Question

question 13 of 27
at what temperatures is a reaction that has a positive change in entropy spontaneous?
a. at all temperatures for endothermic reactions
b. at all temperatures for exothermic reactions
c. at no temperatures for exothermic reactions
d. at lower temperatures for endothermic reactions

Explanation:

The spontaneity of a reaction is determined by the Gibbs - free energy change ($\Delta G$), where $\Delta G=\Delta H - T\Delta S$. When $\Delta S>0$ (positive change in entropy), for an exothermic reaction ($\Delta H < 0$), $\Delta G=\Delta H - T\Delta S$ will always be negative at all temperatures since $\Delta H$ is negative and $T\Delta S$ is positive. So the reaction is spontaneous at all temperatures for exothermic reactions.

Answer:

B. At all temperatures for exothermic reactions