The rate constant for a certain reaction is k=8.90×10^−3 s^-1. If the initial reactant concentration was 0.400M, what will the concentration be after 13.0 minutes?

Answer 1

With unit for rate constant in s^-1, you know it is first order. Therefore, use the equation ln(No/N) = kt
You know No = 0.400M, solve for N, you know k and t.

Answer 2

0.000395