Question

In general, to calculate the rate constant for a first order decomposition reaction, A ➞ products, given the time needed to decrease the initial concentration by one-half, which equation should be used?

a) [A]t = -kt + [A]0;

b) t1/2 = 1/(k [A]0);

c) Rate = k [A];

d) 1/[A]t = kt + 1/[A]0;

e) t1/2 = ln 2/k

I answered with the last answer, e, but it was marked as incorrect. What am I missing? Thank you!