Polymers

Question 1

Polymers

Answer 1

Covalent molecular substances of non metals bonded into molecules made by joining a large number of small molecules called monomers

Question 2

Bonds between monomers

Answer 2

Covalent bonds form between the monomer molecules to produce a polymer molecule

Question 3

Elements commonly found in polymers

Answer 3

Hydrogen, oxygen, chlorine and nitrogen

Question 4

Polymer advantages

Answer 4

all electrons are localised- will not conduct electricity therefore good electrical and thermal insulators
thermoplastics can be recyled
lightweight and easily moulded
corrosion resistant and chemically inert

Question 5

Co-polymer

Answer 5

Polymer made from more than one type of monomer

Question 6

Thermoplastic polymers

Answer 6

Generally quite soft and flexible- strong covalent bonds within monomer molecules but weak dispersion forces between the chains
soften when heated, allowing it to be reshaped and recycled

Question 7

Thermosetting polymers

Answer 7

Rigid
Have a covalent network structure with strong covalent bonds throughout the solid and strong forces within monomers and between chains
do not melt, cannot be reshaped, recycling is limited
elastomer
cross-linking

Question 8

Cross linking

Answer 8

joining the chains by covalent bonds

greater the number of cross-links, more rigid the polymer

Question 9

Elastomers

Answer 9

Polymers with special cross links which allow the polymer to stretch

Question 10

Polymerisation

Answer 10

Monomer molecules form polymer chains

Question 11

Condensation polymerisation

Answer 11

step-growth polymers, thermosetting polymers
Each monomer has a functional group at each terminus. Reaction occurs between two di-fuctional molecules
Leads to the formation of a covalent bond between the two monomers and elimination of a small molecule as the other reaction product(usually H2O, HCl)

Question 12

Addition polymerisation

Answer 12

Chain growth polymers
carbon-carbon double bonded monomers
empirical formula of polymer is same as monomer

Question 13

Polyethene

Answer 13

Simplest of polymers because only Hydrogen atoms are bonded to the atoms in the chain
it is a thermoplastic polymer

Question 14

Two different forms of polyethene

Answer 14

High density and low density

depends on the reaction conditions- temperature and pressure

Question 15

High density polyethene

Answer 15

Monomers join in continuous chains without any branches
Unbranched chains pack together quite closely
Hard, stiff, strong, able to be sterilised
Plastic bottles and fuel tanks

Question 16

Low density polyethene

Answer 16

Polymer chains are branched
Cannot pack together as closely as unbranched chain
Flexible and somewhat soft
Cling film and flexible water pipes

Question 17

Factors affecting polymer physical properties

Answer 17

Polarity of groups
type of polymer
polymer chain length
extent of branching
arrangement of groups
inclusion of additives like plasticisers

Question 18

Plasticisers

Answer 18

organic molecules that soften the plastic, by weakening intermolecular attractions

Question 19

Heteronuclear molecules

Answer 19

When the reactant (HX) is a heteronuclear molecule, the products are isomers.
Water is a heteronuclear molecule therefore the products are isomers

Question 20

Polyvinyl chloride

Answer 20

polychloroethene

Question 21

Cross linked polymer

Answer 21

Stiff, hard, strong, brittle, good electrical insulators, resists chemicals
tableware, knobs, handles and electrical insulation

Question 22

Why molar mass of a polymer always given as an average?

Answer 22

Linear polymers rarely have chains that are the same length so degree of polymerisation varies from chain to chain. Therefore when the molar mass of a polymer is calculated it will be an average of the values for the various chains

Question 23

Polymers disadvantages

Answer 23

made from non-renewable sources, aren’t biodegradable and cause evironmental risks
burn easily and give off toxic fumes
derived from crude oil which is a non renewable source
brittle at low temperatures
UV sensitive
deformed under mechanical load