Unit 3-Fertilisers Flashcards
Which 3 essential elements do fertilisers provide to help healthy plant growth?
NPK
Nitrogen, phosphorus and potassium.
Why do fertilisers have to be soluble?
What problem can be caused if the fertiliser is too soluble?
Fertilisers must dissolve in water to be taken up by the roots.
Soluble fertilisers can be washed away by rainwater into rivers and lakes. This causes pollution resulting in fish dying and algal blooms (a green coating) covering water.
What is the name of the process which is crucial for making nitrogen containing fertilisers?
Haber process.
What chemical is produced by the Haber process?
Ammonia (NH3)
What are the two reactants for making ammonia by the Haber process?
Nitrogen (N2) and Hydrogen (H2)
What is the balanced equation for the Haber Process?
N2 + 3H2 ⇌ 2NH3
What does the ⇌ sign mean?
The reaction is reversible.
What conditions favour the production of ammonia in the Haber process?
Temperature-Moderate/Low temperature – reaction too slow: High temperature – ammonia decomposes.
Pressure-High- This increases the yield of ammonia.
What catalyst is used in the Haber process?
Iron is the catalyst for the Haber process.
Which chemical is made from ammonia by the Ostwald process and then used to make nitrate fertilisers?
Nitric acid.
What is the catalyst for the Ostwald process?
Platinum
