Chemistry (9-1) - 0971 CIE

Polymers

Overview

Plastics are everywhere, from drink bottles to clothing, and almost all of them are polymers: giant molecules built by joining thousands of small units together. Understanding how these long chains form, from simple alkenes, explains both their usefulness and their environmental challenges.

In this lesson you will learn what a polymer and a monomer are, how many alkene monomers join by addition polymerisation to make a polymer such as poly(ethene), and why the strength of these molecules also makes their waste so hard to dispose of.

Objectives

Define polymers as large molecules built up from many smaller molecules called monomers.
Describe the formation of poly(ethene) as an example of addition polymerisation using ethene monomers.
State that plastics are made from polymers.
Describe how the properties of plastics have implications for their disposal.
Describe the environmental challenges caused by plastics, limited to: (a) disposal in landfill sites (b) accumulation in oceans (c) formation of toxic gases from burning.
[Supplement] Identify the repeat units and / or linkages in addition polymers and in condensation polymers.
[Supplement] Deduce the structure or repeat unit of an addition polymer from a given alkene and vice versa.
[Supplement] Deduce the structure or repeat unit of a condensation polymer from given monomers and vice versa, limited to: (a) polyamides from a dicarboxylic acid and a diamine (b) polyesters from a dicarboxylic acid and a diol.
[Supplement] Describe the differences between addition and condensation polymerisation.
[Supplement] Describe and draw the structure of: (a) nylon, a polyamide O O O O C C N N C C N N H H H H (b) PET, a polyester O O O O C C O O C C O O The full name for PET, polyethylene terephthalate, is not required.
[Supplement] State that PET can be converted back into monomers and re-polymerised.
[Supplement] Describe and draw the structure of proteins as: H O H O N C N C N C H O.

Lesson Note

Polymers are among the most useful materials ever made, cheap, strong and easily shaped. The same properties that make them useful also make their waste a problem, because they do not break down easily. Understanding how polymers form is the first step to using them wisely.

Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams

AI-powered learning assistant

Study offline, anytime, anywhere

Download Mobile App Download Desktop App

Available on Android, Windows, macOS, and Linux

Lesson Evaluation

Congratulations on completing the lesson on Polymers. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

A polymer is a large molecule made by joining many: A. Atoms of one element B. Monomers C. Salts D. Acids Answer: B
The monomer used to make poly(ethene) is: A. Ethane B. Ethene C. Ethanol D. Ethanoic acid Answer: B
In addition polymerisation, the monomers join because their: A. -OH groups react B. Double bonds open C. Single bonds break D. Acids neutralise Answer: B
In addition polymerisation, the number of products formed is: A. Only the polymer B. The polymer and water C. The polymer and carbon dioxide D. Two polymers Answer: A
A major environmental problem with addition polymers is that they: A. Dissolve in water B. Do not break down easily C. Evaporate quickly D. React with air Answer: B