During the combustion of 5.0g of octane C8H18, 239.5 kcal is released. a)write a balanced equation for the combustion reaction. b)what is the sign of H for this reaction. c) how much energy is released by the combustion of 1.0mol of C8H18? d)How many grams and how many moles of octane must be burned to release 450 kcal? e)How many kilocalories are released by the combustion of 17g of C8H18?