For a reaction to be spontaneous under standard conditions at all temperatures, the signs of ΔH° and ΔS° must be _ _ and , respectively.

Question

Quizplus · Accepted Answer

A reaction is spontaneous when ΔG is negative. The formula for ΔG under standard conditions is ΔG° = ΔH° - TΔS°, where T is the temperature in Kelvin. For the reaction to be spontaneous at all temperatures, ΔG° must be negative at all temperatures. This can only happen if ΔS° is positive (favorable entropy change) and if ΔH° is negative (favorable enthalpy change). Therefore, the correct answer is C) - , + where a negative ΔH° and positive ΔS° would make ΔG° negative at all temperatures.

For a Reaction to Be Spontaneous Under Standard Conditions at All