Using the exponential form of the Arrhenius equation,
rate constants measured at different temperatures can be used
- to determine Eaand A graphically and then
- to use A to calculate the rate constant at a different temperature
A form of the Arrhenius equation in which
A does not appear can be derived by taking the difference between the logarithmic form at two different temperatures.
| ln k2 | = | - | Ea | × | 1 | + ln A |
| R | T2 |
minus
| ln k1 | = | - | Ea | × | 1 | + ln A |
| R | T1 |
equals
| ln | k2 | = | - | Ea | ( | 1 | - | 1 | ) |
| k1 | R | T2 | T1 |
This relationship is a convenient way
- to calculate Ea from k at two different temperatures
- to determine k at a second temperature from k at one temperature and Ea