Effect of temperature on reaction rates and the concept of activation energy

The Boltzmann distribution curve plots the number of molecules (y-axis) against kinetic energy (x-axis). The activation energy (Eₐ) is marked as a vertical line on the x-axis, representing the minimum energy required for reaction. The area to the right of Eₐ represents the number of molecules with sufficient energy to react.

Increasing the temperature flattens and broadens the Boltzmann distribution curve. This shifts the peak to the right (higher average kinetic energy) and increases the area under the curve to the right of the activation energy, indicating more molecules possess sufficient energy to react.

Increasing temperature increases the average kinetic energy of molecules. According to the Boltzmann distribution, a larger proportion of molecules now have energy exceeding the activation energy. This leads to a higher frequency of effective collisions, increasing the reaction rate.

A higher activation energy means that a smaller proportion of molecules will possess sufficient energy to overcome the energy barrier and react. Consequently, the reaction rate will be slower at a given temperature.

Due to the exponential nature of the Boltzmann distribution, even a small increase in temperature can significantly increase the *proportion* of molecules with energy exceeding the activation energy. This results in a disproportionately larger number of effective collisions and thus a significantly faster reaction rate.