This exam tips covers Exam Tips: Equilibrium 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 12 of 14 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 12 of 14
Practice
20 questions
Recall
15 flashcards
💡 Exam Tips: Equilibrium
🎯 Common Question Types:
- State what is meant by dynamic equilibrium (2 marks)
- Predict the effect of changing conditions using Le Chatelier (3 marks HT)
- Explain industrial compromise conditions for Haber process (4 marks)
- Count gas molecules to predict pressure effect (2 marks)
📝 Key Command Words:
- Predict: State direction of shift with reason
- Explain: Give the Le Chatelier mechanism and yield effect
- Evaluate: Weigh up yield vs rate vs cost for industrial conditions
⚠️ Common Mistakes to Avoid:
- Saying catalysts shift equilibrium — they don't (reach it faster)
- Confusing equal rates with equal concentrations
- Forgetting to count gas molecules for pressure questions
Quick Check: N₂ + 3H₂ ⇌ 2NH₃ (forward reaction is exothermic). What happens to the yield of ammonia if temperature is increased?
Increasing temperature shifts equilibrium in the endothermic direction (the backward reaction). This means the equilibrium position shifts to the LEFT, reducing the yield of ammonia. Although the rate increases, less ammonia is present at equilibrium.
Quick Check: For N₂ + 3H₂ ⇌ 2NH₃, what happens to the equilibrium position if pressure is increased?
Left side has 1 + 3 = 4 gas molecules. Right side has 2 gas molecules. High pressure shifts equilibrium to the side with fewer gas molecules — to the RIGHT (towards ammonia). Yield of ammonia increases.