A rate law expresses the rate of a reaction as a function of the concentration of reactants. For a reaction: \[ A + B \rightarrow C \] the rate law could be written as: \[ \text{Rate} = k[A]^m[B]^n \] where \( k \) is the rate constant, and \( m \) and \( n \) are the reaction orders with respect to reactants A and B, respectively.