Octane (c8h18) undergoes combustion according to the following thermochemical equation: 2c8h18(l) + 25o2(g) → 16co2(g) + 18h2o(l), δh°rxn = –11,020 kj/mol. Given that δh°f[co2(g)] = –393. 5 kj/mol and δh°f[h2o(l)] = –285. 8 kj/mol, calculate the standard enthalpy of formation of octane.