Calculate the standard (25°C and 1 atmosphere) heat of reaction in gram mole of the first reactant on the left-hand side of the reaction equation of the following reactions a. CH4 (g) + 2 O2 (g) ? CO2 (g) + 2 H2O (l) b. CO2 (g)+ H2 (g) ? CO (g) + H2O (l)