Equilibrium & Le Chatelier
Dynamic equilibriumBoth reactions continue at equal rates.
N₂O₄ dimer NO₂ molecule molecules remain in motion
Equilibrium mixture
NO₂ in mixture31%
N₂O₄ in mixture69%
Degree of dissociation0.19
Total gas amount1.19 mol
Cooling favours N₂O₄. Lower pressure allows the side with more gas molecules to form.
Quantitative ideal-gas model: the vessel starts with 1.00 mol N₂O₄, Kp is anchored at 25 °C and adjusted with the van ’t Hoff equation using ΔH° = +57.2 kJ mol⁻¹. The selected pressure is the equilibrium total pressure.
- Heat the bath until the mixture contains more than 70% NO₂
- Cool and compress the gas until it contains less than 10% NO₂
- Create a mixture containing almost exactly 50% NO₂
- Above 60°C, compress the gas enough to bring NO₂ below 50%