How to use the eyring equation rate constant calculator
Find the rate constant of a reaction from its free energy of activation using transition state theory. Enter temperature, free energy of activation in the fields above; the rate constant, half-life for first order reaction are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “Eyring equation”, “transition state rate constant”, “rate from activation free energy”, “calculate eyring equation rate constant”, “find rate constant”.
Formula
Variables
- T — Temperature (K)
- dG — Free energy of activation (kJ/mol)
Worked example
With temperature = 298.15 K, free energy of activation = 80 kJ/mol, the calculator gives rate constant ≈ 0.05996094 s⁻¹; half-life for first order reaction ≈ 11.55998 s.
Tips for accurate results
- Enter the temperature in kelvin; 25 °C is 298.15 K.
- Enter the free energy of activation in kJ/mol, as the calculator converts it to J/mol.
- The rate constant comes from transition state theory, so the result assumes that model applies to the reaction.
Common mistakes
- Entering temperature in degrees Celsius, which gives a wrong rate constant.
- Confusing the free energy of activation with the Arrhenius activation energy; they are related but not identical.
- Assuming the calculated rate applies to a reaction with a different mechanism.
Frequently asked questions
What is the eyring equation rate constant calculator used for?
Find the rate constant of a reaction from its free energy of activation using transition state theory. It helps with questions such as “Eyring equation”, “transition state rate constant”, “rate from activation free energy”.
What is the formula for the eyring equation rate constant calculation?
Rate constant (s⁻¹) = KB × T / HPLANCK × exp(-dG × 1000 / (RGAS × T)). Half-life for first order reaction (s) = ln(2) / [Rate constant]. Here T is temperature (K), dG is free energy of activation (kJ/mol).
What inputs do I need for the eyring equation rate constant calculator?
You need temperature in K, free energy of activation in kJ/mol. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the eyring equation rate constant calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the eyring equation rate constant result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.