Le Chatelier's Chamber

Le Chatelier's Chamber is an interactive 3D gas-phase equilibrium simulation designed for chemistry classrooms. Inside a sealed glass cylinder with a draggable top piston and a heated base jacket, 36 colliding gas molecules continuously interconvert between reactants and products. Students can test the endothermic dinitrogen tetroxide dissociation (N2O4 ⇌ 2 NO2, where colourless cyan dimers split into reddish-brown monomers) or the exothermic Haber ammonia synthesis (N2 + 3 H2 ⇌ 2 NH3). Dragging the piston changes volume and pressure immediately, while adjusting temperature changes the equilibrium constant Kc, letting students watch forward and reverse rates rebalance until Q equals Kc.

• In the N2O4 ⇌ 2 NO2 system, raise the Temperature slider toward 450 K and watch the gas mixture darken as endothermic dissociation shifts right toward brown NO2.
• Drag the top piston downward to compress the chamber volume from 5.0 L to 1.8 L and watch N2O4 dimers reform as equilibrium shifts toward fewer moles of gas.
• Switch System to N2 + 3 H2 ⇌ 2 NH3 (Exothermic) and compress the piston to see why high pressure favours ammonia production in the Haber process.
• Lower the temperature in the Haber system and observe how an exothermic reaction shifts toward products (higher Kc) when cooled.
• Click the Inject Reactant button or click molecules inside the cylinder to drop Q below Kc and watch the forward reaction surge until equilibrium is restored.

1. 1Use Le Chatelier's principle to predict how a reversible gas reaction responds to changes in concentration, pressure/volume, and temperature.
2. 2Explain why compressing a gas mixture shifts equilibrium toward the side with fewer moles of gas molecules.
3. 3Distinguish between disturbances that change the reaction quotient Q (volume or concentration) and temperature changes that alter Kc itself.
4. 4Relate the macroscopic colour change of the N2O4 / NO2 gas mixture to the microscopic ratio of dimers to monomers.

Questions teachers ask