The enthalpy of formation of a compound is the change in enthalpy when one mole of the compound is formed from its constituent elements in their standard states. The balanced chemical equation for the formation of CO2 is:C graphite + O2 g CO2 g The enthalpy of formation for carbon C in its standard state graphite is 0 kJ/mol, not -94 kJ/mol as mentioned in the question. The enthalpy of formation for oxygen O2 in its standard state gas is also 0 kJ/mol.To find the enthalpy of formation for CO2, we can use the following equation:Hf CO2 = [Hf products ] - [Hf reactants ]In this case, the reactants are C graphite and O2 g , and the product is CO2 g . Since the enthalpy of formation for both reactants is 0 kJ/mol, the equation simplifies to:Hf CO2 = Hf CO2 - 0Therefore, the enthalpy of formation of CO2 is equal to the enthalpy of formation of CO2 itself. The standard enthalpy of formation for CO2 g is -393.5 kJ/mol.