The Haber Process and NPK fertilisers C15
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- Created by: person_one
- Created on: 05-09-22 14:02
Name a use for ammonia
It is used to produce nitrogen-based fertilisers.
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What is the Haber process be used for?
The Haber process is used to manufacture ammonia
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What are the raw materials for the Haber process?
Name a source of these raw materials
Name a source of these raw materials
Nitrogen and hydrogen
Nitrogen - extracted from air
Hydrogen - produced by reacting methane with steam/ natural gas
Nitrogen - extracted from air
Hydrogen - produced by reacting methane with steam/ natural gas
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What is the equation for the Haber process?
nitrogen + hydrogen ⇌ ammonia
N₂ + 3H₂ ⇌ 2NH₃
N₂ + 3H₂ ⇌ 2NH₃
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What happens during the Haber process?
The purified gases passed over iron catalyst at a high temp+high pressure. Some hydrogen + nitrogen reacts to form ammonia. On cooling, ammonia liquefies + is removed. Reaction = reversible so some ammonia breaks down again into nitrogen and hydrogen.
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What happens to the remaining hydrogen and nitrogen?
The unreacted hydrogen and nitrogen is re-cycled back over the catalyst.
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What temp is used during the Haber process and why?
An optimum temperature of 450OC is used. Using a lower temperature would give a higher yield but the rate would be too slow.
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Explain the temp used in terms of Le Chatelier's Principle
The forwards reaction of the Haber process is exothermic, so a cooler temp will shift the equilibrium to the right hand side (but a cool temp makes the reaction slow). We have a trade-off between rate of reaction and position of equilibrium. 450C is a com
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What pressure is used during the Haber process and why?
A pressure of 200 atmospheres is used. Using a higher pressure would give a higher yield but would be too expensive because the cost of energy to produce the pressure would be high.
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Explain the pressure used in terms of Le Chatelier's Principle
In the Haber process, a high pressure will push the equilibrium to the right hand side.
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Why is a catalyst used in the Haber process?
The catalyst speeds up the rate of reaction and saves money by allowing a lower temperature to be used.
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What other way is money saved in the Haber process?
The recycling saves money because no raw materials are wasted.
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What do NPK fertilisers contain?
Compounds of nitrogen, phosphorus and potassium (these are often used to improve agricultural productivity.)
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How can industrial production of NPK fertilisers be achieved?
By using a variety of raw materials in several integrated processes.
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NPK fertilisers are __________ of various ______ containing appropriate ____________ of the elements.
NPK fertilisers are FORMULATIONS of various SALTS containing appropriate PERCENTAGES of the elements.
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What is the main compound of nitrogen in NPK fertilisers and how is it made?
Main compound is ammonium nitrate (NH₄NO₃)
To make this, we use ammonia (which is produced by Haber process). We then use the ammonia to produce nitric acid. We react nitric acid + ammonia to make ammonium nitrate
To make this, we use ammonia (which is produced by Haber process). We then use the ammonia to produce nitric acid. We react nitric acid + ammonia to make ammonium nitrate
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Where does the potassium in NPK fertilisers come from?
Where do these compounds come from?
Where do these compounds come from?
It comes from the salts potassium chloride or potassium sulfate
They are both mined from the ground and can be used directly without further processing
They are both mined from the ground and can be used directly without further processing
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Phosphate rock has to be __________ ___________ before being used in fertilisers.
Phosphate rock has to be CHEMICALLY PROCESSED before being used in fertilisers.
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Phosphate rock is treated with _____ acid or _______ acid to produce soluble _____ that can be used as fertilisers.
Phosphate rock is treated with NITRIC acid or SULFURIC acid to produce soluble SALTS that can be used as fertilisers.
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How is phosphate rock treated with nitric acid?
Treating phosphate rock with nitric acid produces phosphoric acid and calcium nitrate. Phosphoric acid contains phosphorus, but we cannot add this directly to plants, so we neutralise it with ammonia. This produces ammonium phosphate which can be used in
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How is phosphate rock treated with sulfuric acid?
Treating phosphate rock with sulfuric acid produces a mixture of calcium phosphate and calcium sulfate. This mixture is called single superphosphate. This can be used in NPK fertilisers
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How is phosphate rock treated with phosphoric acid?
Treating phosphate rock with phosphoric acid produces triple superphosphate. This can be found in NPK fertilisers
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Compare the safety of production of fertilisers in industry and in a lab eg at school
Lab- dilute solutions of ammonia/nitric acid used so its safe to work w
Industry- ammonia used as a gas, nitric acid=conc. - ↑ dangerous, as reaction = exothermic. Heat produced has to be safely removed, and it is then used in later stages
Industry- ammonia used as a gas, nitric acid=conc. - ↑ dangerous, as reaction = exothermic. Heat produced has to be safely removed, and it is then used in later stages
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Compare the use of heat energy in production of fertilisers in industry and in a lab eg at school
Lab- we produce crystals using a water bath+Bunsen burner, which requires lots of heat energy
Industry- some of the energy for evaporation is provided by the exothermic reaction earlier
Industry- some of the energy for evaporation is provided by the exothermic reaction earlier
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Compare the amount of ammonium nitrate in production of fertilisers in industry and in a lab eg at school
Lab- only small amount of ammonium nitrate can be produced in one go (batch process)
Industry - chemical is produced by a continuous process so thousands of kg can be produced easily
Industry - chemical is produced by a continuous process so thousands of kg can be produced easily
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Other cards in this set
Card 2
Front
What is the Haber process be used for?
Back
The Haber process is used to manufacture ammonia
Card 3
Front
What are the raw materials for the Haber process?
Name a source of these raw materials
Name a source of these raw materials
Back
Card 4
Front
What is the equation for the Haber process?
Back
Card 5
Front
What happens during the Haber process?
Back
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