If the vapor pressure of water in an open system at 25°C is 23.8 mmHg, what is ΔG for the reaction below at 25°C? H₂O(l) → H₂O(g, 23.8 mmHg) A) 0 kJ/mol B) -8.58 kJ/mol C) +8.58 kJ/mol D) -0.720 kJ/mol

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Quizplus · Accepted Answer

At equilibrium, the Gibbs free energy change (ΔG) for a process is zero. Since the vapor pressure of water is given as 23.8 mmHg, which is the equilibrium vapor pressure at 25°C, ΔG for the phase transition is 0 kJ/mol.

If the Vapor Pressure of Water in an Open System