unit 6 section 3 polymers

Question 1

explain condensation polymerisation

Answer 1

this involves two different types of monomer, each monomer has functional groups. the functional group of each monomer to form a link, creating a polymer chain.

Question 2

what are some examples of condensation polymers

Answer 2

polyamides, polyesters and polypeptides

Question 3

how are polyamides formed

Answer 3

they are formed by a reaction between dicarboxylic acids and diamines make polyamides.
this is done by the carboxyl groups from the dicarboxylic reacts with the amino groups of diamines to form amide links.

Question 4

what do amino acids contain

Answer 4

they contain an amine functional group and a carboxylic acid functional group.

Question 5

what happens in the hydrolysis of polyesters and polyamides

Answer 5

the ester or amide link in polyester and polyamides are broken by hydrolysis. the water molecules are added back and the links broken. the product of the reaction is a monomers that are used to make polymers and water.

Question 6

which polymers are stronger condensation polymers and addition polymers

Answer 6

condensation polymers are stronger and more rigid than addition polymers. this is because condensation polymers are made up of polar bonds, as well as induced dipole-dipole forces, there are permanent dipole - dipole forces and very strong hydrogen bonds between the polymer chains.

Question 7

how do you find out the repeating unit of a polyamide

Answer 7

• first draw out the two monomer molecules next to each other
• remove an OH from the dicarboxylic acid, and a H from one of the diamine - that gives you the water molecule
• join the C=O and the N together to make the amide link
• take a H of the other nitrogen atom, and an OH of the COOH group at the ends of your molecule.

Question 8

are polyalkanes chemically inert

Answer 8

yes , e.g. polyethene , polystrene

Question 9

why are polyalkanes chemically inert

Answer 9

this is because the repeating units are non-polar, so they are not susceptible to attacks by neuclophiles.

Question 10

give an example of using a chemically inert polymer

Answer 10

the polymer wont react with other things for example the polystyrene wont react with the coffee it is holding

Question 11

give a disadvantage of using a chemically inert polymer

Answer 11

the polymer is non - biodegradeable . the polymer cannot be hydrolysised and cannot break down naturally.

Question 12

explain why condensation molecules are biodegradeable

Answer 12

they are susceptible because the bonds can be broken by hydrolysis, this is because the bonds between repeating units are polar and are susceptible to attacks by nucleophiles such as water.
however the process is very slow

Question 13

what are the 4 ways of disposing of waste plastics

Answer 13

burying,burning recycling and reusing.

Question 14

what are the disadvantages of burying waste

Answer 14

• it requires areas of land
• as the waste decomposes it can release methane
• as the waste decomposes it can release toxins that can be washed away and contaminate water supplies

Question 15

give the disadvantages and advantages of burning polymers

Answer 15

adv - they can be burned to produce energy
dis- produces toxic gases - this has to be removed by passing them through a scrubber which neutralises by allowing them to react with a base.

Question 16

explain how plastics can be recycled

Answer 16

after sorting the plastics into different types, some can be melted and remolded, while others can be cracked into monomers which can be used to make other plastics or chemicals.

Question 17

what are the advantages and the disadvantages of recycling plastics

Answer 17

adv - saves raw material ( important as oil is non renewable ), the cost of recycling plastics is cheaper than making from scratch, produces less CO2 than burning the plastic
disadv - the plastic can be easily contaminated in the recycling process, it is technically difficult to recycle plastics, you cannot make the same plastic ( it has to be something new ) , it is more expensive than burning/landfill.