resources - the Haber process

Question 1

what is the Haber process for manufacture of ammonia?

Answer 1

nitrogen + hydrogen ⇌ ammonia
N2 + 3H2 ⇌ 2NH3
nitrogen can be extracted from air and hydrogen produced by reacting methane with steam.
purified nitrogen and hydrogen are passed over a iron catalyst at around 450 degrees and 200 atmospheres pressure. causes some nitrogen and hydrogen molecules to react and form ammonia. this is a reversible reaction so some ammonia breaks back down to nitrogen and hydrogen

Question 2

use of ammonia?

Answer 2

make nitrogen based fertilisers for farming

Question 3

how do we increase yield of ammonia made by Haber process?

Answer 3

cool the ammonia and turn it into a liquid which is removed. then recycle unreacted nitrogen and hydrogen back over the catalyst.

Question 4

how are conditions of Haber process chosen to increase yield of ammonia?
nitrogen + hydrogen ⇌ ammonia

Answer 4

involves Le Chatelier’s principal. (if system at equilibrium + a change is made to any of the conditions, then the system responds to counteract the change)

if we adjust temperature and pressure,equilibrium shifts towards the right hand side so more ammonia produced

Question 5

what is the forward reaction in Haber process for manufacture + what does this mean/how does temperature affect this? problem?

Answer 5

it is an exothermic reaction which means relatively cool temperature will shit equilibrium to the right hand side.
cool temperature makes reaction slow so have a trade off between rate if reaction + position if equilibrium so 450 degrees is a compromised temperature as we get a relatively fast rate of reaction and high yield of ammonia. iron catalyst also increases rate of reaction

Question 6

In the case if Haber process, how does high pressure affect equilibrium?

Answer 6

it will push to the right hand side.

Question 7

A ___ _________ reduces the rate. If we _________ the ____________, this increases the rate but __________ the _________. High temperatures require _____ _______

Answer 7

low temperature. increase, temperature, lowers, yield
more energy
- this is why we use comprised temperature of 450 degrees

Question 8

the percentage of ammonia increases at ____ _____ ________. however it is extremely _________ and _________ with very ____ pressures

Answer 8

very high pressures.
expensive and dangerous, high
- this is why we settle on pressure of 200 atmospheres

Question 9

The iron catalyst has __ ______ __ ___ on the position of the ___________

Answer 9

no effect at all, equilibrium