CHM112 Home Page | Reference Materials | Homework Assignments | Lectures | Exams & Quizzes | Grades | Study Aids | URI Home Page |

Problem 13.38.

A first order reaction, A
products, has a rate of reaction of 0.00250 M s^{–1} when [A] =
0.484 M. (**a**) What is the rate constant, *k*, for this reaction? (**b**) Does t_{3/4}
depend on the initial concentration? Does t_{4/5}? Explain.

(**a**) For a first order reaction, Rate = *k*[A]. Since the rate and concentration
are known, solving the equation for *k* gives the required answer.
*k* = Rate/[A] = 0.00250 M s^{–1}/0.0484 M = 5.17 ×
10^{–3} s^{–1}.

(**b**) Neither t_{3/4} nor t_{4/5} depend upon intial
concentration because this is a first order reaction, which means that the time associated reaction is simply related to the rate
constant.