The Haber Process

Question 1

What does the haber process make ?

Answer 1

Ammonia

Question 2

Why is ammonia useful ?

Answer 2

Is a nitrogen based fertilizer which is useful in farming

Question 3

What is the equation for the Haber process ?

Answer 3

N2 + 3H2 — 2NH3
Iron catalyst

Question 4

What are the raw materials used in the haber process ?

Answer 4

Nitrogen and hydrogen

Question 5

What is the sources for the raw materials of the Haber process

Answer 5

Nitrogen: extracted from the air
Hydrogen: produced by reacting methane and steam

Question 6

What happens to the purified nitrogen and hydrogen !

Answer 6

Passed over an iron catalyst at 450*c and 200 atmosphere pressure

Question 7

What happens to the nitrogen and hydrogen when reacted ?

Answer 7

React to form Ammonia

Question 8

What is the reaction of the Haber process and what does this mean ?

Answer 8

The reaction is a reversible one meaning the ammonia produced (some) will break back down into nitrogen and hydrogen

Question 9

How do we increase the yield ? ( liquid)

Answer 9

We cool the ammonia to turn it into a liquid which is removed

Question 10

What happens at the end of the process ?

Answer 10

The unreacted nitrogen and hydrogen is recycled back over the catalyst

Question 11

How can we increase the yield ? ( pressure)

Answer 11

We can adjust the pressure and the temperature to shift towards the right hand side to produce more ammonia due to Le Chateliers principles

Question 12

What is the forward reaction in the Haber process ?

Answer 12

Exothermic so a relatively cool temperature will shift the equilibrium to the right hand side however this makes the reaction slow

Question 13

What is the compromise temperature ?

Answer 13

450*C which we get a relatively fast rate and relatively high yield of ammonia

Question 14

What is the iron catalyst used for ?

Answer 14

To increase the rate of reaction

Question 15

How does pressure affect the equilibrium ?

Answer 15

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

Question 16

What is the percentage of ammonia highest at between these temps 550,450 and 350 ?

Answer 16

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

Question 17

What are the pros and cons of using high pressure ?

Answer 17

Pros
- increased the percentage yield of ammonia
Cons
- expensive
- dangerous

So we settle on the compromise temperature of 200 atmosphere pressure

Question 18

What does the iron catalyst do ? ( key point)

Answer 18

Increase rate of reaction but doesn’t affect the position of the equilibrium