haber process Flashcards
what is a use of ammonia
- making nitrogen - based fertilisers for farming
what is the equation for the haber process
N2 + 3H2 -><- ( IRON CATALYST ) 2NH3
( nitrogen + hydrogen -><- ammonia )
what are the raw materials for the haber process
- nitrogen and hydrogen
what is the sources for the raw materials
nitrogen = extracted from air
hydrogen = produced from reacting methane with steam
what temperature and pressure is the haber process conducted in
250 atm
450 degrees
what catalyst is used in the haber process
iron
what is released from the reaction
heat = exothermic reaction
what type of reaction is the haber process
reversible reaction
what are the steps in the haber process
- feed hydrogen and nitrogen into reaction vessel ( this is where the temperature is kept at constant 450 degrees and 250 atm ) where they are mixed together
- under these conditions some hydrogen and nitrogen react to form ammonia
- ammonia needs to be separated from nitrogen and ammonia , and since ammonia has a low boiling point , it is passed into a condenser where the gaseous ammonia is condensed to form liquid ammonia , whereas the nitrogen and hydrogen have high bioling points and so are passed out of condenser and recycled back into reaction vessel to react
why is a temprature of 450 degrees used
- because forward reaction is exothermic - a lower temperature is used to favour the forward reaction and achieve higher % yield
BUT TO HAVE A HIGHER YIELD A HIGHER TEMPERATURE IS NEEDED as particles need lots of kinetic energy to react = 450 is chosen as a compromise
why is a pressure of 200 atm used
- to have a higher yield a high pressure is needed as there are fewer molecules of product than reactant
- high pressure used so that high rate of reaction as particles collide more frequently
why is high presure not used
maintaining high pressure is expensive
can be dangerous - cause explosions = 200 atm is a compromise pressure
