Octane (C8H18) undergoes combustion according to the following thermochemical equation:
2C8H18(l) + 25O2(g) ? 16CO2(g) + 18H2O(l) ?H°rxn = -11,020 kJ/mol. Given that ?H°f[CO2(g)] = -393.5 kJ/mol and, H°f[H2O(l)] = -285.8 kJ/mol, Calculate the standard enthalpy of formation of octane?