Haber process

Question 1

what is the Haber process used for

Answer 1

manufacture of ammonia

Question 2

list the 2 conditions and catalyst used in this process

Answer 2

• 450℃
• 200 atm
• iron

Question 3

why are 200atm pressures used

Answer 3

• a low pressure will favour the reverse reaction increasing the yield of reactants
• a high pressure will favour the forward reaction increasing yield of products
• however, high pressures can be dangerous and very expensive equipment is need hence the 200 atm compromise is made as products are being made safely and economically

Question 4

why is 450℃ used

Answer 4

• higher temperatures will favour the reverse reaction increasing yield of products as it takes in heat (is endothermic)
• a lower temperature will favour forward reaction increasing yield of products as it releases heat (is exothermic)
• however low temperature means a slow rate of reaction hence the 450℃ compromise is used as products will be made more quickly at a lower yield

Question 5

describe stage 1

Answer 5

H₂ and N₂ are obtained from air and natural gas and pumped into a compressor

Question 6

describe stage 2

Answer 6

the gases are compressed to about 200atm in the compressor

Question 7

describe stage 3

Answer 7

the pressurized gases are pumped into a tank containing layers of catalytic iron beds at a temperature of 450℃
some hydrogen and nitrogen react to form ammonia gas
N₂ + H₂ ⇋ 2NH₃

Question 8

describe stage 4

Answer 8

the unreacted hydrogen and nitrogen gas as well as ammonia are passed into a cooling tank. the ammonia is liquified and removed to pressurised storage vessels

Question 9

describe stage 5

Answer 9

the unreacted H₂ and N₂ are recycled back into the system and started over again