Ch 20 - (Petrochemicals) Flashcards
1
Q
What are polymers?
A
- Large molecules built by linking 50 or more smaller molecules called monomers
- repeat unit is connected to adjacent unit via covalent bonds
2
Q
What is an example of polymer?
A
PVC and nylon
3
Q
how is poly (ethene) formed?
A
Addition polymerization of ethene monomers
4
Q
What does addition of polymerization involve?
A
- Addition of many monomers to make a long chained polymer
- Many ethene monomers join together due to carbon carbon double bond breaking (C = C)
5
Q
Explain the addition of polymers.
A
- Joins up many monomers with (C = C) bond
- one of the bonds in C=C breaks and forms a bond with the adjacent monomer
- polymer contains single bonds
6
Q
What are some other polymers made of?
A
- Addition of alkene monomers
- alkene monomers with different atoms attached to the monomer such as chlorine or a hydroxyl group.
7
Q
How is the name of a polymer deduced?
A
- name of the monomer in bracket
- adding poly - as prefix
- If propene is the alkene monomer used, same is poly (propene)
- poly ethene formed by addition of polymerization of ethene monomers
8
Q
How are polymer molecules?
A
Very large compared to most molecules
9
Q
What is used to display formula of polymers?
A
repeat units
10
Q
How do we draw a repeat unti?
A
- change the double bond in monomer to a single bond
- add a continuation bond to each end of repeat unit
- bonds on either side of polymer must be extended outside the brackets (called extensions or continuation bonds)
- small subscript n is written on bottom right hand side to indicate large number of repeat units
- Add on rest of the group in same order
11
Q
How do we deduce the monomer from the polymer?
A
- identify the repeating unit polymer
- change single bond in repeat unit to a double bond in monomer
- remove bond from each end of repeat unit
12
Q
How is condensation polymer formed?
A
2 different monomers are linked together with the removal of a small molecule, usually water
13
Q
Hat is the difference between condensation polymer and addition polymer?
A
- addition polymerization forms the polymer molecule only
- condensation polymerization forms the polymer molecule and one water molecule per linkage
14
Q
What do monomers have?
A
- 2 functional groups, one on each end
- each monomer react with another end of monomer, creating a long chain of monomers
15
Q
What is a nylon?
A
- polyamide made from dicarboxylic acid (carboxylic with COOH group on either side)
- diamines (an amine with NH2 group at either end)
