Le Chatelier's Principle Simulator

Dynamic equilibrium shifts | HSC Chemistry Module 2

Reaction

Stress Controls

Change Concentrations

Presets

Equilibrium reached
N₂O₄(g) ⇌ 2NO₂(g)
N₂O₄
NO₂
K (equilibrium constant)
--
Q (reaction quotient)
--
Q vs K
Q = K
Direction
→ No shift

Concentration vs Time

Time Relative Concentration

Particle Counts

N₂O₄
0
NO₂
0
Reactants
0
Products
0
Ratio P/R: --

Conditions

Temperature
298 K
Pressure
1.0 atm
Total Moles
0
Catalyst
None

Theory: Le Chatelier's Principle

Le Chatelier's Principle Statement

If a dynamic equilibrium is disturbed by changing the conditions (concentration, temperature, or pressure), the position of equilibrium moves to counteract the disturbance.

Concentration Changes

Adding more reactant → shifts to products (right) to use up the added substance.

Adding more product → shifts to reactants (left) to use up the added substance.

Removing product → shifts to products (right) to replace what was removed.

Temperature Changes

For an endothermic forward reaction (ΔH > 0): increasing T shifts right (absorbs heat).

For an exothermic forward reaction (ΔH < 0): increasing T shifts left (opposes heating).

ln(K₂/K₁) = -(ΔH°/R)(1/T₂ - 1/T₁)

Pressure Changes

Increasing pressure shifts toward the side with fewer moles of gas.

Decreasing pressure shifts toward the side with more moles of gas.

Kp = Kc(RT)^Δn

Q vs K Relationship

Q < K: reaction proceeds forward (→) Q > K: reaction proceeds backward (←) Q = K: system at equilibrium

Catalyst Effect

A catalyst speeds up both forward and reverse reactions equally. It does NOT change the position of equilibrium or the value of K. It only helps equilibrium be reached faster.