First of all, how do you know if a combustion process produce h2o(g) or h2o(l)??? It depends on the temperature, but how do you figure that out? I found the heat released during the combustion processes, which should equate the work done by the system (theoretically). But according to w = -nRT[ln(V2/V1)], I need the initial volume and final volume. The pressure remains constant (I believe), and V can be figured by PV=nRT with P=1 atm throughout. And with that, I need the temperature. to figure out the temperature, I need the specific heat. But what specific heat do I need? those of the reactants or the products??? my brain iis hurrrts badd btw, here are the reactants: C8H18 (Octane), C2H5OH (ethanol), methane ch4, h2, and nh4.