Given that the standard free energy of formation of MCl2(s) and MO2(s) are, respectively, -311.5 and -286.5 kJ/mol at 25o C. What is the standard change in free energy (kJ) for the following reaction? [Note (all at 25oC): Standard free energies of formation for H2(g), O2(g), and HCl(g) are, respectively, 0, 0, and and -95.30 kJ/mol.]
MCl2(s) + O2(g) + H2(g) ? MO2(s) + 2 HCl(g)