Uses of Oil Flashcards
Why is cracking done?
Long-chain hydrocarbons aren’t as useful as smaller molecules.
What is cracking?
Splitting up long chain hydrocarbons into shorter alkane molecules and an alkene.
What kind of reaction is cracking?
Thermal decomposition.
How is cracking done?
- Vaporise hydrocarbon
2. Pass it over a powdered catalyst at about 400C-700C
What is the catalyst used in cracking?
Aluminium oxide.
What is an alkene?
A hydrocarbon with a carbon-carbon double bond.
Why are alkenes unsaturated?
They can make more bonds by opening up the double bond.
What are the test and result for an alkene?
Adding bromine water decolourises it.
Why is bromine water decolorised by an alkene?
The double bond has opened up to form bonds with the bromine.
What are the two methods of ethanol production?
- Hydration
2. Fermentation
How is hydration done?
Ethene is hydrated with steam in the presence of a catalyst.
Why is hydration a cheap process?
- Ethene is fairly cheap
2. Not much waste
What is the problem with hydration?
Ethene is non-renewable and will become expensive
What is the equation for fermentation?
Sugar –> Carbon dioxide + ethanol
What are the advantages of fermentation?
- Lower temperature
- Simpler equipment
- Renewable resource
- Cheap fuel for countries without oil
What are the disadvantages of fermentation?
- Not very concentrated - needs distillation
2. Needs purification
What is polymerisation?
Joining together lots of small alkene molecules to form very large molecules.
What are small alkene molecules also known as?
Monomers.
What are the conditions for polymerisation?
- Pressure
2. Catalyst
What do the properties of a polymer depend on?
- Material
- Temperature
- Pressure
What kind of polymers are used to make plastic bags?
Low density polyethene.
Give an example of a smart material.
Memory foam - gets softer as it heats up.
Why is it difficult to get rid of polymers?
Non-biodegradable - don’t rot.
Why will polymers get more expensive?
Crude oil resources are being used up.
