homework question

Question

A reactant decomposes with a half-life of 185 s when its initial concentration is 0.118 M. When the initial concentration is 0.799 M, this same reactant decomposes with the same half-life of 185 s.

What is the order of the reaction?

What is the value and unit of the rate constant of this reaction?

Answer 1

It is a first order reaction because for the first order reactions, the half life is independent of the initial concentration, when you changed the initial concentration from 0.118 to 0.799, the half life did not change.

k= 0.693/half life = 0.693/185 seconds = 0.0037459 Sec^-1