Question

A student wants to determine the rate constant of a first-order reaction. The initial concentration of reactant is 0.050 M and after 60 seconds, the concentration drops to 0.025 M. What is the rate constant of the reaction?

Answer 1

To determine the rate constant of a first-order reaction, we can use the integrated rate law for first-order reactions:ln [A]t / [A]0  = -ktwhere [A]t is the concentration of the reactant at time t, [A]0 is the initial concentration of the reactant, k is the rate constant, and t is the time.In this case, [A]0 = 0.050 M, [A]t = 0.025 M, and t = 60 seconds. We can plug these values into the equation and solve for k:ln 0.025 / 0.050  = -k * 60ln 0.5  = -60kk = -  ln 0.5  / 60 k  0.0116 sSo, the rate constant of the reaction is approximately 0.0116 s.