Given that S(g) + O2(g) ? SO2(g) ?G° = -300.1 kJ 2S(g) + 3O2(g) ? 2SO3(g) ?G° = -742.1 kJ calculate ?G° of the following reaction: SO2(g) + 1/2 O2(g) ? SO3(g) -1042.2 kJ -71.0 kJ +2.47 kJ +71.0 kJ +1042.2 kJ