The following thermodynamic data are available for octane, oxygen gas, carbon dioxide gas, water, and water vapor: molecule δh∘f (kj/mol) c8h18(l) −250.1 o2(g) 0 co2(g) −393.5 h2o(l) −285.8 h2o(g) −241.8 part b calculate δhrxn for the combustion of octane by using enthalpies of formation from the transition above. express the energy in kilojoules per mole to three significant figures. δhrxn δ h r x n = nothing kj/mol