6.3 Equilibrium reactions in industry Flashcards
What method is used to make ammonia made in industry
. React nitrogen and hydrogen together in a reversible reaction which is exothermic forward.
. This happens in the HABER process
. The nitrogen and hydrogen are fed into a converter, and an iron catalyst is used
Where does the nitrogen and hydrogen come from for the reaction to make ammonia
Nitrogen comes from air
Hydrogen comes from the natural gas methane in the reaction:
CH4 + H2O –> CO + 3H2
What is ammonia used for
Fertilisers eg ammonium nitrate, ammonium sulfate and urea
Some can also make plastics, explosives and synthetic fibres eg nylon
What are the ideal conditions for making ammonia
. Iron catalyst which is solid in pea sized lumps to increase surface area so the nitrogen and hydrogen can flow over it continuously
The catalyst has to be replaced every 5 years because of catalytic poisoning
. Low pressures and high temperatures give maximum conversion
How is ethanol produced
What is the reaction
. Fermentation of sugars eg glucose with the enzymes in yeast as a catalyst
C6H12O6 –> 2C2H5OH +2CO2
It is made by adding water to ethene (so it is a hydration reaction)
. A catalyst used is phosphoric acid absorbed on silica
. Reaction is reversible
Uses of ethanol
Where does the ethene come from
. Makes alcoholic drinks
. In cosmetics, drugs, detergents, inks and motor fuel
Main source of ethanol is ethene from crude oil obtained by fractional distillation then cracking
What conditions of the reaction will produce the maximum yield of ethanol from ethene
CH2=CH2 + H2O –> CH3CH2OH
ΔH is -46
. A high pressure which will move the equilibrium to the right as there are fewer molecules there
. A low temperature will move equilibrium to the exothermic side to release more heat
. Excess steam will force equilibrium to the right to reduce the steam concentration
What are some practical problems with the production of ethanol
. High pressure causes ethene to polymerise to make polyethene
. High pressure is expensive so increases the cost of building the plant and the energy costs of running it
. Low temperature will reduce the rate of reaction and therefore how quickly equilibrium is reached
. Too much steam dilutes the catalyst
How is methanol produced
. Made as chemical feedstock , so is a starting material for making other chemicals
. It is made in reaction
CO(g) + 2H2(g) –> CH3OH(g). ΔH=-91
A copper catalyst is used
Methanol can be used as a motor fuel
How would the highest yield of methanol be produced
. A highest yield will be given at a low temperature and high pressure
