Polymerisation (CIE AS Chemistry)

Exam Questions

2 hours31 questions
1a1 mark

This question is about different polymers.

Polymer X can be formed from an alkene. The structure of polymer X is shown in Fig. 1.1.

3-8-1a-e-polypropene
Fig. 1.1

State the type of polymerisation involved in the formation of polymer X.

1b2 marks
i)
Draw the monomer used to form polymer X.

[1]
ii)
Name polymer X.

[1]
1c3 marks

Suggest three reasons why the disposal of polymer X would prove to be a challenge.

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2a6 marks

Butene, C4H8, can exist as three isomers.

Isomer A is a position isomer of isomers B and C and does not show geometric isomerism.

Isomers B and C are geometric isomers of each other.

Isomer B is the cis isomer.

Isomer C  is the trans isomer.

 

i)
Draw the displayed formulae of the three isomers, A, B and C, of butene, C4H8
[3]

 

ii)
Name all three isomers, A, B and C, of butene, C4H8
[3]

2b1 mark

Draw the displayed formula of the addition polymer formed by isomer A.

2c1 mark

A student was asked to draw the displayed formula of the addition polymer of isomers B and C. They suggested that there were two structures as shown in Fig. 2.1.

isomers-b-and-c

Fig. 2.1

State why the student’s two suggested structures are the same addition polymer.

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3a1 mark

A molecule of chloroethene is shown in Fig. 3.1.

chloroethene

Fig. 3.1

Chlorothene can be polymerised to form poly(chloroethene).

State the alternative name for poly(chloroethene).

3b1 mark

Draw a diagram of the structure of poly(chloroethene) including three repeat units.

3c1 mark

State a problem caused by the combustion of poly(chloroethene) as a method of disposal and suggest how the effects of this problem can be reduced.

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1a2 marks

Addition polymers are made by the polymerisation of alkenes.

Explain what is meant by the term addition polymerisation.

1b2 marks

Trans-hept-2-ene can be made into an addition polymer.

i)
Give the displayed formula of trans-hept-2-ene.

[1]

ii)
Draw the structure of poly(hept-2-ene) showing two repeat units.

[1]

1c2 marks

Suggest why the polymer made from trans-hept-2-ene is not called poly(trans-hept-2-ene).

1d3 marks

Trans-hept-2-ene is a liquid at room temperature and pressure but poly(hept-2-ene) is a solid.

Explain why there is a difference in the states of trans-hept-2-ene and poly(hept-2-ene).

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2a1 mark

Polyvinyl chloride (PVC) is a polymer which is rigid enough for use as a drainpipe and flexible enough for plastic aprons.

State the IUPAC name of PVC.

2b4 marks

Fig 2.1 below shows a section of the PVC polymer.

Fig 2.1

3-8-2b-m-pvc-chain-a

i)
Draw the repeating unit of PVC.

[1]

ii)
Draw the structure and state the name of the monomer of the PVC polymer.

[2]

iii)
Write the equation to represent the formation of PVC from its monomer.

[1]

2c6 marks

The polymer poly(propene) is formed from the monomer propene.

i)
Draw the repeating unit of this polymer.

[1]

ii)
The properties of two different polymers, poly(methylpropene) and poly(ethene) are compared to each other. Complete Table 2.1 by placing an X in the correct box. You may place more than one X for each physical property. 

[3]

Table 2.1

Physical property Poly(methylpropene) Poly(ethene)
Insoluble in water    
Unreactive    
High density    



iii)
Explain why the melting point of poly(methylpropene) is much higher than that of methylpropene. 

[2]

2d3 marks

Polymers are unreactive compounds due to their long non-polar chain of saturated carbon-carbon and carbon-hydrogen bonds. Though this means that they are safe to use due it also means that they are non-biodegradable as they are not attacked by biological agents such as enzymes.  

Table 2.2 shows three different ways in which polymers can be disposed of.

Table 2.2

Method of disposal Disadvantage
Recycling  
Incineration  
Landfill  

State the disadvantage of each method of disposal to complete Table 2.2.

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3a1 mark

This question is about different polymers and their uses.

Poly(tetrafluoroethene), also known as PTFE, is an addition polymer used as a non-stick coating in pans as it is very unreactive.


Draw the displayed formula of the monomer used to form PTFE.

3b1 mark

Draw two repeating units of poly(tetrafluorethene).

3c5 marks

The table shows the melting points of two polymers.

Polymer Melting point / °C
Poly(ethene) 137
Poly(chloroethene) (PVC) 212

Explain the differences in melting point of these two polymers in terms of the intermolecular forces between the chains.

3d2 marks

Poly(ethene) bags pollute the environment for a long time because they are non-biodegradable.

Describe two pollution problems that are caused by non-biodegradable polymers.

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4a2 marks

The structures of two different polymers, poly(ethene) and poly(propene) are shown in Fig. 4.1.

SCrZpsHa_3-8-4a-m-polyethene-and-polypropene

Fig. 4.1

Suggest two reasons why these polymers are unreactive.

4b2 marks

State one advantage and one disadvantage of the unreactivity of addition polymers.

4c1 mark

Another example of a polymer is polystyrene which is often used as packing material and electrical insulation.

Fig. 4.2 shows three repeating units of the polymer.

3-8-4c-m-polystyrene-a

Fig. 4.2

 

Draw the structure of monomer X which is used to form the polymer shown in Fig. 4.2.

4d2 marks

Two different monomers can also join together to form an addition polymer.

Monomer X can react with monomer Y to form a polymer. Two repeating units of this polymer are shown in Fig 4.3.

3-8-4d-m-polymer-from-monomers-x-and-y-a

Fig. 4.3

 

i)
Draw the structures of monomer Y which reacts with monomer X to form the polymer shown in Fig. 4.3.

[1]

ii)
State the IUPAC name of monomer Y.

[1]

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5a2 marks

Poly(but-1-ene) is insoluble in water so is used in applications such as making water pipes

Write an equation to show how poly(but-1-ene) is formed from the monomer but-1-ene.

5b4 marks

Not all polymers are insoluble in water. One example is poly(vinylalcohol) known as PVA. PVA is used in applications such as in the casing of detergent-filled capsules.

A section of the polymer chain of PVA is shown in Fig. 5.1.

3-8-5b-m-pva-a

Fig. 5.1

i)
Draw the structure and give the IUPAC name of the monomer of PVA.

[2]

ii)
Suggest why PVA is soluble, but poly(but-1-ene) is not.

[2]

5c2 marks

Combustion can be used to dispose of poly(alkenes), such as poly(but-1-ene).

Give one advantage and one disadvantage to the environment of disposing of polymers by combustion.

5d1 mark

Poly(chloroethene), PVC, can also be disposed of via combustion but it produces toxic waste gases including hydrogen chloride.

Suggest a reagent that can be used to remove this toxic gas from the waste gases.

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1a1 mark

Poly(methyl methacrylate) is used as a glass substitute in Perspex. 

A section of the polymer chain is shown in Fig. 1.1. 

4-3_q3a-ocr-a-as--a-level-hard-sq

Fig. 1.1

Draw the skeletal formula of the monomer. 

1b2 marks

Explain why poly(methylmethacrylate) is fairly unreactive. 

1c3 marks

Bioplastics, such as biodegradable plastics offer a sustainable alternative to oil-based products.

Where the use of plant-based polymers is not possible, photodegradable polymers are being developed. 

i)
Explain how photodegradable polymers are broken down. 
[1]

ii)
Suggest two disadvantages of using photodegradable polymers.

[2]

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2a2 marks

Explain how p-orbitals are involved in the formation of the C=C bond in chloroalkenes.

You should include a sketch in your answer. 

2b5 marks

Compound Y has six possible structural isomers of C3H3Cl3

Two of these isomers are shown in Fig. 2.1.

4-3_q5c-ocr-a-as--a-level-hard-sq

Fig. 2.1

i)
State the IUPAC name of isomer 1.

[1]

ii)
Draw three other structural isomers of C3H3Cl3 that are chloroalkenes. 

[3]

iii)
Show two repeat units for the polymer formed by isomer 2

[1]

2c4 marks

Polymers can be disposed of by incineration. 

i)
Write a balanced symbol equation for the incineration of poly(chloroethene). 
Carbon dioxide, water and HCl are formed.

[1]

ii)
Describe the environmental impact of this reaction and explain how it could be reduced. 

[3]

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3a3 marks

But-2-ene, CH3CH=CHCH3, is an important compound which is obtained from the cracking of hydrocarbons present in crude oil.

Some reactions of but-2-ene are shown in Fig. 3.1.

3-8-3a-h-cie-ial-3-8h-q3a

Fig. 3.1

Give the structural formulae of the organic compounds A to C.

3b1 mark

But-2-ene can be polymerised to give poly(butene). Draw the structural formula of a portion of the polymer chain in poly(butene) showing two repeat units.

3c3 marks

Explain why there is an increasing demand for polymers to be recycled rather than incinerated.

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