The table shows the percentage of ammonia in the equilibrium mixture for the reaction N2(g)+3H2(g)⇌2NH3(g)\mathrm{N_{2}(g) + 3H_{2}(g) \rightleftharpoons 2NH_{3}(g)}N2(g)+3H2(g)⇌2NH3(g) under different conditions.
| Pressure / atm | 300 ∘C300\,^\circ\mathrm{C}300∘C | 400 ∘C400\,^\circ\mathrm{C}400∘C | 500 ∘C500\,^\circ\mathrm{C}500∘C |
|---|---|---|---|
| 100 | 53 | 25 | 11 |
| 200 | 63 | 36 | 18 |
| 400 | 73 | 47 | 26 |
Statement 1: at every pressure, the percentage of ammonia at equilibrium decreases as the temperature increases
Statement 2: the data show that the forward reaction is exothermic
Statement 3: at each temperature, doubling the pressure doubles the percentage of ammonia at equilibrium
Which statements are correct?
1 only
1 and 2 only
2 and 3 only
1, 2 and 3
43 exam-style questions on Edexcel GCSE Chemistry 6.3 Dynamic equilibria, covering 6.3.1 The Haber process as a reversible reaction, 6.3.2 Conditions and rate in industrial equilibria, and 6.3.3 Fertilisers and the preparation of ammonium sulfate. Each one has a worked solution and a mark scheme showing where the marks go.