Water is formed when hydrogen burns in oxygen.

2H₂(g) + O₂(g) → 2H₂O(l) ΔH^θ_r = –561.6 kJ^–1 mol^–1

a. Calculate the entropy change of the system for this reaction.

(Values for S^θin J K^–1 mol^–1: H₂(g) = +130.6, O₂(g) = +205.0, H₂O(g) = +69.9)

b. Use your answer to part a and the information at the start of the question to calculate a value for the Gibbs free energy change of this reaction.

c. Is the reaction spontaneous at room temperature? Explain your answer.

d. Use your answer to part b to suggest a value for the standard Gibbs free energy of formation of H₂O(l). Explain your answer.