The haber process Flashcards
Give the chemical eqaution of the haber process
N2(g) + 3H2 (g) -> 2NH3 (g) (+ heat)
How are the reactants obtained:
- nitrogen
- hydrogen
Nitrogen is obtained from the air which is 78% nitrogen
Hydrogen is obtained from natural gases (methane) or cracking hydrocarbons
Why won’t all the nitrogen and hydrogen convert to ammonia
Because it is a reversilble reaction
What happens to reversible reactions?
They reach dynamic equilibrium
What are the three industrial conditions of the haber process?
Temperature
presure
catalyst
What is the temperature used in the haber process? Why (full explanation)?
450 degress celcius.
Because forming ammonia is an exothermic reaction so increasing the temperature would favour the reaction that formed nitrogen and hydrogen.
BUT a low temperature means a really slow rate of reaction so 450 is a compromise.
what happens to the unreacted nitrogen and hydrogen?
It is recycled through the reactor again.
what kind of reaction is the haber process?
exothermic because new bonds are being formed
What is the pressure used in the haber process, why?
200 atmospheres.
High pressure favour the forward reaction but building a reactor that contains and generates a high pressure would be really expensive. 200 is a compromise.
why does a high pressure favour the forward reaction?
Because there are less particles on the ‘ammonia being formed’ side (forward reaction) so the equilbrium shifts to favour the reaction that produces less particles.
what is the catalyst? Why is it used?
Iron
It makes the reaction go much faster but doesn’t affect the yeild.
How is ammonia removed from the reactor?
The ammonia is a formed as a gas, but as if cools in the condenser it liquefies and is removed to be stored at hig temperatures.
What process is ammonia also used in?
what does it make?
Ammonia is also used in the otswold process to make nitric acid. Ammonia can react with nitric to get ammonium nitrate. This is an especially good fertiliser
Why is ammonium nitrate an esspecially good fertiliser.
because it has nitrogen from two sources, the ammonia and the nitric acid.
