Under which of the following conditions can an endothermic reaction be thermodynamically favorable?
(A) ΔG is positive (B) ΔS is negative (C) TΔS > ΔH (D) TΔS = 0
(E) There are no conditions under which an endothermic reaction can be thermodynamically favorable.
Answer and explanation:
To be thermodynamically favorable, a reaction must have negative ΔG (Gibbs Free Energy).
The formula for Gibbs Free Energy is ΔG = ΔH - TΔS where ΔS is entropy and ΔH is enthalpy. Since the question says that the reaction is endothermic, we know right away that ΔH is positive. Therefore, in order for ΔG to be negative, ΔS must be positive and temperature must be high enough to overcome the positive ΔH.
Choice C TΔS > ΔH is the correct choice.