Mark, I know you wrote this a while ago, but I've been meaning to comment on it. I would be very surprised if (in general when reacting chemicals together), one needs to place greater quantities of one chemical in order to ensure sufficient reaction completion (assuming reaction rate time constants are not in the order of hours or days). I'm going to assume that the percent of reactant and product both change exponentially w.r.t. time. If so then the reaction will have a time constant (k), such that for a first order reaction,
Originally Posted by albada
[A(t)] = [A(0)] exp(kt)
unless k is in the order of hours or days (lets say it is in the order of seconds) then surely you will have sufficient equilibrium after a matter of minutes ? OK I just read here (Summary for reaction orders 0, 1, 2, and n) , that perhaps you have a zero order reaction. Is that the case ? In which case the product concentration only rises linearly not exponentially. Even then I don't imagine you would gain much time advantage by upping a reactant.
Disclaimer: I'm a mathematician and electrical engineer, not a chemist !