Chapter 15, Problem 98E

The evaporation of a 120-nm film of n-pentane from a single crystal of aluminum oxide is zero order with a rate constant of $\text{1}.\text{92}\times \text{1}{0}^{\text{13}}$ molecules/cm². s at 120 K.

a. If the initial surface coverage is $\text{8}.\text{9}\times \text{1}{0}^{\text{16}}$ molecules/cm², how long will it take for one-half of the film to evaporate?
b. What fraction of the film is left after 10 s? Assume the same initial coverage as in part a.