iscA0, the starting concentration of the product is zero.
Solution
We calculate the rate constant using equation (9.26)
k=
ln 2
τ 1 / 2
=
0. 693
693
= 0. 001 s−^1.
The concentration at timeτ= 5 min is calculated from relation (9.25)
cA= 0.1 exp (− 0. 001 ·300) = 0. 074 mol dm−^3.
9.2.3 Second-order reactions
We will deal with three types of second-order reactions:
a) Type
2 A→products. (9.27)