Rate Constant Calculator

Rate Constant Calculator

Calculate reaction rate constants easily

Result

Rate Constant Calculator

This calculator helps you determine the rate constant (k) for chemical reactions of different orders (zero, first, or second order). The rate constant is a proportionality constant in the rate law that relates the reaction rate to the concentrations of reactants.

How to Use This Calculator

  1. Select the reaction order from the dropdown menu
  2. Enter the initial concentration of the reactant (in molarity, M)
  3. Enter the final concentration of the reactant (in molarity, M)
  4. Enter the time period over which the concentration change occurred (in seconds)
  5. Click "Calculate Rate Constant" to get your result

Formulas Used

Zero Order Reaction: [A]₀ - [A] = kt

First Order Reaction: ln([A]₀/[A]) = kt

Second Order Reaction: 1/[A] - 1/[A]₀ = kt

Where:

  • [A]₀ = initial concentration
  • [A] = final concentration
  • k = rate constant
  • t = time

Example Calculation

First Order Reaction:

Initial concentration: 1.0 M

Final concentration: 0.5 M

Time: 30 seconds

Using the first order formula: ln(1.0/0.5) = k × 30

ln(2) = 30k → k ≈ 0.693/30 ≈ 0.0231 s⁻¹

The rate constant is a fundamental parameter in chemical kinetics that helps predict how fast a reaction will proceed under given conditions.