Rate Law
An experimentally determined equation expressing reaction rate as a function of reactant concentrations.
Formula / equation
rate = k[A]^m[B]^n
Unit
mol/(L·s)
In depth
The exponents are the orders with respect to each reactant and must be found by experiment — they bear no necessary relation to the stoichiometric coefficients. The rate law reflects only the steps up to and including the rate-determining step, making it the primary evidence for any mechanism.
Examples in the real world
The reaction of NO₂ with CO is rate = k[NO₂]², independent of CO concentration entirely.