<P> The exponents m and n are called partial orders of reaction and are not generally equal to the stoichiometric coefficients a and b . Instead they depend on the reaction mechanism and can be determined experimentally . </P> <P> The Arrhenius equation gives the quantitative basis of the relationship between the activation energy and the reaction rate at which a reaction proceeds . The rate constant is then given by </P> <Dl> <Dd> k = A e − E a R T (\ displaystyle k = Ae ^ (\ frac (- E_ (a)) (RT))) </Dd> </Dl> <Dd> k = A e − E a R T (\ displaystyle k = Ae ^ (\ frac (- E_ (a)) (RT))) </Dd>

Si units of a second order rate constant