Calculate the change in Gibbs free energy for a reaction at equilibrium using the equation ΔG = ΔH - TΔS, given ΔH = 0 kJ/mol, T = 298 K, and ΔS = 0 J/mol·K.

• A. ΔG = 298 kJ/mol, indicating the reaction is non-spontaneous.
• B. ΔG = -298 kJ/mol, indicating the reaction is spontaneous.
• C. ΔG = 0 J/mol, indicating the reaction is at equilibrium.
• D. ΔG = 0 kJ/mol, indicating the reaction is at equilibrium.

Answer: (D)