Ammonia is synthesized industrially according to the balanced equation
N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g).
At 298 K, the standard enthalpy change is ΔH° = –92.4 kJ mol⁻¹ and the standard entropy change is ΔS° = –198 J mol⁻¹ K⁻¹.
The gas constant is R = 8.314 J mol⁻¹ K⁻¹.
(a) Calculate the standard Gibbs free-energy change ΔG° for the formation of ammonia at 298 K. Include the correct sign and units.
(b) Determine the numerical value of the equilibrium constant K at 298 K. Report K to an appropriate number of significant figures.
(c) Interpret the magnitude of K with respect to the extent of ammonia formation under standard conditions.