Exothermic reactions with negative values of S ° are spontaneous at all temperatures.

Question

Quizplus · Accepted Answer

Exothermic reactions with negative values of $ \Delta S^\circ $ (change in entropy) are not necessarily spontaneous at all temperatures. The spontaneity of a reaction depends on the Gibbs free energy change ($ \Delta G^\circ $), which is influenced by both $ \Delta H^\circ $ (enthalpy change) and $ \Delta S^\circ $ (entropy change), as well as the temperature of the system. For a reaction with $ \Delta H^\circ < 0 $ (exothermic) and $ \Delta S^\circ < 0 $ (decrease in entropy), $ \Delta G^\circ $ becomes less negative or even positive as the temperature increases, making the reaction non-spontaneous at high temperatures.

Exothermic Reactions with Negative Values of S ° Are Spontaneous