Gibbs Free Energy

ΔG° = ΔH° − T·ΔS°

= -92.4 − 298 × (-198.2/1000)

= -33.34 kJ/mol

Spontaneity

✓ Spontaneous (low T)

Spontaneous only at LOW T

Crossover at T = 466 K (193°C)

Spontaneity Guide:

ΔH− ΔS+ → Always spontaneous

ΔH+ ΔS− → Never spontaneous

ΔH− ΔS− → Spontaneous at LOW T

ΔH+ ΔS+ → Spontaneous at HIGH T

Equilibrium Constant

ΔG° = −RT ln Kc

Kc = e^(−ΔG°/RT) = 6.98e+5

Kc > 1: products favoured

ΔG° = ΔH° − T·ΔS°

ΔG° = −RT ln Kc    ΔG° = −nFE°

At equil: ΔG = 0, Q = Kc

ΔG° vs Temperature

Slope = −ΔS° = 0.1982 kJ/K  |  y-intercept = ΔH° = -92.4 kJ/mol | Crossover at 466 K

Current T = 298 K → ΔG° = -33.3 kJ/mol