Rate law equation The rate of a chemical reaction depends on the concentrations of the reactants. For the general reaction between AA and BB, aA+bB⇌cC+dD aA+bB⇌cC+dD The dependence of the reaction rate on the concentration of each reactant is given by the equation called the rate law: rate=k[A]m[B]rate=k[A]m[B]n where kkk is a proportionality constant called the rate constant. The exponent mmm determines the reaction order with respect to AA, and nnn determines the reaction order with respect to BB. The overall reaction order equals the sum of the exponents (m+nm+n).