Arrhenius Rate Constant Calculator

Summary

Enter the pre-exponential factor A, activation energy Ea, and temperature T to compute the rate constant k from k = A·e^(−Ea/RT).

How it works

1. Enter the pre-exponential factor A (in s⁻¹ for first-order or L·mol⁻¹·s⁻¹ for second-order reactions).
2. Enter the activation energy Ea and choose units: J/mol or kJ/mol.
3. Enter the temperature and choose units: Kelvin (K) or Celsius (°C).
4. Click Calculate — the tool evaluates k = A·e^(−Ea/RT) and displays the result with scientific notation.
5. Review the step-by-step substitution and the ln(k) value for linearized Arrhenius analysis.
6. Optionally enter a second temperature to compare k values and see the k₂/k₁ ratio.

Use cases

• Predict how fast a reaction runs at a specific temperature using known kinetics parameters.
• Compare k at two temperatures to quantify the effect of heating on reaction speed.
• Verify rate constant calculations for physical chemistry homework or lab reports.
• Estimate shelf-life changes from temperature shifts using rate constant ratios.
• Teach or demonstrate exponential temperature dependence in kinetics courses.
• Cross-check k values extracted from Arrhenius plots (ln k vs. 1/T).
• Evaluate whether a reaction is feasible at a given temperature based on its k.
• Screen candidate catalysts by comparing pre-exponential factors and activation energies.

Frequently Asked Questions