Question

Is this spontaneous or nonspontaneous at high temperatures?

H°: negative
S°: positive
Low temperature: spontaneous a) Spontaneous
b) Nonspontaneous
c) Depends on external factors
d) Cannot be determined from the given information

Answer 1

With negative enthalpy change and positive entropy change, at high temperatures the process is always spontaneous, as this will result in the Gibbs free energy becoming more negative.

Step-by-step explanation:

The question indicates that a process has negative ΔH° (enthalpy change) and positive ΔS° (entropy change). From thermodynamic principles, we know that the spontaneity of a reaction can be determined by the Gibbs free energy equation ΔG = ΔH - TΔS, where ΔG < 0 indicates a spontaneous process. If ΔH is negative and ΔS is positive, the reaction is always spontaneous, as the TΔS term will always be positive and will increase with temperature, thus making the ΔG more negative. Therefore, at high temperatures, given that ΔH° is negative and ΔS° is positive, the process is spontaneous.