14.3 Polymers Flashcards
What are polymers?
Polymers are large molecules built by linking 50 or more smaller molecules called monomers
What are the repeating units connected to each other by?
Each repeat unit is connected to the adjacent units via covalent bonds
What are homopolymers?
homopolymers contain just one type of unit
What are 2 examples of homopolymers?
polythene and polychloroethene, commonly known as PVC
What are copolymers?
Others contain two or more different types of monomer units and which are called copolymers
What are 2 examples of copolymers?
Examples include nylon and biological proteins
Do all polymers have the same linkages?
NO
Different linkages also exist, depending on the monomers and the type of polymerisation
What are 3 examples of linkages?
Examples of linkages are covalent bonds, amide links and ester links
What are examples of synthetic polymers?
Plastics, nylon and terylene
What type of polymer is nylon?
Nylon is a copolymer
How is nylon used?
used to produce clothing, fabrics, nets and ropes
What type of polymer is terylene?
Terylene is a polyester
What is terylene made from and what joins it together?
made from monomers which are joined together by ester links
How is terylene used?
Terylene is used extensively in the textile industry and is often mixed with cotton to produce clothing
What are 3 examples of plastics?
poly(e)thene
polypropene
polychloroethene
What is the repeating unit for polythene?
|~ H H ~|
| | | |
-- |---C--C---| --
| | | |
|_ H H _| nWhat is the repeating unit for polypropene?
|~ CH3 H ~| | | | | -- |---C-----C---| -- | | | | |_ H H _| n
What is the repeating unit for polychloroethene? PVC
|~ H Cl ~| | | | | -- |---C--C---| -- | | | | |_ H H _| n
What are uses of polythene?2
- plastic bags (low density polythene)
- plastic bottles (high density polythene)
What are uses of polypropene? 3
- food packaging
- ropes
- carpets
What are uses of polychloroethene? 4
- plastic sheets
- artificial leather
- drainpipes and gutters
- insulation on wires
What are non-biodegradable plastics?
These are plastics which do not degrade over time or take a very long time to degrade, and cause significant pollution problems
Where is plastic pollution the biggest problem?
In particular plastic waste has been spilling over into the seas and oceans
Why is it a problem when plastic gets into oceans?
it causes huge disruptions to marine life
What problems do non-biodegradable plastics cause in landfills?
In landfills waste polymers take up valuable space as they are non-biodegradable so microorganisms cannot break them down.
This causes the landfill sites to quickly fill up
What problems do non-biodegradable plastics cause when they are incinerated? (complete combustion)
Polymers release a lot of heat energy when incinerated and produce carbon dioxide which is a greenhouse gas that contributes to climate change
What problems do non-biodegradable plastics cause when they are incinerated? (incomplete combustion)
If incinerated by incomplete combustion, carbon monoxide will be produced which is a toxic gas that reduces the capacity of the blood to carry oxygen
Why can polymers not be simply recycled?
Polymers can be recycled but different polymers must be separated from each other which is a difficult and expensive process
How are addition polymers formed?
Addition polymers are formed by the joining up of many monomers
In what monomers can addition polymerisation occur?
only occurs in monomers that contain C=C bonds
- what bonds are broken during addition polymerisation?
addition polymerisation
One of the bonds in each C=C bond breaks
- After the C=C bonds are broken, what new ones are formed?
addition polymerisation
forms a bond with the adjacent monomer
- What bonds does the polymer have?
addition polymerisation
the polymer being formed containing single bonds only
- What are polymers usually made of?
addition polymerisation
Many polymers can be made by the addition of alkene monomers
- if the polymer is not made of alkene monomers, what can it be made of?
addition polymerisation
Others are made from alkene monomers with different atoms attached to the monomer such as chlorine or a hydroxyl group
- How is the name of a polymer deduced?
addition polymerisation
The name of the polymer is deduced by putting the name of the monomer in brackets and adding poly- as the prefix
- What is the name of a polymer if propene is used?
addition polymerisation
polypropene
What happens during condensation polymerisation? What is removed?
Condensation polymers are formed when monomer molecules are linked together with the removal of a small molecule, usually water
What is used in condensation polymerisation?
Condensation polymerisation usually involves two different monomers, each one having a functional group on each end
How can condensation polymerisation be reversed?
Hydrolysing (adding water) to the compound in acidic conditions usually reverses the reaction and produces the monomers by rupturing the peptide link
What is used to display the formula of a polymer molecule?
Repeat units are used when displaying the formula
- What is different between the bonds in a monomer and a repeating unit?
(drawing repeating units)
Change the double bond in the monomer to a single bond in the repeat unit
- What needs to be added to each end when drawing a repeating unit?
(drawing repeating units)
Add a bond to each end of the repeat unit
- What must be remembered when drawing bonds on either side of a repeating unit?
(drawing repeating units)
The bonds on either side of the polymer must extend outside the brackets (these are called extension or continuation bonds)
- What symbol must be added outside the repeating unit? What does this show?
(drawing repeating units)
A small subscript n is written on the bottom right-hand side to indicate a large number of repeat units
How could you deduce the polymer from a monomer?
- Identify the repeating unit in the polymer
- Change the single bond in the repeat unit to a double bond in the monomer
- Remove the bond from each end of the repeat unit and the subscript n
What type of polymer is nylon?
A POLYAMIDE - a polymer where the monomer units are joined together by amide (peptide) links
What is nylon made of?
made from dicarboxylic acid monomers and diamines
What is a dicarboxylic acid?
a carboxylic with a -COOH group at either end
What is a diamine?
an amine with an -NH2 group at either end
What groups react together in the formation of nylon?
Each -COOH group reacts with another -NH2 group on another monomer
What is formed during the formation of nylon?
An amide linkage is formed with the subsequent loss of one water molecule per link
What do carbohydrates provide?
Carbohydrates provide energy which is released during cellular respiration
Why are proteins important?
Proteins are the building blocks of cells and are essential for growth and all of the enzyme catalysts in the body are proteins
What type of polymers are proteins?
Proteins are condensation polymers
What monomers are proteins made from? What bonds join them?
formed from amino acid monomers joined together by peptide bonds, similar to the structure in Nylon
How does the structure of a protein differ from nylon?
The units in proteins are different however, consisting of amino acids
What are amino acids?
Amino acids are small molecules containing NH2 and COOH functional groups
how many amino acids do most proteins contain?
Most proteins contain at least 20 different amino acids
- What can proteins be hydrolysed by?
Hydrolysis of proteins
Proteins can be hydrolysed by the addition of water in acidic or alkaline conditions
- What conditions are used to hydrolyse proteins?
Hydrolysis of proteins
Heat and concentrated acid (usually 6 mol/dm3 HCl) are used with a reflux condenser
- Why is a reflux condenser used?
Hydrolysis of proteins
to prevent the acidic vapours from escaping the reaction vessel
- What is added after the reaction is complete?
Hydrolysis of proteins
Aqueous ammonia is added after completion to neutralise the excess acid
- What other substance can be used to hydrolyse proteins at room temperature?
Hydrolysis of proteins
Enzymes can also be used to hydrolyse some proteins at room temperature, mimicking natural bodily processes
What are carbohydrates made of?
Carbohydrates are compounds of carbon, hydrogen and oxygen
What general formula do carbohydrates have?
Cx(H2O)y
What two types of carbohydrates are there?
There are simple carbohydrates and complex carbohydrates
What are simple carbohydrates? Give examples
Simple carbohydrates are called monosaccharides and are sugars such as fructose and glucose
What are complex carbohydrates? Give examples
Complex carbohydrates are called polysaccharides such as starch and cellulose.
What type of polymers are complex carbohydrates?
These are condensation polymers formed from simple sugar monomers
What types of monomers are complex carbohydrates made from, which makes them different from proteins?
Complex carbohydrates, unlike proteins, are usually made up of the same monomers
What is eliminated when simple sugars polymerise?
A H2O molecule is eliminated when simple sugars polymerise
What linkage is formed when simple sugars polymerise?
The linkage formed is an -O- linkage called a glycosidic linkage
What process can complex carbohydrates undergo to produce the monomers they were made from?
The complex carbohydrates also undergo hydrolysis and produce the simple sugar monomers from which they were made
How can complex carbohydrates be hydrolysed?
This can be done by refluxing with more moderately concentrated HCl
- What is produced by fermenting simple sugars?
Fermentation of simple sugars
Simple sugars can be fermented to produce alcohol
- What are simple sugars dissolved in and in what conditions?
Fermentation of simple sugars
They are dissolved in water and yeast is added to be fermented between 15 and 35°C in the absence of oxygen for a few days
- How does temperature affect the rate of reaction during the fermentation of simple sugars?
Fermentation of simple sugars
If the temperature is too low the reaction rate will be too slow and if it is too high the enzymes will become denatured
- What type of enzymes does yeast contain?
Fermentation of simple sugars
Yeast contains zymase enzymes (biological catalysts) that break down starch or sugar to glucose
- In what ways does yeast respire due to a lack of oxygen and what does it produce?
Fermentation of simple sugars
The yeast respires anaerobically using the glucose to form ethanol and carbon dioxide
- What is the chemical equation for the anaerobic respiration of yeast?
Fermentation of simple sugars
C6H12O6 + Enzymes → 2CO2 + 2C2H5OH
- How can chromatography be useful in the hydrolysis of carbohydrates and proteins?
(chromatography and the hydrolysis of carbohydrates and proteins)
The identification of the products of the hydrolysis of carbohydrates and proteins can be done using chromatography
- The products of the hydrolysis of carbohydrates and proteins are colourless. How can chromatography still be used?
(chromatography and the hydrolysis of carbohydrates and proteins)
Both carbohydrate and protein monomers are colourless so locating agents must be used
- What type of chromatography is used and why?
chromatography and the hydrolysis of carbohydrates and proteins
A technique called 2-Dimensional paper chromatography is used as some simple sugars and amino acids have the same Rf value
- how does 2-dimensional paper chromatography work?
chromatography and the hydrolysis of carbohydrates and proteins
In this technique a run is carried out in one direction, then the paper is rotated by 90º and performed again using a different solvent
- Why is 2-dimensional paper chromatography useful?
chromatography and the hydrolysis of carbohydrates and proteins
This further separates sample spots that may not have separated in the first run
- What is done with the final chromatogram?
chromatography and the hydrolysis of carbohydrates and proteins
The resulting chromatogram is dried and sprayed with a locating agent
- How are the products identified?
chromatography and the hydrolysis of carbohydrates and proteins
The Rf value of each solvent used is characteristic for each sugar or amino acid
