Where does the hydrogen and nitrogen for the haber process come from?
- nitrogen from air
- hydrogen from cracking oil fractions and natural gas
What are the conditions for the haber process?
- 200 atmospheres
- 450C
- iron catalyst
Why can’t the pressure be too high or low in the haber process?
- high pressure increases the percentage yield of a reaction
- but requires expensive material to handle the pressure and is dangerous
Why can’t the temperature be too high or too low in the haber process?
- high temperature, speeds up reaction and decreases the percentage yield
- low temperature slows reaction but increases yied
Why is a catalyst used in the haber process?
- to speed up the reaction
- which gets it to equilibrium proportions faster (catalyst doesn’t affect the position of equilibrium)
- without catalyst temperature would need raising
What do production costs depend on?
- price of energy
- cost of raw materials
- labour costs
- plant costs (equipment)
- rate of reduction
What does optimum conditions mean?
-condition that give the lowest production cost per kg of product
How does the price of energy affect the cost of production?
- industries need to keep energy bills low
- if reaction needs high temperature, running cost will be higher
How does the cost of raw materials affect the cost of production?
-keep this at a minimum by recycling un-reacted materials
How does the labour costs affect the cost of production?
- everyone working in the company needs payment
- labour-intensive process(i.e require many people) can be expensive
- automation cuts running costs by reducing the number of people involved
- companies must always weigh savings on wage bills against initial cost and running cost of machinery
How does the plant (equipment) cost affect the cost of production?
- cost of equipment depends on conditions it has to cope with
- equipment that can deal with very high pressures are more expensive than equipment needed to deal with atmospheric pressure
How does the rate of production affect the cost of production?
- the faster the rate of reaction the the less time and costs spent on production
- rates of reactions often increased by catalysts
- increase in production rate has to balance the cost of buying a catalyst and replacing any that get lost
What is meant by compromised conditions?
- optimum temperature that gives fast reaction rate and reasonable percentage yield
- its a compromise
What is the process of the haber process?
1-hydrogen and nitrogen enter at ratio of 3:1
2-heated at 450C, put under pressure at 200atm and catalysed by trays of iron in a reaction vessel
3-condenser at the bottom to condense the now ammonia into liquid
4-liquid ammonia is removed to stop reaction from reversing
4-the unused reactants stay as gases and are recycled
