Chapter 12, Problem 13Q

For the reaction

${\text{O}}_{\text{2}}\left(g\right)\text{+2NO}\left(g\right)\to {\text{2NO}}_{\text{2}}\left(g\right)$

the observed rate law is

$\text{Rate = }k{\left[\text{NO}\right]}^{\text{2}}\left[{\text{O}}_{\text{2}}\right]$

Which of the changes listed below would affect the value of the rate constant k?

a. increasing the partial pressure of oxygen gas

b. changing the temperature

c. using an appropriate catalyst