Rate Constant Calculator
Determine the rate constant k from experimental rate and concentration data.
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Enter the rate and concentration of reactant A for two experiments where only [A] changes. The calculator determines the reaction order from the ratio of rates and concentrations, then calculates k.
About the Rate Constant Calculator
The rate constant k is a proportionality constant in the rate law that relates reaction rate to reactant concentrations. Its value depends on temperature but not on concentration. Determining k from experimental data is a fundamental task in chemical kinetics.
Frequently Asked Questions
How do I determine reaction order from data?
Compare two experiments where only one reactant concentration changes. The order n = ln(rate2/rate1) / ln([A]2/[A]1). If doubling concentration doubles the rate, n = 1. If it quadruples the rate, n = 2.
What are the units of the rate constant?
Units depend on the overall reaction order. For first order: 1/s. For second order: 1/(M s). For zero order: M/s. The units ensure the rate law gives rate in M/s.
Can the reaction order be a fraction?
Yes. While integer orders (0, 1, 2) are most common, fractional orders occur in complex reactions with multiple elementary steps. This calculator rounds to the nearest integer for simplicity.