The balanced chemical reaction is 2Hg + O2 -> 2HgO. To calculate the delta G, we use the formula: ΔG = ΔH – TΔS. The ΔH is computed by subtracting the standard enthalpy of formation of the reactants from the products, multiplied correspondingly with their stoichiometric coefficients. The same is to obtain ΔS.
The necessary information all at 298 K are:
ΔH_Hg = 0 kJ/mol; since it is at its standard state
ΔS_Hg = 75.90 kJ/mol
ΔH_O2 = 0 kJ/mol; since it is at its standard state
ΔS_O2 = 0.161 kJ/mol K
ΔH_HgO = -90 kJ/mol
ΔS_HgO = 0.070 kJ/mol K
Thus, the delta G of reaction is -132.022 kJ. The negative value denotes a spontaneous reaction.
