Acids, equilibrium & kinetics · HL
Arrhenius Activation Energy Calculator (HL)
HL tool. Enter temperatures in kelvin and positive rate constants in the same units.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
ln(k₂/k₁) = −Eₐ/R (1/T₂ − 1/T₁)
k = Ae^(−Eₐ/RT)
| Symbol | Meaning |
|---|---|
| Eₐ | Activation energy. |
| A | Pre-exponential factor in the same units as k. |
When to use this calculator
This two-point form assumes an Arrhenius model over the temperature interval. A multi-point plot of ln k against 1/T is usually stronger evidence.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- ln(k₂/k₁) = ln(0.03/0.01) = 1.098612
- 1/T₁ − 1/T₂ = 0.000210845
- Eₐ = R ln(k₂/k₁)/(1/T₁ − 1/T₂) = 43322.69 J mol⁻¹ = 43.32269 kJ mol⁻¹
- A = k₁e^(Eₐ/RT₁) = 388871.7
43.32269 kJ mol⁻¹
Common mistakes
- Temperature must be in K.
- The units of A follow the units of k.