Exam code: H432
This question is about condensation polymers.
State the names of two classes of organic molecules that can take part in condensation polymerisation.
Draw the structure of the dicarboxylic acid whose formula is C4H6O4. The functional groups should be displayed clearly.
State the IUPAC name of the dicarboxylic acid in part b)
Draw one repeat unit of the polymer formed when C4H6O4 polymerises with diethylamine, H2NCH2CH2NH2.
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The structure of a synthetic polyester is shown below.
Deduce the structures of two monomers used to make this polyester.
One of the monomers is called benzene-1,4-dicarboxylic acid. State the name of the other one.
Name the other product of the reaction between the two monomers in b).
Benzene-1,4-dicarboxylic acid will also react to form a polyamide.
Which of the three molecules could react with benzene-1,4-dicarboxylic acid to form a polyamide?
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This question is about hydrolysis of polymers.
What is meant by a hydrolysis reaction?
Describe the reaction conditions and state what occurs to the polyester during acid hydrolysis.
Outline the difference in the product(s) between acid and base hydrolysis of a polyester.
Draw structures for the products of acid and base hydrolysis of the following polymer:
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This question is about repeat units in polymers
Draw the repeat unit of the polymer made from ClCH=CHCH3.
2-aminoethanoic acid, H2NCH2COOH, can undergo polymerisation.
State the type of polymerisation taking place and draw the repeat unit.
A section of a protein polymer is shown below. How many monomer units are shown in the diagram?
Draw a displayed structure for one of the monomer units in c)
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Poly(phenylethene) is widely used as a polymer for many purposes such as packaging. The structure of poly(phenylethene) is shown below.
i) State the type of polymerisation and the draw the monomer used to make poly(phenylethene).
ii) Suggest why the monomer is liquid at room temperature but poly(phenylethene) is in the solid state at room temperature.
Terylene was one of the first man made polymers produced to be used as fibres for clothing. The structures of the two monomers used to make Terylene are shown below.
i) Give the IUPAC names for Compound A and Compound B.
ii) Draw the structure of the repeating unit produced from these two monomers.
iii) Give the name of this type of polymerisation.
iv) Give the name of the linkage once the polymer has been formed.
Explain why poly(phenylethene) drawn in part (a) is far less reactive than Terylene described in part (b).
Identify a solution that would break down Terylene but not break down poly(phenylethene).
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The structure of Kevlar is shown below. State the type of polymerisation and draw the two monomers used to make Kevlar.
Draw a second strand of Kevlar underneath to show how the strands are attached to one another.
Use your diagram to explain why Kevlar can be used for making items that require high strength.
High density poly(ethene), HDPE, is an example of a polyalkene and is used to make items such as plastic pipes and washing up bowls.
State the difference in biodegradability between Kevlar and high density poly(ethene), HDPE. Use your knowledge of structure and bonding to explain this difference.
Draw the salt formed when Kevlar reacts with hot, concentrated sodium hydroxide and give the name of this type of reaction.
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Valylalanine shown below, is an example of a dipeptide composed of two amino acids, valine and alanine.
When this compound is placed in acidic conditions, two species are formed.
Draw one of these two species.
A dipeptide made from the amino acids cysteine and tryptophan is shown below. Cysteine contains a sulphur molecule.
Draw the structure of the amino acid tryptophan.
Amino acids such as serine shown below will form polyamide links. Polyamides will contain the same type of links and these polymers can be used to form fibres suitable for weaving. Polymers formed from alkenes by additional polymerisation are usually took weak for this purpose.
In terms of intermolecular forces between the polymer chains, explain why polyalkenes are not suitable to be used as fibres for weaving.
Explain why the molecule NH2CH2CH2COCl can form a condensation polymer with itself.
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Nylon is an example of a synthetic polyamide and contains the same links as polypeptides. Nylon is the general name for a family of polyamides. A section of a nylon polymer is shown below.
i) Draw the structures of two monomers that could be used to make this nylon.
ii) State the type of polymerisation involved in the formation of this nylon.
Nylon can be used to make clothing. Suggest why nylon should be protected from spillages of strong acids and alkalis.
Nomex, drawn below has a higher melting point than nylon and is used to make the flame resistant body suits worn by racing drivers.
Suggest a reason why the melting point of Nomex is higher than that of nylon.
Draw the two monomers that are used to manufacture Nomex and give the formula of any by-products produced.
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Polymers made from naturally occurring substances present exciting new materials that do not rely on fossil fuels.
This question is about poly(lactic acid) a thermoplastic polyester made from lactic acid, C3H6O3. It is a renewable material used widely in 3D printers.
i) Draw a diagram for a possible structure for lactic acid and explain why it can be polymerised.
[2]
ii) Give the systematic IUPAC name for your structure.
[1]
Polylactic acid contains methyl groups. Use this information to draw a displayed formula showing three repeat units of poly(lactic acid).
Several distinct forms of poly(lactic acid) exist, due to the chiral nature of lactic acid.
Explain what this means and state what happens to the chirality when lactic acid is polymerised.
Name and draw another monomer that could make poly(lactic acid).
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Serine is an α-amino acid that is synthesised in the human body and can also be used in the biosynthesis of proteins.
The structure of serine is shown below:
Explain why serine is described as an α-amino acid
Serine reacts with dilute sodium hydroxide. Write an equation for the reaction and draw the structure of the product.
Serine exists as two optical isomers.
Draw the two optical isomers of serine.
Serine is able to undergo two different condensation polymerisation reactions.
Draw two repeat units formed from serine for each polymerisation reaction.
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Nylon-6,6 and nylon-6,12 are two condensation polymers made from hexane-1,6-diamine and another monomer.
Draw the skeletal formula of the other monomer that could be used to make nylon-6,12
Nylon-6,6 and nylon-6,12 have slightly different properties.
Suggest why nylon-6,12 has a lower melting point and lower strength than nylon-6,6.
Another type of nylon is nylon-6. Suggest how it is possible to make nylon-6 and draw the repeat unit.
Sections of the polymer chain for nylon-6,6 and nylon-6,12 are shown below.
nylon-6,6
nylon-6,12
Complete the table of information about the repeat units
Polymer | nylon-6,6 | nylon-6,12 | ||
Group | -CH2- | -CONH - | -CH2- | -CONH- |
Number of groups in the repeat units |
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One family of condensation polymers are the aramids, so called because of the arene rings that are linked together with amide bonds. Kevlar ® and Nomex ® are two common examples of aramids.
Kevlar ® has a variety of uses, including bulletproof vests and puncture resistant tyres, due to its strength and being lightweight. Nomex ® is most commonly used as a lining of the overalls worn by racing drivers and their pit crews as well as in the personal protective equipment of firefighters due to its flame resistant properties.
Nomex ® is made from 1,3-diaminobenzene and 1,3-benzenedicarboxylic acid.
Draw the skeletal structures of these monomers.
Draw the structure of the Nomex ® polymer.
Kevlar ® is made from 1,4-diaminobenzene and 1,4-benzenedicarboxylic acid.
Draw two repeat units of the polymer to show the strongest intermolecular force in Kevlar ®.
State whether Kevlar ® or Nomex ® will have the higher melting point.
Justify your answer.
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