Reaction Rate Constant Calculator – Calculate k from Rate and Concentration
Calculate the rate constant (k) for chemical reactions from rate and concentration data. This chemistry calculator supports zero, first, and second order reactions with half-life calculations.
Reaction Data
Rate Constant Results
Enter reaction data to calculate rate constant
Reaction Order Characteristics
Zero Order
- Rate = k
- Units: M/s
- t½ = [A]₀/2k
- Rate independent of [A]
First Order
- Rate = k[A]
- Units: s⁻¹
- t½ = ln(2)/k
- Half-life is constant
Second Order
- Rate = k[A]²
- Units: M⁻¹s⁻¹
- t½ = 1/(k[A]₀)
- Half-life depends on [A]₀
Frequently Asked Questions
What is the rate constant k?
The rate constant k is a proportionality factor in the rate law that relates reaction rate to reactant concentrations. It's specific to each reaction and temperature.
How do I determine reaction order?
Reaction order is determined experimentally by measuring how rate changes with concentration. Plot concentration vs time data or use the method of initial rates.
What affects the rate constant?
Temperature (Arrhenius equation), catalysts, and activation energy affect k. Concentration does NOT affect the rate constant itself, only the rate.
What is half-life?
Half-life is the time for reactant concentration to decrease by half. For first-order reactions, it's constant. For other orders, it depends on initial concentration.
What are the units of k?
Units depend on order: zero order (M/s), first order (s⁻¹), second order (M⁻¹s⁻¹). General formula: M^(1-n)/s where n is the order.