At 700 K, the rate constant for the following reaction is 6.2 *10^-4 min^-1. How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

Question

Quizplus · Accepted Answer

This is a first-order reaction, so the fraction of cyclopropane that remains after time t is given by N/N0 = e^-kt, where N/N0 is the fraction remaining, k is the rate constant, and t is time. We are given k, and we want to find t such that N/N0 = 0.2. Taking the natural logarithm of both sides gives: ln(0.2) = -kt. Rearranging gives t = -ln(0.2)/k. Substituting in k gives t = 360 min.

At 700 K, the Rate Constant for the Following Reaction