How to use the fraction of molecules above activation energy calculator
Find the fraction of molecules with enough energy to cross an activation barrier at a given temperature. Enter activation energy, temperature in the fields above; the fraction of molecules above barrier, percent of molecules are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “Boltzmann fraction above activation energy”, “how many molecules have enough energy”, “exp(-Ea over RT)”, “calculate fraction of molecules above activation energy”, “find fraction of molecules above barrier”.
Formula
Variables
- Ea — Activation energy (kJ/mol)
- T — Temperature (K)
Worked example
With activation energy = 50 kJ/mol, temperature = 300 K, the calculator gives fraction of molecules above barrier ≈ 1.9697 × 10⁻⁹ fraction; percent of molecules ≈ 1.9697 × 10⁻⁷ %.
Frequently asked questions
What is the fraction of molecules above activation energy calculator used for?
Find the fraction of molecules with enough energy to cross an activation barrier at a given temperature. It helps with questions such as “Boltzmann fraction above activation energy”, “how many molecules have enough energy”, “exp(-Ea over RT)”.
What is the formula for the fraction of molecules above activation energy calculation?
Fraction of molecules above barrier (fraction) = exp(-Ea × 1000 / (RGAS × T)). Percent of molecules (%) = [Fraction of molecules above barrier] × 100. Here Ea is activation energy (kJ/mol), T is temperature (K).
What inputs do I need for the fraction of molecules above activation energy calculator?
You need activation energy in kJ/mol, temperature in K. 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 fraction of molecules above activation energy 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 fraction of molecules above activation energy 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.