IB Chemistry 1.4.3 (HL) Spontaneity Questions
IB Chemistry 1.4.3 (HL) Spontaneity Questions
Work through Gibbs free energy questions by deciding when reactions are spontaneous and calculating the temperature where the sign of ΔG changes.
How this is tested
- deduce the signs of ΔH and ΔS from whether a reaction is spontaneous at low T, high T, or both
- find the threshold temperature by setting ΔG = 0, e.g. using ΔH = -312 kJ mol−1 and ΔS = -233 J K−1 mol−1
- explain temperature effects on spontaneity through the changing size of the -TΔS term in ΔG = ΔH - TΔS