📉 Arrhenius Equation Calculator
Use the two-point Arrhenius equation to get the activation energy from two rate constants and temperatures — or find k at a new temperature.
Activation energy Ea
178036 J/mol
Two-point Arrhenius: ln(k₂/k₁) = −(Ea/R)·(1/T₂ − 1/T₁), R = 8.314 J/(mol·K). Temperatures in kelvin. 🔒 Computed in your browser.
How the arrhenius equation calculator works
The two-point form is ln(k₂/k₁) = −(Ea/R)·(1/T₂ − 1/T₁), with R = 8.314 J/(mol·K) and temperatures in kelvin. Enter two rate constants and their temperatures to get the activation energy Ea; or give Ea and one (k, T) pair to predict the rate constant at another temperature.
The standard way to extract activation energy from kinetics data without plotting. Rate constants roughly double for every 10 K near room temperature when Ea is around 50 kJ/mol.
Frequently asked questions
What is the Arrhenius equation?
k = A·e^(−Ea/RT), relating a rate constant to temperature. The two-point form, ln(k₂/k₁) = −(Ea/R)(1/T₂ − 1/T₁), lets you find the activation energy from two measurements.
How do I find activation energy from two temperatures?
Enter the two rate constants and their kelvin temperatures; the tool computes Ea = −R·ln(k₂/k₁) / (1/T₂ − 1/T₁).
What is activation energy?
The minimum energy barrier a reaction must overcome. A higher Ea means the rate is more temperature-sensitive.
Can I predict a rate constant at a new temperature?
Yes — give the activation energy and a known (k, T) pair, then solve for k₂ at the target temperature T₂.
What units is activation energy in?
This tool reports Ea in J/mol (divide by 1000 for kJ/mol), using R = 8.314 J/(mol·K).