Question

The following questions refer to the gas-phase decomposition of ethylene chloride. C2H5Cl ® products Experiment shows that the decomposition is first order. The following data show kinetics information for this reaction: Time (s) ln [C2H5Cl] (M) 1.0 –1.625 2.0 –1.735 What is the half-life time for this reaction?

Answer 1

Answer:

Half life = 6.3 seconds

Explanation:

C2H5Cl --> products

Experiment shows that the decomposition is first order.

Time (s) ln [C2H5Cl] (M)

1.0          –1.625

2.0         –1.735

The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction:

t1/2 = 0.693/k.

To obtain the rate constant, k, we use the integral rate equation;

ln[A] = ln[A]o - kt

kt = ln[A]o - ln[A]

k = (ln[A]o - ln[A]) / t

k =  [–1.625  - (–1.735)] / 1

k = –1.625 + 1.735

k = 0.11

Half life, t1/2 = 0.693/ 0.11

Half life = 6.3 seconds