To calculate the enthalpy change of combustion for the reaction of 0.5 moles of methane, we need to know the balanced chemical equation for the combustion of methane and the standard enthalpy change of combustion for methane.The balanced chemical equation for the combustion of methane is:CH g + 2O g CO g + 2HO l The standard enthalpy change of combustion for methane, Hc, is -890.3 kJ/mol.Now, we can calculate the enthalpy change for the combustion of 0.5 moles of methane:H = moles of methane Hc for methane H = 0.5 mol -890.3 kJ/mol H = -445.15 kJThe enthalpy change of combustion for the reaction of 0.5 moles of methane at standard conditions is -445.15 kJ.