Ethanol is added to gasoline because the oxygen it contains improves gasoline's burning efficiency. Its combustion reaction is given below. CH3CH2OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ∆H = - 1236 kJ a) Is this an exothermic or endothermic reaction? b) If 15.3 grams of pure ethanol is completely converted to products, calculate how much heat is absorbed or released, in: (1) kJ and in (2) kcal c) If 42.7 g of water vapor is produced, how much heat, in kJ, is absorbed or released?