CHM2046 - Chemistry Fundamentals II: Free Energy and Thermodynamics

These flashcards cover key concepts in thermodynamics and free energy related to chemical reactions, including spontaneity and entropy.

What is the Heat Death of the universe?

A state of no thermodynamic free energy.

What must Gibbs free energy change (ΔG) be for a reaction to be spontaneous?

ΔG must be negative.

In which case is a reaction never spontaneous?

When ΔH is positive and ΔS is negative.

What is the relationship between ΔH, ΔS, and temperature for spontaneous reactions?

ΔG = ΔH - TΔS; for spontaneity, ΔG < 0.

What occurs during the sublimation of dry ice?

ΔH is negative, ΔS is positive, and ΔG is negative at all temperatures.

What is the Third Law of Thermodynamics?

The entropy for a perfect crystal at 0 K is zero.

How does molar mass affect relative standard entropy?

The larger the molar mass, the larger the entropy.

What is the formula for calculating standard entropy change (ΔSo rxn) for a reaction?

ΔSo rxn = Σ(np So of products) - Σ(nr So of reactants).

What is the significance of standard molar entropy (So)?

It is the entropy of 1 mole of substance at 298 K under specific conditions.

Which phase generally has the highest standard molar entropy?

Gaseous phase has the highest standard molar entropy compared to solids and liquids.

What happens when you calculate ΔGo rxn and find a negative value?

The reaction is spontaneous.