Other Useful Substances from Crude Oil Flashcards
(29 cards)
How are hydrocarbons cracked?
Heating them until they vaporise
Passing them over heated catalyst
Causes thermal decomposition reaction to take place
What happens when hydrocarbons are cracked?
Long chained hydrocarbons become shorter chains
Requires heat
Produces an alkane and an alkene
What are alkenes?
Unsaturated hydrocarbons
Have double bond
What do all alkenes end with?
-ene
What is the general formula for an alkene?
C(n) H(2n)
Draw the display formula for ethene
Sorry can’t put it on here without a lot of effort
What are alkenes useful for?
Making other molecules especially polymers
How can you distinguish between alkenes and alkanes?
Reacting them with orange bromine water
Alkenes turn it colourless
What is polymerisation?
Small alkenes join together to form long-chain molecules (polymers)
What does the properties of a polymer depend on?
What they are made from
Conditions they are made in
What are small alkene molecules called?
Monomers
Why can monomers be joined easily?
Their bonds are easily broken
How can polymerisation be represented?
Look in the book
What is the general equation for polymerisation?
You should really be getting the message by now
What is polyvinyl chloride often used for?
Waterproof items
Drain pipes
As an electrical insulator
What is polystyrene often used for?
Castings for electrical appliances
Expanded to make protective packaging
What is poly(ethene) often used for?
Plastic bags and bottles
What is poly(propene) often used for?
Crates
Ropes
How are polymers and composites being used in medicine and dentistry?
Implantable materials for tissue surgery
Dental cements and fillers
Hydrogels used as wound dressing
Silicone hydrogel contact lenses
What does biodegradable mean?
Broken down by microbes therefore biodegradable materials decompose and rot away
What happens if plastics are burnt?
They produce air pollution
Some produce toxic fumes
Way is the biggest problem with most plastics?
They are not biodegradable
Why are plastics recycled?
To reduce the amount sent to landfill sites
How are scientists trying to overcome the problem of non biodegradable plastics?
By making biodegradable polymers
