Polymers (OCR A Level Chemistry)

Exam Questions

2 hours27 questions
1a2 marks

This question is about condensation polymers.

State the names of two classes of organic molecules that can take part in condensation polymerisation.

1b1 mark

Draw the structure of the dicarboxylic acid whose formula is C4H6O4. The functional groups should be displayed clearly.

1c1 mark

State the IUPAC name of the dicarboxylic acid in part b)

1d2 marks

Draw one repeat unit of the polymer formed when C4H6O polymerises with diethylamine, H2NCH2CH2NH2.

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2a2 marks

The structure of a synthetic polyester is shown below.

6-6_q2a-ocr-a-as--a-level-easy-sq

Deduce the structures of two monomers used to make this polyester.

2b1 mark

One of the monomers is called benzene-1,4-dicarboxylic acid. State the name of the other one.

2c1 mark

Name the other product of the reaction between the two monomers in b).

2d1 mark

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?

6-6_q2d-ocr-a-as--a-level-easy-sq

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3a1 mark

This question is about hydrolysis of polymers.

What is meant by a hydrolysis reaction?

3b2 marks

Describe the reaction conditions and state what occurs to the polyester during acid hydrolysis.

3c2 marks

Outline the difference in the product(s) between acid and base hydrolysis of a polyester.

3d4 marks

Draw structures for the products of acid and base hydrolysis of the following polymer:


6-6_q3d-ocr-a-as--a-level-easy-sq

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4a1 mark

This question is about repeat units in polymers

Draw the repeat unit of the polymer made from ClCH=CHCH3.

4b2 marks

2-aminoethanoic acid, H2NCH2COOH, can undergo polymerisation. 

State the type of polymerisation taking place and draw the repeat unit.

4c1 mark

A section of a protein polymer is shown below. How many monomer units are shown in the diagram?

6-6_q4c-ocr-a-as--a-level-easy-sq
4d1 mark

Draw a displayed structure for one of the monomer units in c)

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1a3 marks

Poly(phenylethene) is widely used as a polymer for many purposes such as packaging. The structure of poly(phenylethene) is shown below. 

1-8

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. 

1b5 marks

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. 

2-6

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.

1c6 marks

Explain why poly(phenylethene) drawn in part (a) is far less reactive than Terylene described in part (b).

1d1 mark

Identify a solution that would break down Terylene but not break down poly(phenylethene).

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2a3 marks

The structure of Kevlar is shown below. State the type of polymerisation and draw the two monomers used to make Kevlar. 

3-6

2b4 marks

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. 

Kevlar strand

 

2c6 marks

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. 

2d2 marks

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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3a1 mark

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.  

5-3

3b1 mark

A dipeptide made from the amino acids cysteine and tryptophan is shown below. Cysteine contains a sulphur molecule. 

7

Draw the structure of the amino acid tryptophan.

3c3 marks

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.

8

In terms of intermolecular forces between the polymer chains, explain why polyalkenes are not suitable to be used as fibres for weaving.

3d2 marks

Explain why the molecule NH2CH2CH2COCl can form a condensation polymer with itself. 

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4a3 marks

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.

aqa-chemistry-trial-june

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. 

 

4b5 marks

Nylon can be used to make clothing. Suggest why nylon should be protected from spillages of strong acids and alkalis.

4c2 marks

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.

10

4d3 marks

Draw the two monomers that are used to manufacture Nomex and give the formula of any by-products produced. 

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1a3 marks

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]
1b1 mark

Polylactic acid contains methyl groups. Use this information to draw a displayed formula showing three repeat units of poly(lactic acid).

1c2 marks

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.

1d2 marks

Name and draw another monomer that could make poly(lactic acid).

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2a1 mark

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:

serine

Explain why serine is described as an α-amino acid

2b2 marks

Serine reacts with dilute sodium hydroxide. Write an equation for the reaction and draw the structure of the product.

2c2 marks

Serine exists as two optical isomers.

Draw the two optical isomers of serine.

2d4 marks

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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3a1 mark

Nylon-6,6 and nylon-6,12 are two condensation polymers made from hexane-1,6-diamine and another monomer.

6-6_q3d-12-ocr-a-as--a-level-hard-sq

Draw the skeletal formula of the other monomer that could be used to make nylon-6,12

3b2 marks

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.

3c2 marks

Another type of nylon is nylon-6. Suggest how it is possible to make nylon-6 and draw the repeat unit.

3d2 marks

Sections of the polymer chain for nylon-6,6 and nylon-6,12 are shown below.

nylon-66
nylon-6,6
nylon-612
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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4a2 marks
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.

4b3 marks

Draw the structure of the Nomex ® polymer.

4c2 marks

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 ®. 

4d2 marks

State whether Kevlar ® or Nomex ® will have the higher melting point. 

Justify your answer.

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