The kinetics of a gas phase reaction of the form A → Products results in a rate constant of 1.308 M⁻¹ s⁻¹. For this reaction, the initial concentration of A is 0.155 M. What is the concentration of A after 0.385 seconds?

Explanation:

Hello,

In this case, given the rate constant, we infer this is about a second order reaction, whose equation is:

Thus, by integration we obtain:

Hence, we solve for the final concentration after 0.385 s:

Best regards.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.