C15 Flashcards
Manure used to be used as
Fertilisers
Formulated fertilisers are better than manure
As they are more widely availabke, easier to use, don’t smell and have just enough of each nutrient so more crops can be grown
NPK fertilisers are
Formulations containing salts of nitrogen (N), phosphorus (P), potassium (K)
The three main essential elements in fertilisers are
Nitrogen, phosphorus and potassium
If plants don’t get enough of NPK,
Their growth and life processes are affected. These elements may be missing from the soil if they’ve been used up bu previous crop
Fertilisers replace missing elements or provide more of them.
This helps to increase crop yield, as the crops can grow faster and bigger.
Ammonia can be reacted wit oxygen and water in a series of reactions to make
Nitric acid
Phosphate and Potassium are sourced from mined compounds
- Potassium chloride and potassium sulphate can be mined and used as a source of potassium.
- Phosphate rock is also mined. However, because the phosphate salts in the rock are insoluble.
Reacting Phosphate rock with a number of different types of acuds produces soluble phosphates:
- Reaction with nitric acud produces phosphoric acid and calcium nitrate.
- Reaction with sulfuric acid produced calcium sulfate and calcium phosphate.
- Reaction with phosphoric only produces calcuim phosphate.
What are the two sources of most of the salts in NPK Fertilisers
Mined
Manufactured by reacting acids with bases
Why can phosphate rock not be used as a fertiliser
Insoluble in water
Ammonia is used to produce nitrogen-containing compounds:
In industry:
The reaction is carried out in giant vats, at high concentrations resulting in a very exothermic reaction.
The heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate product
