Chapter 15 Question 65

[William_Lee_Dis_3H]

Why would increasing the temperature increase the rate constant of the reaction with the higher activation barrier more than it will the rate constant of the reaction with the lower energy barrier?

[Alex Chen 1B]

The rate of a reaction with a lower activation energy barrier isn't as affected by increasing temperature because once the reaction reaches a temperature that allows it to get over its energy barrier, the rate basically stays the same. The rate of a reaction with a higher activation energy barrier, on the other hand, is affected by increasing temperature. This occurs because as you increase the temperature, you're increasing the rate of the reaction by supplying the system with more energy to overcome the barrier, which would increase the reaction rate. At higher temperatures, the reaction with the lower activation energy barrier has likely already fulfilled its energy requirement so its rate is not as dependent on temperature. The reaction with the higher activation energy would increase in rate if the temperature was increased.