Chapter 11, Problem 115IP

The decomposition of iodoethane in the gas phase proceeds according to the following equation:

${\text{C}}_{\text{2}}{\text{H}}_{\text{5}}\text{I}\left(g\right)\to {\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\left(g\right)+\text{HI}\left(g\right)$

At 660. K, k = 7.2 ×10⁻⁴ s^−l; at 720. K, k = 1.7 × 10⁻² s^−l. What is the value of the rate constant for this first-order decomposition at 325°C? If the initial pressure of iodoethane is 894 torr at 245°C, what is the pressure of iodoethane after three half-lives?