Lesson 11: NPK fertilisers Flashcards
Fill in gaps
Compounds of …….., ………. and ……….. are used as fertilisers to improve ……….. ………..
1.) nitrogen
2.) phosphorus
3.) Potassium
4.) Agricultural
5.) Productivity
What do NPK fertilisers contain compounds of?
- NPK fertilisers contain compounds of: nitrogen, phosphorus and potassium.
What are NPK fertilisers?
- NPK fertilisers are formulations of various salts: containing appropriate percentages of the elements.
How can industrial production of NPK fertilisers be achieved?
- Industrial production of NPK fertilisers can be achieved using a variety of raw materials in several integrated processes.
Name two compounds used to manufacture ammonium nitrate.
- Ammonia
- Nitric Acid
Which three compounds, that can be used in NPK fertilisers, are obtained by mining?
1.) Potassium chloride
2.) Potassium sulfate.
3.) Phosphate rock.
True or False
Phosphate rock can be directly used as feriliser.
- False.
- Phosphate rock cannot be directly used as fertiliser.
- Phosphate rock is treated with nitric acid/ sulphuric acid/phosphoric acid to produce soluble salts that can be used as fertilisers .
How are compounds of nitrogen produced to be used in NPK fertilisers?
- Ammonia is produced (The Harber Process.)
- Use ammonia to produce nitric acid.
- Add more ammonia to the nitric acid to form ammonium salts ammonium nitrate (used in NPK fertilisers.)
How are compounds of potassium produced to be used in NPK fertilisers?
- Mine potassium chloride/ potassium sulphate.
- These compounds can be used in NPK fertilisers without any further processing.
How is phosphate rock treated with nitric acid before it can be used in NPK fertilisers?
4 main steps….
1.) Phosphate rock + nitric acid produces phosphoric acid and calcium nitrate.
2.) Phosphoric acid contains phosphorous but cannot be added directly to plants.
3.) The phosphoric acid is neutralised with ammonia.
4.) This neutralisation reaction produced ammonium phosphate - which can be used in NPK fertiliser.
How is phosphate rock treated with sulphuric acid before it can be used in NPK fertilisers?
3 main steps….
1.) Phosphate rock + sulphuric acid produces a mixture of calcium phosphate and calcium sulfate.
2.) This mixture is called single superphosphate.
3.) The single superphosphate can be used in NPK fertilisers.
How is phosphate rock treated with phosphoric acid before it can be used in NPK fertilisers?
- Phosphate rock + phosphoric acid produces triple superphosphate.
- Triple superphosphate can be used in NPK fertilisers.
Compare the production of ammonium nitrate in school labs vs in industries.
(concentrations of reacting ammonia/ nitric acid comparison.)
- School lab: dilute solutions of ammonia and nitric acid –> makes substances safer to work with.
- Industries: Ammonia (gas form), nitric acid = concentrated. Very dangerous (as reaction is exothermic.) The heat has to be safely removed and used in later stages.
How is ammonium nitrate produces (in both schools and laboratries?) What type of reaction produces ammonium nitrate?
- Ammonium nitrate produced by reacting ammonia with nitric acid.
- This is a neutralisation reaction.
Compare the production of ammonium nitrate in school labs vs in industries.
(in terms of heat energy required to evaporate water.)
- SCHOOL LAB: Crystals produced using water bath and bunsen burner –> requires a lot of heat energy.
- Industry: some of the energy needed for evaporation is provided by the exothermic reaction itself (ammonia + nitric acid)
