ammonia Flashcards
what is the Haber process?
Fritz Haber a German chemist devised a way of producing large amounts of ammonia from the reaction between nitrogen and hydrogen by changing the conditions to move equilibrium further to the right to speed up the reaction
what are the raw materials needed for the Haber process?
NITROGEN
HYDROGEN
where is the nitrogen obtained from?
AIR
where is the hydrogen obtained from?
natural gas or other sources
what happens to the gases?
- the nitrogen and hydrogen are purified
- then the nitrogen and hydrogen are passed over an iron catalyst
- at high temperatures approximately 450 degrees Celsius
- and at high pressures 200 atm
what does this process cause the gases to do?
some of the hydrogen and nitrogen react to form ammonia
What happens due to the reaction being reversible?
the ammonia breaks down again into nitrogen and hydrogen
what is the word equation for the Haber process?
Nitrogen + Hydrogen –>
what happens when the reaction is cooled?
ammonia liquefies and is removed
What happens to the remaining nitrogen and hydrogen?
It is RECYCLED
why is 450 degrees Celsius used?
It is a compromise temperature which allows a good yield to be made in quite a short time
why is 400 atm not used even though it produces a greater yield of ammonia?
it’s too high a pressure and too much energy would be required which is often obtained from fossil fuels. it’d be too dangerous and expensive (as stainless steel and other strong materials would be required)
what effect does the iron catalyst have on the percentage yield?
- it has no effect
what effect on cost of producing ammonia does the catalyst have?
- the rate of reaction is increased without an expensive increase in temperature or pressure (therefore energy cost is lowered)
