C15- The Haber Process Flashcards
What is produced by the haber process
The haber process produces ammonia
How is ammonia used
Ammonia is used in nitrogen based fertilisers for farming
What is the chemical equation for the haber process
The chemical equation for the haber process is
N2+3H2—>2NH3
Nitrogen + hydrogen —> ammonia
How can the raw materials for the haber process (Nitrogen and Hydrogen) be extracted
- Nitrogen can be extracted from the air
- Hydrogen can be produced by reacting methane with steam
What actually happens in the Haber process
1) In the haber process the purified nitrogen and hydrogen are passed over an iron catalyst at 450°C and 200 atmospheres pressure
2) This causes some of the nitrogen and hydrogen to react to form ammonia
What type of reaction is the haber process
The haber process is a reversible reaction as some of the ammonia breaks down into nitrogen and hydrogen
How do you increase the yield of ammonia
To increase the yield of ammonia , the ammonia is cooled to turn it into a liquid which is removed
What can be done with the unreacted nitrogen and hydrogen
The unreacted nitrogen and hydrogen can be recycled back over the iron catalyst
What temperature would be ideal for the Haber Process
- In the case of the Haber process the forward reaction is exothermic
- This means a relativley cool temperature will shift the reaction to the right hand side and more ammonia will be made ( if you decrease temperature then equilibrium will shift in the exothermic direction)
Why is a cool temperature not used
Although the cool temperature increases the yield of ammonia , it also makes the reaction too slow.
This means there is a trade off between rate of reaction and position of equilbrium (yield of ammonia )
What is selected as a compromise temperature for Haber process
450°C is selected as the compromise temperature for the haber process as you get a relativley fast rate of reaction and relativley high yield of ammonia
What is the role of the IRON catalyst in the reaction
The iron catalyst increases the rate of reaction but has no affect on the position of equilibrium
What pressure would be ideal for the Haber process
-For the haber process, a high pressure will push equilibrium to the right hand side and cause more ammonia to form (as ammonia is the side with the smaller number of molecules)
Why is a high pressure not used
-A high pressure is too expensive and dangerous to work with
What is decided upon as the compromise pressure
-200 atmospheres pressure is decided on as the compromise pressure as it is teh highest pressure possible without making the process to expensive and dangerous to work with
