- Created by: Sally Piggott
- Created on: 27-04-13 10:20
Nitrogen Fixation - Ammonia
Nitrogen fixation turns N2 from the air into ammonia:
1. Turns N2 into useful nitrogen compounds like ammonia.
2. The harber process is a non-biological way of fixing nitrogen.
3. Most of the ammonia produced by the harber process is used to make fertilisers.
4. Fertilisers are vital in the world food producttionas they increase crop yeild.
5. When used in largeamopunts though, fertilisers can pollute water supplies and cause eutrophication.
6. Eitrophication happens when fertilisers leak into rivers and lakes and it then stimulates rapid algal growth whi9ch then blocks light to the other plants and therefore other plants die. Dead microorganisms then feed on the dead plants, using up all the oxygen that aquatic animals need to survive.
7. Ammonia is also very important in industry where it is used to manufacture plastics, explosivess and pharmaceulticals.
Nitrogen Fixation - Catalysts
The efficiency of nitrogen fixation can be imoproved by catalysts:
1. In the harber proceess very high temps and pressures have to be used to turn nitrogen into hydrogen and ammonia.
2. Using an iron catalyst make the rate of reaction much faster
3. Without the catalyst the temp would had to be raised more even further to get a quick enough reaction and that would then have reduced the % yeild.
4. Some living organisms such as nitrogen-fixing bacteria can fix nitrogen at room temp and pressurre. They do this with enzymes.
5. Chemist would likle to be able to make catalysts that mimic these enzymes, so that the processes like the harber process can be carried out at room temp and presssure.
6. As it is expensive and time consuming to work at high temps and pressure, this would mean that rpocesses involving nitrogen fixation would become much cheaper and more efficient.
Nitrogen Fixation - Sustainable?
Is an nitrogen fixation a sustainabel process?
1. will the raw materials run out?
2. How good is the atom economy? - How much of the reacts mass will end up as useful products?
3. What do we do with the watse products?
4. What are the energy costs?
5. Will it damage the environment?
6. What are the health and safety risks?
7. Are there any benefits or risks for the society?
8. Is it pofitable?