Why higher temperature increases rate
Raising the temperature increases the kinetic energy of the particles. This increases reaction rate in two connected ways.
- Particle motion becomes faster. Collisions occur more frequently, giving more opportunities for successful collisions during a given time.
- A larger proportion has sufficient energy. More particles have energy equal to or greater than the activation energy, , so a greater proportion of collisions can result in reaction.
Together, these changes increase the frequency of successful collisions and therefore increase the reaction rate.
The activation-energy effect
The increase in the proportion of particles with has a greater effect on reaction rate than the increase in collision frequency alone. This accounts for the large rate increase that can result from a relatively small rise in temperature.
Exam Tip: For a complete temperature explanation, state both effects: collisions occur more frequently and a greater proportion of particles has energy equal to or greater than . Therefore successful collisions occur more frequently.