8. Calculate the standard enthalpy of formation, fHo (298K) of propane gas from its elements, given that at 298K and 1 bar pressure: the enthalpy of combustion of gaseous propane (cHo) = -2220 kJ mol-1; the enthalpy of formation of liquid water (fHo) = -286 kJ mol-1; the enthalpy of formation of gaseous carbon dioxide (fHo) = -393.5 kJ mol-1. Calculate also the total change in internal energy expected if the propane gas were formed in a bomb calorimeter.