Equilibria Flashcards
(30 cards)
What is a dynamic equilibrium?
A situation in which the composition of a constant concentration reaction mixture does not change because both forward and backward reactions are proceeding at the same rate and continuously.
What is ammonia used to make?
Mostly fertilisers like ammonium, nitrate, ammonium sulphate and urea.
Also synthetic fibres, dyes, explosives and plastics (polyurethane).
What process is used to make ammonia?
The Haber process.
What raw materials are used in the Haber process?
Air - provides N2
Water and natural gas (CH4) - provides H2
What conditions are used in the Haber process?
Pressure - 20,000 KPa (200 atmospheres)
Temperature - 670K
How is ammonia made?
Nitrogen and hydrogen are fed into a converter with a ratio of 1:3 and is passed over an iron catalyst (lumpy).
Any left over N2 or H2 is fed back into the converter.
Why is the iron catalyst used in the Haber process replaced every 5 years?
It gets poisoned due to impurities in the gas stream.
How is ethanol made?
Fermentation of sugars like glucose, using yeast as a catalyst.
Give the equation which shows the production of ethanol.
C6H12O6(aq) –yeast–> 2C5H5OH(aq) + CO2(g)
Glucose Ethanol
What is ethanol used for?
Alcohol, cosmetics, drugs, detergents, inks and motor fuels.
How is ethene obtained from crude oil?
Fractional distillation and then cracking.
What catalyst is used in the production of ethanol from ethene?
Phosphoric acid catalyst absorbed on silica.
Show the reversible reaction for the production of ethanol.
H2C=CH2(g) + H2O(g) 🔄 CH3CH2OH(g) 🔼H*=-46KJmol-
Ethene Ethanol
What conditions are used in the production of ethanol?
Pressure - 6500 KPa
Temperature - 570K
What are the problems with applying Le Châteliers principle to achieve a maximum yield in the reversible reaction for the production of ethanol?
- high pressure causes polymerisation if ethene, it is also expensive
- Low temperature causes a slow rate of reaction
- Too much steam dilutes the catalyst
What conditions are used in the production of Methanol?
Pressure - 1000kPa
Temperature - 500K
Catalyst - Copper
What is methanol used for?
Starting materials for chemical feedstock
Manufacture of methanal (formaldehyde)
Motor fuel
Why is methanol used as a motor fuel?
Methanol fires can be extinguished using water.
What is methanol made from?
Carbon monoxide and hydrogen using a copper catalyst.
What’s the symbol equation for the production of methanol?
CO(g) + 2H2(g) 🔄 CH3OH(g) 🔼H*=-91kJmol-1
What changes Kc?
Temperature
What conditions are used in the production of ethanol?
Temperature: 570K
Pressure: 6500kPa
What is methanol commonly used for?
Starting material for chemical foodstock
Used to make methanal (formaldehyde)
Why is methanol a good motor fuel?
Methanol fires can be put out with water, so they’re safer for cars.
