Question

Azomethane decomposes into nitrogen and ethane at elevated temperature:

H3C_N=N_CH3 _ N2 + C2H6
A chemist studying this reaction at 300ÁC begins an experiment with an azomethane concentration of 4.25 mM and obtains the following data:
Time(s) 100 150 200 250 300
[Azomethane] (mM) 3.29 2.90 2.55 2.25 1.98
Calculate the rate constant. Give an answer with concentration units of molarity and time units of seconds.

Answer 1

For a 1st order reaction:
In(n/n0)= -k * (time difference)
so k= - In (n/n0)/ (t/t0)
n is concentration at time t and n0 is the concentration at an earlier time t0.
where k is constant.