Do solids and liquids affect the shift?

Pure solids and liquids are omitted from the equilibrium expression; changing their amounts does not shift equilibrium.

Le Chatelier’s Principle Simulator

Q: Does adding an inert gas change equilibrium?

At constant volume, no change. At constant pressure, it can shift toward the side with more gas moles.

Q: Do catalysts shift equilibrium?

No—catalysts only change how fast equilibrium is reached, not the equilibrium position.

Predict how an equilibrium shifts when you change concentration, temperature, or pressure. Enter a balanced reaction (with phases), choose a stress, and see Left/Right/No shift with clear reasoning.

Background

Le Chatelier’s principle says a system at equilibrium will respond to a disturbance by shifting to partially counteract that change. This simulator uses your balanced equation, phase tags (e.g., H₂(g)), and reaction enthalpy (exo/endo) to predict qualitative shifts.

Enter reaction and select a stress:

Balanced Chemical Equation (use ⇌ or <=>)

Quick fill:

Reaction Enthalpy (overall):

Exothermic (ΔH < 0)

Endothermic (ΔH > 0)

Choose a stress to apply:

Concentration change

Species & Action:

Quick species:

Temperature change

Temperature:

Pressure / Volume change (gases)

Gas-phase stress:

Uses Δn_gas from your equation’s (g) tags.

Add inert gas

Condition:

Add catalyst

Result:

No results yet. Enter a reaction and choose a stress.

How to use the simulator

1) Type a balanced reaction with phases: e.g., N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g).
2) Choose exothermic or endothermic (overall).
3) Pick a stress (concentration, temperature, pressure/volume, inert gas, or catalyst).
4) Click Predict Shift to see Left/Right/No shift with reasoning.

Notes

Pressure/volume logic uses Δn_gas from the (g) tags in your equation.
Catalysts do not change equilibrium position—only the rate to reach it.
Pure solids/liquids don’t affect Q; changing their amounts doesn’t shift equilibrium.

Example Problems & Step-by-Step Solutions

Example 1 — Pressure increase

N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g), exothermic. Increase pressure (decrease volume).

Δn_gas = (2) − (1 + 3) = −2 (fewer moles on product side).
Higher pressure favors fewer gas moles → shift right (toward NH₃).

Example 2 — Temperature increase

Same reaction, exothermic. Increase temperature.

Treat heat as a product. Adding heat is like increasing a product.
System shifts to consume heat → shift left (toward reactants).

Frequently Asked Questions

Q: Does adding an inert gas change equilibrium?

At constant volume: no. At constant pressure: it can shift toward the side with more gas moles.

Q: Do catalysts shift equilibrium?

No. They only help the system reach equilibrium faster.

Q: Do solids and liquids matter?

Pure solids/liquids are omitted from Q; changing their amounts doesn’t shift equilibrium.