air/fuel ratio question (urgent again) Ok, I have an exam on monday and both my lecturers and tutor have gone walkabouts. So you guys are my last resort. Thanks. :) I get given a combustion chemical equation. Looks like this : aC6H18 + bO2 + 3.76bN2 --> 9.5CO + 9.5CO2 + 9.5H2O + 71.5N2 I solve for the coefficients. I can find the gravimetric a/f ratio, but I have no idea what to do to find the volumetric a/f ratio. Also, for the equivalence ratio, I have the actual ratio, so to find the stoich. ratio, do I just have to rewrite the equation so it looks like --> xCO2 + yH2O +zN2?? Thanks again guys.