If the activation energy of a reaction is 100 kJ mol⁻¹, the presence of a catalyst lowers it by 75 kJ mol⁻¹. The rate of the reaction at 27 °C will increase by a factor of (R = 8.314 J K⁻¹ mol⁻¹):
For a reaction, the rate constant at 500 K is twice the rate constant at 400 K. The activation energy (in kJ mol⁻¹) is approximately (R = 8.314 J K⁻¹ mol⁻¹):
The rate constant of a reaction at 500 K is 1.6 × 10³ times the rate constant at 400 K. The activation energy of the reaction is (log 1600 ≈ 3.204, R = 8.314 J K⁻¹ mol⁻¹):
