Le Chatelier's Principle (Higher Tier)
Part of Equilibrium (HT) — GCSE Chemistry
This higher tier covers Le Chatelier's Principle (Higher Tier) within Equilibrium (HT) for GCSE Chemistry. Revise Equilibrium (HT) in Rates of Reaction for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 4 of 14 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.
Topic position
Section 4 of 14
Practice
20 questions
Recall
15 flashcards
🎓 Le Chatelier's Principle (Higher Tier)
"If a system at equilibrium is disturbed, it will shift in the direction that opposes the change."
Effect of changing CONDITIONS:
🌡️ TEMPERATURE
Increase temperature → equilibrium shifts in the ENDOTHERMIC direction (absorbs the extra heat)
Decrease temperature → equilibrium shifts in the EXOTHERMIC direction (releases heat to compensate)
System tries to "use up" or "release" the extra heat
🧪 CONCENTRATION
Increase concentration of a reactant → shifts to PRODUCTS (right)
Increase concentration of a product → shifts to REACTANTS (left)
System tries to "use up" the added substance
💨 PRESSURE (gases only)
Increase pressure → shifts to side with FEWER gas molecules
Decrease pressure → shifts to side with MORE gas molecules
System tries to reduce the change in pressure
What about catalysts?
Catalysts do NOT change equilibrium position — they just help reach equilibrium faster by speeding up BOTH forward and backward reactions equally.
Quick Check: A student adds a catalyst to a reversible reaction at equilibrium. Explain whether the position of equilibrium shifts.
The position of equilibrium does NOT shift. A catalyst speeds up both the forward AND the backward reactions equally, so the ratio of products to reactants at equilibrium remains the same. The system simply reaches equilibrium faster. This is an important distinction — catalysts increase the rate of reaching equilibrium, but do not change where equilibrium lies.