Consider the rate law rate = k[Y] m [Z] n are the m and n coefficients in the balanced chemcial reaction ?

The power of the concentration of the reactant in the rate law equation is the order of the each reactant which we find experimentally, the stoichiometric coefficient in the balanced equation for a chemical reaction is different from the order of the reaction .

So, m and n are experimentally determined and they are not the coefficients of the balanced reaction .