What are reactions called when they can go in both directions
Reversible reaction ()
What is a catalyst
Something that can speed up a reaction, and can be recovered at the end of the reaction
What is the Haber Process
The Haber Process creates ARTIFICIAL FERTILISERS, to supply nitrogen for the grain crops.
Nitrogen + hydrogen ammonia
N2 + 3H2 2NH3
How is the Haber Process made efficient
- using an iron catalyst
- a high pressure around 200 atmospheres
- temperatures around 450C
- a recycling system; not all the nitrogen and hydrogen react, so the nitrogen and hydrogen that didn’t react are sent sent back to the reaction vessel (start of the reaction)
Why is the percentage yield for ammonia in the Haber Process not any higher or lower
- high pressure INCREASES percentage yield; even higher pressures could be used
- high temperature DECREASES percentage yield, however it makes the reaction faster
- 450C is OPTIMUM temperature; the yield isn’t as good but the yield is made faster, so produces more ammonia in a day
- catalysts don’t affect the yield; they make the reaction go faster
What affects the cost of making ammonia
- the cost of building the plant in the first place
- the labour costs; paying people wages
- the cost of the chemicals; hydrogen and nitrogen
- the energy costs
- how fast the reaction will go; the catalyst makes it go faster, so more ammonia can be made, but the catalyst itself costs money
What is ammonia used for
-it was originally created to make explosives
Now:
-over 80% of all ammonia goes into fertilisers
-ammonia is used to make nitric acid; which goes into more fertilisers
-very small amounts of ammonia are used to make household cleaners
What is the formula for ammonia, how is it made, and where do these elements come from
- NH3
- joining nitrogen and hydrogen
- nitrogen comes from the air
- hydrogen is made from natural gas or by cracking oil fractions
