In this I/GCSE Chemistry blog post, we will be looking at how ammonia is collected and the features of this substance.
HOW TO OBTAIN AMMONIA - THE HABER PROCESS
- The raw materials for this process are hydrogen and nitrogen.
- Hydrogen is obtained by reacting natural gas - methane - with steam, or through the cracking of oil.
- Nitrogen is obtained by burning hydrogen in air.
- When hydrogen is burned in air, the oxygen combines with the hydrogen, leaving nitrogen behind.
Nitrogen and hydrogen will react together under these conditions:
- a high temperature - about 450ºC
- a high pressure - about 200 atmospheres (200 times normal pressure)
- an iron catalyst
The reaction is reversible:
Nitrogen + hydrogen = ammonia
N2(g) + 3H2(g) = 2NH3(g)
- The flow chart shows the main stages in the Haber process.
- The reaction mixture is cooled so that the ammonia liquefies and can be removed. The remaining nitrogen and hydrogen are recycled.
PROPERTIES OF AMMONIA
- colourless gas with sharp smell
- lighter than air
- very soluble in water; the resulting solution contains ammonium and hydroxide ions
- an alkaline gas - turns damp red litmus blue, due to its hydroxide ions
- puts out a burning splint - won't burn in air but will in pure oxygen - greenish yellow flame
Ammonia is so soluble in water that it can be made to perform a ‘fountain’ experiment.
- A bottle of ammonia gas is fitted with a stopper with a glass tube passing through it.
- The bottle is inverted so that the tube can dip into water in which some red litmus has been dissolved.
- The ammonia dissolves in water and creates a reduced pressure in the bottle, so that more water is sucked into it.
- The red litmus turns blue as it fountains into the top vessel.
The ammonium ion NH4+ is not capable of independent existence. It always accompanies a negative ion. In the case of ammonium hydroxide, the negative ion is hydroxide, OH .
- All common ammonium compounds are white, ionic solids which are soluble in water.
That is all!
References:
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.chemguide.co.uk%2Fphysical%2Fequilibria%2Fhaber.html&psig=AOvVaw16menpgfOPOjneD2b6DjhV&ust=1628218287425000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCNiazffvmPICFQAAAAAdAAAAABAD
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.quora.com%2FWhat-is-the-fountain-experiment-of-ammonia&psig=AOvVaw2EfvhYwzAwJdgz8bYTH-Wh&ust=1628218424026000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCOC-grrwmPICFQAAAAAdAAAAABAD
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.123rf.com%2Fphoto_66358964_ammonia-fountain-experiment-to-demonstrate-the-solubility-of-ammonia-gas-fully-labelled-diagram.html&psig=AOvVaw2EfvhYwzAwJdgz8bYTH-Wh&ust=1628218424026000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCOC-grrwmPICFQAAAAAdAAAAABAQ
Drafted by Venetia (Chemistry)