A molecular solid dissolves endothermically with a positive standard entropy change
CHEMISTRY · Single correct · A Level · Chemistry · Thermodynamics · Thermodynamics
Problem
A molecular solid dissolves endothermically with a positive standard entropy change. Which of the following best predicts how its solubility will change when the solution temperature is increased?
(a) Solubility decreases because the dissolution process becomes less spontaneous at higher T (the TΔS term is thought to raise ΔG).
(b) Solubility increases because the dissolution process becomes more spontaneous at higher T.
(c) Solubility decreases because an endothermic process is driven toward the solid phase when heat is supplied, according to Le Châtelier’s principle.
(d) Solubility is unaffected because the positive enthalpy and entropy effects exactly cancel over the temperature range.