Arrhenius Equation Calculator
Arrhenius equation calculator
Compute temperature-dependent rate constant from Arrhenius parameters.
InputsChemistry3 fieldsLive
Result
k = 8.7046e-3 s^-1
Uses k = A × exp(-Ea / (R × T)).
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Advanced options
Flow
- Enter pre-exponential factor A.
- Enter activation energy in kJ/mol and temperature in Kelvin.
- Read computed rate constant and apply to kinetic rate-law models.
Example
Worked example: A=1.2e11 1/s, Ea=75 kJ/mol, T=298.15 K
- 1 Convert Ea to J/mol: 75,000
- 2 Exponent = -Ea/(RT) = -75000/(8.314462618×298.15)
- 3 k = A×exp(exponent) ≈ 8.73e-3 1/s
Estimated rate constant is about 8.73 × 10^-3 1/s.
How
- Enter pre-exponential factor A.
- Enter activation energy in kJ/mol and temperature in Kelvin.
- Read computed rate constant and apply to kinetic rate-law models.
Avoid
- Using Celsius instead of Kelvin.
- Forgetting to convert activation energy from kJ/mol to J/mol in manual checks.
- Mixing incompatible units for pre-exponential factor and reaction order.
Ref only. Verify values. Follow lab safety.
FAQ
Why is Kelvin required?
Arrhenius thermodynamic form uses absolute temperature in Kelvin.
Can activation energy be zero?
Yes. That implies no exponential barrier term and k ≈ A.
Is this model valid for all mechanisms?
It is a common approximation and may deviate for complex multi-step systems.
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