The Haber and Contact processes
| English | Chinese | Pinyin |
|---|---|---|
| yield | 产率 | chǎn lǜ |
| Haber process | 哈伯法 | hā bó fǎ |
| ammonia | 氨 | ān |
| catalyst | 催化剂 | cuī huà jì |
| compromise | 折中 | zhé zhōng |
| Contact process | 接触法 | jiē chù fǎ |
Equilibrium that feeds the world
- These industrial processes balance yield 产率, rate and cost.
- They use Le Chatelier's principle to choose conditions.
- Both reactions are exothermic.
The Haber process combines nitrogen and hydrogen to make ______.
N₂ + 3H₂ ⇌ 2NH₃.
The Haber process 哈伯法
- Makes ammonia 氨: $\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3$ (exothermic).
- Conditions: about $450\,°\text{C}$, $200\ \text{atm}$, iron catalyst 催化剂.
- A low temperature would give more ammonia, but too slowly — so a moderate temperature is a compromise 折中.
Haber process yield: more ammonia at lower temperature and higher pressure
The Haber & Contact processes
compromise: yield vs rate
High pressure boosts yield; high temperature speeds it up but lowers yield — a compromise.
The Haber process makes:
The Haber process makes ammonia: N₂ + 3H₂ ⇌ 2NH₃ (exothermic).
Why is a moderate temperature (~450 °C) used in the Haber process?
The reaction is exothermic, so low temperature favours yield but is too slow; ~450 °C balances yield and rate.
High pressure increases the yield of ammonia in the Haber process because:
4 gas molecules become 2, so higher pressure shifts the equilibrium towards ammonia.
The Contact process 接触法
- Makes sulfur trioxide: $2\text{SO}_2 + \text{O}_2 \rightleftharpoons 2\text{SO}_3$ (exothermic).
- Conditions: about $450\,°\text{C}$, near $1$–$2\ \text{atm}$, vanadium(V) oxide catalyst.
Ammonia for fertiliser is made by the Haber process, a key equilibrium
The Contact process uses which catalyst?
The Contact process (2SO₂ + O₂ ⇌ 2SO₃) uses a vanadium(V) oxide catalyst.
Match each process to its facts.
Each item links the term to its correct meaning.
Why the compromise conditions
- The Haber process uses ~450 °C and ~200 atm: a compromise between yield, rate and cost.
- A lower temperature would give more ammonia but far too slowly.
You've got it
- both processes balance yield + rate + cost (Le Chatelier), and both are exothermic
- Haber: $\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3$; ~450 °C, 200 atm, iron catalyst (moderate temp = compromise)
- Contact: $2\text{SO}_2 + \text{O}_2 \rightleftharpoons 2\text{SO}_3$; ~450 °C, 1–2 atm, V₂O₅ catalyst