What does NPK stand for?

nitrogen, phosphorus, potassium. They are the chemical symbols of the three elements.

Which compound supplies both nitrogen and potassium?

potassium nitrate. Its name contains both.

Which element does ammonium nitrate supply to plants?

nitrogen. Both the ammonium and the nitrate parts contain nitrogen.

Why are fertilisers used?

to increase crop yields. They replace nutrients that crops take out of the soil.

Which of these is used as a fertiliser?

ammonium phosphate. It supplies nitrogen and phosphorus.

Fertilisers · Cambridge IGCSE Chemistry (9

In plain words

Plants take nutrients out of the soil as they grow, and when a crop is harvested those nutrients leave the field with it. Fertilisers put them back. The three that matter most are nitrogen, phosphorus and potassium.

Three things to know

Fertilisers supply nitrogen (N), phosphorus (P) and potassium (K), so they are called NPK fertilisers.
Ammonium salts and nitrates are used as fertilisers: ammonium nitrate, ammonium phosphate, potassium nitrate.
Ammonium nitrate is made by neutralising nitric acid with ammonia.

Tips and tricks

NPK is just the three chemical symbols: N for nitrogen, P for phosphorus, K for potassium.
To see what a fertiliser supplies, read its name: potassium nitrate gives potassium and nitrogen.

5 questions, about 2 minutes.

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Fertilisers: 5 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

What does NPK stand for?
- nitrogen, protein, calcium
- nitrogen, phosphorus, potassium (the answer)
- nitrate, phosphate, carbonate
- sodium, phosphorus, potassium
They are the chemical symbols of the three elements.
Which compound supplies both nitrogen and potassium?
- ammonium nitrate
- potassium nitrate (the answer)
- calcium phosphate
- sodium chloride
Its name contains both.
Which element does ammonium nitrate supply to plants?
- nitrogen (the answer)
- phosphorus
- potassium
- calcium
Both the ammonium and the nitrate parts contain nitrogen.
Why are fertilisers used?
- to kill insects
- to kill weeds
- to increase crop yields (the answer)
- to make soil acidic
They replace nutrients that crops take out of the soil.
Which of these is used as a fertiliser?
- sodium chloride
- calcium carbonate
- ammonium phosphate (the answer)
- copper(II) sulfate
It supplies nitrogen and phosphorus.

5 questions

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Worksheet

3 questions, 5 marks. Write your answers on paper, then check them.

Fertilisers

Cambridge IGCSE Chemistry (9–1) 0971 · 5 marks · papermunch.org

Name ______________________________ Date ______________

Name the three elements supplied by NPK fertilisers.[1]
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Nitrogen, phosphorus and potassium.
I got this one
Name the acid and the alkali that react to make the fertiliser ammonium nitrate.[2]
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Nitric acid and ammonia (solution).
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Explain why farmers add fertilisers to the soil.[2]
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To replace the nutrients that crops have removed, so that the next crop grows well and gives a bigger yield.
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Answers: Fertilisers

1. Nitrogen, phosphorus and potassium.
2. Nitric acid and ammonia (solution).
3. To replace the nutrients that crops have removed, so that the next crop grows well and gives a bigger yield.