(A Level) Entropy and Gibbs free energy

Learning objectives

Explain entropy as a measure of the number of ways the particles in a system and their energy can be arranged, and predict the sign of ΔS for changes of state, dissolving, temperature change and changes in the number of gas molecules

Calculate ΔS⦵ for a reaction from standard entropies using ΔS⦵ = ΣS⦵(products) − ΣS⦵(reactants)

Calculate ΔG⦵ using ΔG⦵ = ΔH⦵ − TΔS⦵, converting ΔS to kJ K⁻¹ mol⁻¹, and use its sign to decide whether a reaction is feasible

Predict how temperature affects feasibility for each combination of signs of ΔH and ΔS, and calculate the temperature at which ΔG = 0