How to Calculate Rate Constant (k)
Compute Arrhenius rate constant step-by-step:
Enter Frequency Factor A
Input pre-exponential collision frequency factor A in scientific notation (e.g. 1.0e11).
Enter Activation Energy Ea
Input activation energy Ea in kJ/mol.
Enter Temperature T
Input absolute reaction temperature T in Kelvin (K).
Compute k & Half-Life
Calculate rate constant k and 1st order half-life t1/2 = 0.693 / k.
Key Features & Collision Theory
Arrhenius Exponential Engine
Uses exact exponential expression k = A · e^(-Ea / RT).
Boltzmann Factor Display
Shows fraction of molecular collisions exceeding the activation energy barrier.
Half-Life Estimator
Computes 1st order kinetic half-life t½ = ln(2) / k.
Kinetics Guide: The Arrhenius Rate Constant
The rate constant (k) measures reaction velocity independent of concentration:k = A · e^(-Ea / (R · T))As temperature T increases, the exponential term e^(-Ea/RT) approaches 1.0, increasing k rapidly.
Frequently Asked Questions
?What are the units of rate constant k?
For a 1st order reaction, k is in s⁻¹. For a 2nd order reaction, k is in M⁻¹s⁻¹ (L/(mol·s)).