Fertilisers

Question 1

Three main essential elements in a fertiliser

Answer 1

nitrogen, phosphorus, potassium

Question 2

what happens if plants don’t get enough of these elements?

Answer 2

their growth and life processes are effected

Question 3

what do fertilisers do?

Answer 3

fertilisers replace these missing elements in the soil or provide more of them
this helps to increase crop yield as the crops can grow faster and bigger

Question 4

typical symptoms of nitrogen, N deficiency

Answer 4

poor growth

yellow leaves

Question 5

typical symptom of phosphorus, P deficiency

Answer 5

poor root growth

discoloured leaves

Question 6

typical symptom of potassium, K deficiency

Answer 6

poor fruit growth

discoloured leaves

Question 7

what is ammonia

Answer 7

ammonia is a base that can be neutralised by acids to make ammonium salts

Question 8

what do you get if you neutralise nitric acid with ammonia?

Answer 8

ammonium nitrate

Question 9

why is ammonium nitrate a good fertiliser?

Answer 9

has a high percentage of nitrogen

Question 10

Fertilisers

Answer 10

Ammonium sulfate, (NH4)2SO4
Ammonium phosphate, (NH4)3PO4
Potassium nitrate, KNO3

Question 11

what do you get if you neutralise sulfuric acid with ammonia?

Answer 11

ammonium sulfate

Question 12

what do you get if you neutralise phosphoric acid with ammonia?

Answer 12

ammonium phosphate

Question 13

what do you get if you neutralise nitric acid with potassium hydroxide?

Answer 13

potassium nitrate

Question 14

which method do you use to make fertilisers?

Answer 14

titration

Question 15

how to make fertilisers using titration (method)

Answer 15

1) using a pipette measure out a set volume of the alkali (ammonia or potassium hydroxide) into a flask
2) add a few drops of indicator (phenolphthalein or methyl orange)
3) fill burette with a standard solution (known concentration) of acid (nitric, sulfuric or phosphoric)
4) use the burette to slowly add the acid to the alkali. swirl the flask regularly.
5) the indicator changes colour when all the alkali has been neutralised (this is called the end point)
6) when the alkali has been neutralised you’ve got a fertiliser
7) the fertiliser isn’t pure - it still has indicator in it
8) to get pure fertiliser crystals note exactly how much acid it took to neutralise the alkali
9) repeat the titration using that volume of acid but no indicator
10) to get solid crystals - gently evaporate the solution (using a steam bath) until a little bit is left. leave to crystallise then filter out the crystals and leave them to dry