Calculate r G for the decomposition of sulfur trioxide to sulfur dioxide and oxygen. 2 SO

Calculate Δ_rG° for the decomposition of sulfur trioxide to sulfur dioxide and oxygen.
2 SO₃(g) ⇄ 2 SO₂(g) + O₂(g)
(a) Is the reaction product-favored at equilibrium at 25°C?
(b) If the reaction is not product-favored at 25°C, is there a temperature at which it will become so? Estimate this temperature.
(c) Estimate the equilibrium constant for the reaction at 1500°C.