In I/GCSE Chemistry, we will learn about ammonia and green chemistry 4C --- Part 1.
Ammonia
Ammonia is used in fertilisers and explosives. There is a high demand for these stocks. This means that many industries have to ‘fix’ nitrogen into nitrogen compounds, in order to make the fertilisers and explosives.
Benefits of fertilisers
Less land is needed to grow crops ( food is manmade)--> supports towns + cities
Costs of fertilisers
Overuse of fertilisers-->Nitrogen is washed into seas-->algae is formed-->damaged ecosystems
The Haber process
Refer to I/GCSE Chemistry, industrial conditions required:
- Catalyst- Iron
- Pressure: x200
- Temperature: 450 degree Celsius
- Atom economy= 100% (all atoms are used up, there are no by-products).
- Yield= 15% BUT yield can be increased by recycling un-reacted hydrogen and nitrogen. This way, more ammonia is produced using the same amount of reactants.
When it comes to I/GCSE Chemistry, the reaction is reversible, but that doesn’t mean that all the hydrogen and nitrogen will be converted to ammonia- the gases don’t stay long enough in the vessel to reach equilibrium.
Synthesis of ammonia
- Air and natural gas are obtained
- - Air is processed-->nitrogen
- Natural gas is cracked-->hydrogen (+ CO, CO2 waste products)
3) Hydrogen and nitrogen go into the reactor; 450 degrees Celsius, catalyst, x200 pressure
4) - Gas is cooled in the condenser-->ammonia liquid
- Un-reacted hydrogen and nitrogen is recycled
Le Chateliers’ Principle
- A+B-->C+D = an equilibrium reaction
- In I/GCSE Chemistry, when you stress one side of an equilibrium reaction, the reaction will favour the side to relieve that stress.
- 4A + 4B--> C+ D = reaction is stressed on the A+B side because there is a higher conc. of it
- Le Chatelier’s principle states that the opposing side (C +D) will relive that stress in order to maintain equilibrium
- So, C+ D will take some of the A and the B in order to balance the reaction:
2A + 2B--> 2C + 2D = an equilibrium has been reached
- The concentration remains the same, but the distribution has changed.
- It has taken some of the reactants (A+B) and made it into products (C+D).
You finished part 1~~ you can proceed to part 2 now!!
