Uses of fertilisers and the Haber process

Fertilisers

In this chapter you will learn:

Fertilisers are chemicals that are added to the soil to increase crop production.
Fertilisers prevent future crops suffering from mineral deficiency.
Fertilisers are water soluble mineral that plants can absorb through the root.
Fertilisers improve the growth of crops.
The disadvantage of using too much fertilisers is that it can pollute water some time.
These fertilisers have plant nutrients, such as nitrogen, phosphorus, and potassium.
Ammonium nitrate, NH4NO3, is a salt used in fertilizers.
Ammonium nitrate is highly soluble in water
Ammonium ions, NH4+, and nitrate ions, NO3-, are important sources of soluble nitrogen.
Potassium chloride and potassium sulfate can be used as fertilisers because they contain potassium ions. Potassium chloride and potassium sulfate are obtained by mining.
Phosphate rock can be used to make fertilisers.

The Haber process is named after the German chemist, Fritz Haber. Ammonia is produced using the Haber process.
The raw materials for the Haber process are nitrogen and hydrogen.
In the Haber process: nitrogen and hydrogen are pumped through pipes.
The purified gases are passed over a catalyst of iron at a high temperature about 450°C and a high pressure about 200 atmospheres.
Some of the hydrogen and nitrogen reacts to form ammonia. The reaction is reversible; so, some of the ammonia produced breaks down into nitrogen and hydrogen.
When the mixture is cooled, the ammonia liquefies and it can be removed. Unreacted hydrogen and nitrogen are recycled.
The Haber process uses a catalyst to speed up the reaction. Because catalyst provides an alternative reaction pathway which has a lower activation energy.