To calculate the heat of formation of methane CH4 at standard conditions using the bond energy method, we need to consider the bond energies of the reactants and products involved in the formation reaction.The formation reaction for methane is:C graphite + 2H2 g CH4 g We will use the average bond energies for the bonds involved in this reaction. The bond energies are as follows:C-H bond energy: 414 kJ/molH-H bond energy: 436 kJ/molC graphite : Since it is an allotrope of carbon, its energy is considered to be zero.Now, we will calculate the energy required to break the bonds in the reactants and the energy released when the bonds in the products are formed.Energy required to break bonds in reactants:2 moles of H2: 2 436 kJ/mol = 872 kJEnergy released when bonds in products are formed:4 moles of C-H bonds: 4 414 kJ/mol = 1656 kJNow, we can calculate the heat of formation Hf of methane:Hf = Energy required to break bonds - Energy released when bonds are formedHf = 872 kJ - 1656 kJHf = -784 kJ/molSo, the heat of formation of methane CH4 at standard conditions 25C and 1 atm pressure using the bond energy method is -784 kJ/mol.