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Chemistry

Activation energy from two rate constants calculator

Activation energy from rate constants at two temperatures (two-point Arrhenius equation).

What this calculator does

Activation energy from two rate constants works out activation energy from rate constants at two temperatures (two-point Arrhenius equation). 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

FormulaEa = R·ln(k₂/k₁) / (1/T₁ − 1/T₂), R = 8.314462618 J/(mol·K) (CODATA)

The inputs explained

FieldWhat to enter
Rate constant k₁A number. Starts at 0.0021.
Temperature T₁ (K)A number, measured in K. Starts at 298.
Rate constant k₂A number. Starts at 0.031.
Temperature T₂ (K)A number, measured in K. Starts at 328.

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 rate constant k₁

Every other input is held at the calculator’s starting values while rate constant k₁ varies. Select any row to load that scenario into the calculator.

How the answer changes with rate constant k₁
Rate constant k₁Activation energy EaActivation energy Ealn(k₂/k₁)
0∞ kJ/mol∞ J/mol
0∞ kJ/mol∞ J/mol
0∞ kJ/mol∞ J/mol
0∞ kJ/mol∞ J/mol
0∞ kJ/mol∞ J/mol
0.0130.6 kJ/mol30,649 J/mol1.131