What this calculator does
Arrhenius equation works out reaction rate constant at a given temperature from activation energy and pre-exponential factor. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
The inputs explained
| Field | What to enter |
|---|---|
| Pre-exponential factor A (/s) | A number, measured in /s. Starts at 10000000000000. |
| Activation energy Ea (J/mol) | A number, measured in J/mol. Starts at 75000. |
| Temperature (K) | A number, measured in K. Starts at 298.15. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with pre-exponential factor a
Every other input is held at the calculator’s starting values while pre-exponential factor a varies. Select any row to load that scenario into the calculator.
| Pre-exponential factor A (/s) | Rate constant k | Ea / (R·T) | Fraction with sufficient energy e^(−Ea/RT) |
|---|---|---|---|
| 5,000,000,000,000 | 0.36269242 /s | 30.255 | 7.2538e-14 |
| 7,500,000,000,000 | 0.54403863 /s | 30.255 | 7.2538e-14 |
| 10,000,000,000,000 | 0.72538484 /s | 30.255 | 7.2538e-14 |
| 15,000,000,000,000 | 1.08807726 /s | 30.255 | 7.2538e-14 |
| 20,000,000,000,000 | 1.45076968 /s | 30.255 | 7.2538e-14 |
| 30,000,000,000,000 | 2.17615452 /s | 30.255 | 7.2538e-14 |