Ch 20 - (Petrochemicals)

Question 1

What are polymers?

Answer 1

• Large molecules built by linking 50 or more smaller molecules called monomers
• repeat unit is connected to adjacent unit via covalent bonds

Question 2

What is an example of polymer?

Answer 2

PVC and nylon

Question 3

how is poly (ethene) formed?

Answer 3

Addition polymerization of ethene monomers

Question 4

What does addition of polymerization involve?

Answer 4

• Addition of many monomers to make a long chained polymer
• Many ethene monomers join together due to carbon carbon double bond breaking (C = C)

Question 5

Explain the addition of polymers.

Answer 5

• 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

Question 6

What are some other polymers made of?

Answer 6

• Addition of alkene monomers
• alkene monomers with different atoms attached to the monomer such as chlorine or a hydroxyl group.

Question 7

How is the name of a polymer deduced?

Answer 7

• 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

Question 8

How are polymer molecules?

Answer 8

Very large compared to most molecules

Question 9

What is used to display formula of polymers?

Answer 9

repeat units

Question 10

How do we draw a repeat unti?

Answer 10

• 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

Question 11

How do we deduce the monomer from the polymer?

Answer 11

• 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

Question 12

How is condensation polymer formed?

Answer 12

2 different monomers are linked together with the removal of a small molecule, usually water

Question 13

Hat is the difference between condensation polymer and addition polymer?

Answer 13

• addition polymerization forms the polymer molecule only
• condensation polymerization forms the polymer molecule and one water molecule per linkage

Question 14

What do monomers have?

Answer 14

• 2 functional groups, one on each end
• each monomer react with another end of monomer, creating a long chain of monomers

Question 15

What is a nylon?

Answer 15

• polyamide made from dicarboxylic acid (carboxylic with COOH group on either side)
• diamines (an amine with NH2 group at either end)

Question 16

How is nylon polymer formed?

Answer 16

Each COOH group reacts with another NH2 group on other monomers

Question 17

How is an amide linkage formed?

Answer 17

formed with a subsequent loss of one water molecule per link

Question 18

How is the structure of nylon represented?

Answer 18

drawing out the polymer using boxes to represent the carbon chain

Question 19

What is PET?

Answer 19

• polyethylene terephthalate
• polyester made up of dicarboxylic acid monomers (COOH group at either end) and diols (alcohols with OH group at either end)

Question 20

How is PET polymer formed?

Answer 20

each COOH group reacts with another OH group on another monomer

Question 21

How is an ester linkage formed?

Answer 21

• subsequent loss of one water molecule per link
• every ester linkage formed in condensation polymerization, one molecule of water is formed from the combination of a proton (H+) and hydroxyl ion (OH-)

Question 22

What is PET used in?

Answer 22

synthetic fibres sold under terylene

Question 23

How is the structure of PET represented?

Answer 23

drawing out polymer using boxes to represent carbon chain

Question 24

What is plastic made up of?

Answer 24

• Polymer
• chemically uncreative (non - biodegradable)

Question 25

How is incineration caused due to polymers being burnt?

Answer 25

• release heat energy
• produce CO2 (greenhouse gases)
• contributes to climate change
• release toxic fumes when burnt
• incinerated by incomplete combustion, carbon monoxide will be produced in a toxic gas

Question 26

What issues are caused due to polymer disposal?

Answer 26

1. Polluting oceans
2. Landfills

Question 27

What happens in polluting oceans when polymers are disposed?

Answer 27

Plastic accumulated in oceans causing huge disruption to marine

Question 28

What happens in landfills when polymers are disposed?

Answer 28

• sites fill up quickly
• take up valuable land

Question 29

What is PET (polyethylene terephthalate) used to make?

Answer 29

used to make plastic bottles

Question 30

What happens in condensation polymer with re - polymerisation?

Answer 30

• consisting of repeating ester units

Question 31

What are the conditions needed to recycle polymers?

Answer 31

Conditions:

• High pressures
• High temp
• degrade monomers making them re usable

Question 32

How is PET re - polymerised?

Answer 32

• easy to convert to monomers
• depolymerized using enzyme or chemical methods
• enzymes in microbes breakdown PET into original monomers
• same is achieved using solvents a mild catalyst and heating
• monomers are recovered and are re - polymerized into new PET
• saves on energy and resources

Question 33

What are proteins?

Answer 33

Example of condensation polymers

Question 34

How are proteins formed?

Answer 34

• from amino acid monomers joined together by amide links
• amino acids contain NH2 and COOH functional groups

Question 35

What are proteins also known as and why?

Answer 35

• due to containing amide links
• found in biological systems
• known as natural polyamides
• in protein the amide links are shown as peptide

Question 36

How is the structure in proteins?

Answer 36

• twenty common amino acids
• differing by side chain, represented by R

Question 37

How can the protein structure be represented?

Answer 37

boxes represent the carbon chain