23.4.3—Feasibility from ΔG sign
- Syllabus
- 9701–2028–2029
- Objective
- 23.4.3
- Level
- A2
A negative ΔG° indicates a thermodynamically feasible forward process under stated conditions
If ΔG° < 0, the forward process is thermodynamically feasible under the specified standard conditions; if ΔG° > 0, the reverse direction is favoured. ΔG° = 0 indicates equilibrium.
Feasible does not mean fast, safe or complete. Kinetics, activation energy, heat transfer and actual concentrations can determine what is observed.
A combustion reaction may have a strongly negative ΔG° but still need ignition because its activation energy is high.
Do not equate negative ΔG° with an instantaneous reaction or 100% yield.
ConceptA-Level CAIE Chemistry A2