To calculate the enthalpy change for the oxidation of 1 mole of methane gas to form carbon dioxide and water vapor, we can use the following equation:H_reaction = Hf products - Hf reactants For the given balanced chemical equation:CH4 g + 2O2 g CO2 g + 2H2O g The enthalpy of formation values are given as:Hf CH4 = -74.81 kJ/molHf CO2 = -393.51 kJ/molHf H2O = -241.83 kJ/molSince O2 is an element in its standard state, its enthalpy of formation is 0 kJ/mol.Now, we can plug these values into the equation: