Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Synthetic Polymers
107 practice questions
Topics covered
Practice questions
11–18 of 18 · Hard
Question 11
5 marks · Hard
Answer and see the solution →The polymerisation of propane-1,3-diol and benzene-1,4-dicarboxylic acid forms a polyester. Propane-1,3-diol has the formula and benzene-1,4-dicarboxylic acid has the formula .
(a)[2 marks]Draw the structural formula of both monomers.
(b)[1 mark]Explain why water is eliminated when the two monomers react to form the polyester.
(c)[1 mark]State one everyday use of polyesters produced in this way.
(d)[1 mark]Name the type of polymerisation that occurs and give one reason for this classification.
Question 12
2 marks · Hard
Answer and see the solution →Describe the main structural features that all polyesters have in common. Suggest why these features are important for the properties and uses of polyesters.
Question 13
2 marks · Hard
Answer and see the solution →Describe how the biodegradable polyester polylactic acid (PLA) can be made from its monomer, lactic acid. In your answer, state the name of both the process and the type of chemical reaction involved.
Question 14
5 marks · Hard
Answer and see the solution →Polyesters, such as polylactic acid (PLA), often biodegrade more rapidly than addition polymers like poly(ethene).
Answer the following questions about their biodegradability.
(a)[1 mark]Explain what is meant by 'biodegradable polyester'.
(b)[1 mark]State what is meant by an 'ester linkage' in the context of polyester structure.
(c)[3 marks]Compare the biodegradability of polyesters (such as PLA) and addition polymers (such as poly(ethene)).
Explain why polyesters with ester linkages are more biodegradable, referring to the chemical structure and environmental breakdown processes.
Question 15
2 marks · Hard
Answer and see the solution →Lactic acid is the monomer for polylactic acid (PLA). What is the displayed (structural) formula for the part of a PLA chain that is actually repeated in the polymer? Describe or draw the repeat unit of PLA, indicating the ester linkage.
Question 16
8 marks · Hard
Answer and see the solution →Polymers can be made using different methods, giving materials with different environmental impacts. Use your knowledge of both addition polymerisation and biodegradable polyesters to answer the following.
(a)[2 marks]Draw the displayed formula for the repeat unit of poly(propene), an addition polymer.
(b)Lactic acid (CH3CH(OH)COOH) can be used to make a biodegradable polyester called PLA (polylactic acid).
(i)[2 marks]Describe how lactic acid monomers join to form PLA. Include the type of reaction and the functional groups involved.
(ii)[2 marks]Draw the displayed formula for the repeat unit of polylactic acid (PLA).
(c)[2 marks]State one advantage of using biodegradable polyesters like PLA instead of addition polymers such as poly(propene) for disposable items.
Question 17
7 marks · Hard
Answer and see the solution →Many artificial polymers have useful properties but create environmental concerns. Answer the following questions about their preparation and degradation.
(a)[2 marks]Describe how addition polymers such as poly(chloroethene) are prepared from their monomers, including the conditions needed.
(b)[2 marks]State and explain one main reason why addition polymers like poly(chloroethene) are not easily biodegradable.
(c)[3 marks]Explain why polyesters such as polylactic acid (PLA) are considered more biodegradable than addition polymers.
Question 18
8 marks · Hard
Answer and see the solution →This question is about the structures of polymers made by different processes.
(a)[2 marks]Draw the displayed formula for the repeat unit of poly(ethene), an addition polymer.
(b)Lactic acid, CH3CH(OH)COOH, can polymerise to form a biodegradable polyester (polylactic acid, PLA).
(i)[2 marks]Draw the structure of a lactic acid monomer, showing all atoms and bonds.
(ii)[2 marks]Draw the displayed formula for the repeat unit of polylactic acid (PLA), as formed from lactic acid.
(c)[2 marks]Explain why PLA is biodegradable, but poly(ethene) is not.