C4 Flashcards
What are plastics made up of?
Polymers
What are polymers?
Molecules formed when monomers are joined together.
To make polymers, high pressure and a catalyst are required
What are addition polymers made up of?
Made up of monomers which have a carbon-carbon double bond functional group.
What is condensation polymerisation?
2 different monomers with different functional groups which react together, forming bonds.
What are polymers held together by?
In polymers, all the atoms are held together by strong covalent bonds.
There are intermolecular forces between the chains
What are the properties of Low density polyethene?
Lots of space between polymer chains, so forces are weak
-This makes it flexible so it is used for plastic bags
What are the properties of High density polyethene?
Chains have strong forces of attraction, which makes it stronger and is used for watertanks.
What do polymers which only contain intermolecular forces have?
Contain individual tangled chains
- can slide over each other
- the forces between the chains can be overcome, so the polymers can be melted.
What are the properties of polymers with cross-links?
The chains are held together strongly.
- polymers don’t soften when heated
- strong, hard and stiff.
What are giant covalent structures?
Atoms bonded by strong covalent bonds
High melting and boiling points
Do not conduct
What is diamons?
Forms 4, strong covalent bonds
- very hard
- High melting point
- Doesn’t conduct as it has no free electrons
What is graphite?
Only forms 33 covallent bonds, creating sheets of carbon atoms.
- layers are held together by weak intermolecular forces so can be rubbed off each other.
- high melting point as covalent bonds are hard to break
- graphite can conduct as there are free eletrons
What is graphene?
A single sheet of graphine
What is an example of ionic bonding?
NaCl
What is an example of simple molecular bonding?
CO2