How the Haber plant runs, how the equilibrium responds to changes (Higher), percentage yield, and making NPK fertilisers in industry and in the lab, with the nitrogen worked out per bag and per pound.
What you will learn
- Describe the Haber process and why unreacted gases are recycled
- Predict how temperature, pressure and a catalyst affect the equilibrium (Higher)
- Calculate a theoretical mass and a percentage yield (Higher)
- Work out the percentage of nitrogen in a fertiliser or blend and compare value
The Haber plant
nitrogen + hydrogen ⇌ ammonia
N₂ + 3H₂ ⇌ 2NH₃ (forward reaction exothermic)
- Raw materials: nitrogen from the air; hydrogen usually from natural gas. They are purified (impurities would poison the catalyst) and fed in at 1 volume of nitrogen to 3 of hydrogen.
- The gases pass over an iron catalyst at about 450 °C and 200 atmospheres.
- The mixture is cooled: ammonia liquefies and is removed. Unreacted nitrogen and hydrogen are recycled.
- Most ammonia is used to make fertilisers.
The rest of this lesson and its 10 practice questions are locked.
In this lesson
- The Haber plant
- Moving the equilibrium (Higher)
- NPK fertilisers
- Try it: Read the table, then the compromise
10 practice questions, marked as you go; about 30 minutes in all.
Key terms
Iron catalyst
In this unit: Using resources
Making water potable and the water practical, life cycle assessments and recycling, phytomining and bioleaching, corrosion and materials, and the Haber process with NPK fertilisers, with every calculation worked.