HSC Chemistry — Module 5
Haber Process — Flashcards & Quiz
The Haber process for synthesising ammonia is the canonical industrial application of equilibrium principles in HSC Chemistry Module 5. You need to justify each operating condition — high pressure, the temperature compromise, the iron catalyst, continuous removal of NH₃ — using Le Chatelier's principle. Top responses link the choices to economic and environmental trade-offs, not just yield. Be ready to write the equation, identify it as exothermic, and explain why a catalyst speeds equilibrium without shifting position.
Sample Flashcards
Q1: Describe the conditions used in the Haber process and justify each.
N₂ + 3H₂ ⇌ 2NH₃ (exothermic). Conditions: High pressure (~200 atm) → shifts right (4 mol gas → 2 mol). Moderate temperature (~450°C) → compromise between yield (lower T = higher yield) and rate (higher T = faster). Iron catalyst → faster equilibrium (doesn't change yield). Continuous removal of NH₃ → shifts right.
Q2: Why is ammonia (NH₃) important industrially?
Ammonia is primarily used to produce fertilisers (ammonium nitrate, urea — ~80% of NH₃ production). Also used in explosives, cleaning products, nylon production, nitric acid manufacture (Ostwald process), and refrigeration.
Sample Quiz Questions
Q1: The Haber process uses high pressure to increase the yield of ammonia.
Answer: TRUE
N₂ + 3H₂ ⇌ 2NH₃ has 4 moles of gas on the left and 2 on the right. High pressure (~200 atm) shifts equilibrium right, increasing NH₃ yield.
Q2: A very high temperature is used in the Haber process to maximise ammonia yield.
Answer: FALSE
The forward reaction is exothermic, so high temperature actually DECREASES yield. A moderate temperature (~450°C) is a compromise between yield (favoured at low T) and rate (faster at high T).
Q3: The iron catalyst in the Haber process increases the equilibrium yield of ammonia.
Answer: FALSE
The catalyst does NOT change equilibrium yield or Kc. It only speeds up the rate at which equilibrium is reached.
Related Concepts
Last updated: March 2026 · 2 flashcards · 4 quiz questions