A reaction is exothermic and has a negative value of DS^$\circ$. The value of DG^$\circ$ for this reaction is therefore:

Question

Quizplus · Accepted Answer

By definition, ΔG = ΔH - TΔS, where ΔH is the enthalpy change, T is the temperature in Kelvin, and ΔS is the entropy change. Since the reaction is exothermic (ΔH is negative) and ΔS is also negative, ΔG will be negative at low temperatures. However, as the temperature increases, the TΔS term becomes more significant, and eventually, ΔG will become positive. Therefore, the answer is D, where ΔG is positive above a certain temperature (which depends on the values of ΔH and ΔS) and negative below it.

A Reaction Is Exothermic and Has a Negative Value of DS