Chapter 16 - Thermodynamics: Directionality of Chemical Reactions - Questions for Review and Thought - More Challenging Questions - Page 737h: 119a

$142.12\,kJ/mol$

$\Delta_{r}G^{\circ}=\Sigma n_{p}\Delta_{f}G^{\circ}(products)-\Sigma n_{r}\Delta _{f}G^{\circ}(reactants)$ $=[\Delta_{f}G^{\circ}(CO,g)+3\Delta_{f}G^{\circ}(H_{2},g)]-[\Delta_{f}G^{\circ}(CH_{4},g)+\Delta_{f}G^{\circ}(H_{2}O,g)]$ $=[(-137.168\,kJ/mol)+3(0)]-[(-50.72\,kJ/mol)+(-228.572\,kJ/mol)]$ $=142.12\,kJ/mol$