I think that it is wrong to have the stoichiometric coefficients as the exponents. That should be reaction order which is determined experimentally and not correlated with stoichiometric coefficients for the k lower case.
but also, you can use coefficients as the exponents if the elementary step used is the rate-limiting reaction (when he set's up Rforward=Rreverse he is assuming this is a "single-step" reaction)
I think that it is wrong to have the stoichiometric coefficients as the exponents. That should be reaction order which is determined experimentally and not correlated with stoichiometric coefficients for the k lower case.
you would be right if he was solving for rate laws.
but also, you can use coefficients as the exponents if the elementary step used is the rate-limiting reaction (when he set's up Rforward=Rreverse he is assuming this is a "single-step" reaction)