Question

What happens when ΔH and ΔS have opposite signs?"

A) Reaction is always spontaneous.
B) Reaction is non-spontaneous.
C) Depends on temperature.
D) Equilibrium is reached.

Answer 1

When AH is negative and AS is positive, the reaction is spontaneous. When AH is positive and AS is negative, the reaction is non-spontaneous.

Step-by-step explanation:

When AH is negative and AS is positive, the sign of AG will always be negative, and the reaction will be spontaneous at all temperatures. This corresponds to both driving forces being in favor of product formation. When AH is positive and AS is negative, the sign of AG will always be positive, and the reaction can never be spontaneous. This corresponds to both driving forces working against product formation.