When formulation the rate law for the reaction 2A + 3B + C -> 2D +E,

Question

in general we cannot use the stoichiometry of the reaction to formulate the rate law and the reaction order. Explain why the reaction order for the above reaction is not simply 2+3+1=6.

Answer 1

As stated in the question, we do not use stoichiometry of a reaction to formulate the rate law and the reaction order. So, it makes no sense to add the coefficients of the balanced equation to arrive at order = 6. The order must be determined experimentally. The only time you could use the stoichiometry would be if the reaction was an elementary step in a proposed mechanism.