Push an equilibrium and watch it push back
"Push an equilibrium and watch it push back" is a free, interactive Class 11 Chemistry simulation for NEET and JEE, built on the lesson "Factors affecting equilibria: Le Chatelier's principle" in Equilibrium. Already at equilibrium: N₂ + 3H₂ ⇌ 2NH₃, ΔH = −92 kJ/mol. Tap a change. The graph jumps, then the reaction shifts until Q equals K again. Changing concentration or pressure shifts the position but leaves K alone; only temperature changes K (down on heating, for an exothermic reaction). A catalyst speeds both directions equally: equilibrium comes sooner, with exactly the same amounts. JEE Main asked 52 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Factors affecting equilibria: Le Chatelier's principle in Equilibrium. Change the values and watch what happens.
In JEE Main
42 shifts analysed
52 questions from Equilibrium across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT § "Factors Affecting Equilibria"
- Le Chatelier's principle: disturb an equilibrium by altering concentration, pressure or temperature, and the system responds by moving in whichever direction partly cancels that disturbance.
- Adding a reactant or removing a product shifts the equilibrium forward; the value of K does not change.
- Raising pressure by reducing volume shifts a gaseous equilibrium towards the side with fewer gas moles; if Δn = 0 pressure has no effect.
- Adding an inert gas at constant volume leaves the equilibrium unchanged, because the partial pressures and molar concentrations of the reacting gases stay the same.
- Temperature is the only factor that changes the value of K: for an exothermic reaction K falls as temperature rises; for an endothermic reaction K rises.
- For N₂O₄(g) ⇌ 2NO₂(g), which is endothermic, heating increases the brown NO₂ and cooling favours colourless N₂O₄.
- In the Haber process, N₂(g) + 3H₂(g) ⇌ 2NH₃(g) with ΔH = −92.38 kJ mol⁻¹, high pressure favours ammonia, and a moderate temperature with an iron catalyst balances yield against rate.
- A catalyst speeds up the forward and reverse reactions equally, so equilibrium is reached sooner but its composition and K do not change.
Questions
3 answers
- What does the "Push an equilibrium and watch it push back" simulation show?
- Already at equilibrium: N₂ + 3H₂ ⇌ 2NH₃, ΔH = −92 kJ/mol. Tap a change. The graph jumps, then the reaction shifts until Q equals K again.
- Does JEE Main ask questions from Equilibrium?
- Yes. JEE Main asked 52 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Factors affecting equilibria: Le Chatelier's principle" in Equilibrium (Class 11 Chemistry).
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