Ethanol (C2H5OH) and gasoline (assumed to be all octane, C8H18) are both used as automobile fuel. If gasoline is selling for $4.50/gal, what would the price of ethanol have to be in order to provide the same amount of heat per dollar? The density and (H ° f of octane are 0.7025 g/mL and - 249.9 kJ/mol and of ethanol are 0.7894 g/mL and - 2277.0 kJ/mol, respectively. 1 gal = 3.785 L.