Many gases dissolve exothermically in water and exhibit a decrease in molar entropy during dissolution. Consider a gas G that dissolves according to the process G(g)→G(aq) with ΔHdiss∘=−20.0kJmol−1 and ΔSdiss∘=−70.0Jmol−1K−1 (assumed constant).
(a) Derive an algebraic expression for the maximum temperature at which the dissolution of gas G is spontaneous under standard-state conditions, leaving your result in terms of ΔHdiss∘ and ΔSdiss∘.
(b) Using the values provided, calculate that maximum temperature in kelvins.
(c) Explain, with reference to both enthalpy and entropy, why the solubility of gas G (and gases with similar thermodynamic signatures) generally decreases as the temperature of the water increases beyond the temperature found in part (b).