The Haber Process Flashcards
What does the haber process make ?
Ammonia
Why is ammonia useful ?
Is a nitrogen based fertilizer which is useful in farming
What is the equation for the Haber process ?
N2 + 3H2 — 2NH3
Iron catalyst
What are the raw materials used in the haber process ?
Nitrogen and hydrogen
What is the sources for the raw materials of the Haber process
Nitrogen: extracted from the air
Hydrogen: produced by reacting methane and steam
What happens to the purified nitrogen and hydrogen !
Passed over an iron catalyst at 450*c and 200 atmosphere pressure
What happens to the nitrogen and hydrogen when reacted ?
React to form Ammonia
What is the reaction of the Haber process and what does this mean ?
The reaction is a reversible one meaning the ammonia produced (some) will break back down into nitrogen and hydrogen
How do we increase the yield ? ( liquid)
We cool the ammonia to turn it into a liquid which is removed
What happens at the end of the process ?
The unreacted nitrogen and hydrogen is recycled back over the catalyst
How can we increase the yield ? ( pressure)
We can adjust the pressure and the temperature to shift towards the right hand side to produce more ammonia due to Le Chateliers principles
What is the forward reaction in the Haber process ?
Exothermic so a relatively cool temperature will shift the equilibrium to the right hand side however this makes the reaction slow
What is the compromise temperature ?
450*C which we get a relatively fast rate and relatively high yield of ammonia
What is the iron catalyst used for ?
To increase the rate of reaction
How does pressure affect the equilibrium ?
In the case of the Haber process a high pressure will push the equilibrium to the right hand side which increases the yield of Ammonia
What is the percentage of ammonia highest at between these temps 550,450 and 350 ?
350 because the reaction is at a relatively low temp however this decreases the rate and lowers the yield which is why we carry it out at 450
High temp also requires more energy so we use the compromise temperature of 450
What are the pros and cons of using high pressure ?
Pros
- increased the percentage yield of ammonia
Cons
- expensive
- dangerous
So we settle on the compromise temperature of 200 atmosphere pressure
What does the iron catalyst do ? ( key point)
Increase rate of reaction but doesn’t affect the position of the equilibrium
