To calculate the standard enthalpy change for the reaction, we need to know the standard enthalpies of formation for the reactants and products involved in the reaction. The balanced chemical equation for the reaction is:2 C s + O2 g 2 CO g The standard enthalpy of formation Hf for elemental carbon C in its standard state graphite is 0 kJ/mol, and for elemental oxygen O2 in its standard state gas is also 0 kJ/mol. The standard enthalpy of formation for carbon monoxide CO is -110.5 kJ/mol.Using Hess's Law, we can calculate the standard enthalpy change H for the reaction:H = [ Hf of products - Hf of reactants ]H = [2 -110.5 kJ/mol - 2 0 kJ/mol + 1 0 kJ/mol ]H = -221 kJSo, the standard enthalpy change for the reaction of 2 moles of carbon with 1 mole of oxygen to form carbon monoxide at standard conditions is -221 kJ.