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Arrhenius Reaction Rate & Activation Energy Calculator engineering
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Arrhenius Reaction Rate & Activation Energy Calculator

Calculate temperature-dependent reaction rate constants (k), solve for activation energy (Ea) from experimental data, and determine kinetic temperature sensitivity.

Calculation Mode

Arrhenius Kinetics Results

Predicted Rate Constant (k)
--
at -- °C (-- K)
Activation Energy
-- kJ/mol
-- kcal/mol
Rate Doubling Temp
+-- °C
ΔT to 2× reaction speed
Pre-Exponential Factor (A): --
10°C Acceleration Factor (Q10): --×
Boltzmann Fraction exp(-Ea/RT): --
The Arrhenius equation describes the exponential increase of chemical reaction rates with temperature due to molecules overcoming the activation energy barrier.

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Frequently Asked Questions

What is the physical meaning of activation energy (Ea)?

Activation energy is the minimum kinetic energy reactant molecules must possess upon colliding to break existing chemical bonds and form transition states. Reactions with higher Ea values (e.g. >100 kJ/mol) proceed slowly at room temperature and exhibit extreme sensitivity to temperature spikes.

What is the "rule of thumb" that reaction rates double for every 10°C increase?

This classic rule of thumb applies specifically to reactions with an activation energy of approximately 50 to 55 kJ/mol near room temperature (300 K). If Ea is higher (e.g. 100 kJ/mol), a 10°C rise can quadruple or quintuple the rate, which is why exothermic reactions can run away so rapidly.

What does the pre-exponential frequency factor (A) represent?

The pre-exponential factor A represents the total frequency of molecular collisions that have the correct steric orientation to react. For unimolecular gas-phase reactions, A is typically near 10^13 s⁻¹ (the fundamental molecular vibration frequency).