Heats of formation for: ethanol: -277.6 kJ/mol octane: -208.5 kJ/mol H20 vapor: -241.8 kJ/mol CO2: -393/5 kJ/mol the density of ethanol is .789 g/mL the density of octane is .703 g/mL the efficiency of burning both is identical will anyone actually save money using ethanol (cost around $0.83 per liter) compared to gas at $1.10 per liter?