AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Alkenes are used to produce polymers and as starting materials for the…
Full specification wording
Cracking and alkenes: Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.
Alkenes contain a carbon–carbon double bond, which makes them reactive and valuable in the chemical industry.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 8 of 11
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Alkenes contain a carbon–carbon double bond, which makes them reactive and valuable in the chemical industry. Their main use is to produce polymers by addition polymerisation: many alkene monomers join together to form a long-chain polymer such as poly(ethene) from ethene or poly(propene) from propene. These polymers are used for bags, bottles, pipes and fibres. Alkenes are also starting materials, or feedstocks, for making many other chemicals, including ethanol, ethanoic acid, antifreeze and detergents. The double bond allows addition reactions that convert alkenes into a wide range of products, so cracking is important because it supplies the alkenes needed by industry.
What earns the marks
- Alkenes contain a C=C double bond that makes them reactive.
- Alkenes undergo addition polymerisation to form polymers.
- Ethene forms poly(ethene) and propene forms poly(propene) as examples.
- Polymers made from alkenes are used for packaging, bottles, pipes and fibres.
- Alkenes are feedstocks for making other chemicals such as ethanol and ethanoic acid.
- Cracking supplies alkenes because they are in demand as chemical starting materials.
Common mistakes and how to put them right
Saying alkenes are used to make fuels only.
Put it right: Alkenes are mainly used to make polymers and other chemicals.
Confusing addition polymerisation with condensation polymerisation.
Put it right: Alkene polymerisation is addition, with no small molecule eliminated.
Writing that polymers are made from alkanes.
Put it right: The C=C double bond in alkenes allows addition polymerisation.
Exam tips
- Give a named polymer and its monomer to show the link clearly.
- Use the term feedstock when describing alkenes as starting materials.
- Link the reactivity of the double bond to both polymerisation and other addition reactions.
Try the lesson
The start of the Cracking and alkenes: Alkenes are used to produce polymers and as starting materials for the production of many other chemicals. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of these is an alkene that is used as a starting material to produce many other chemicals?
Listen
Alkenes contain a carbon–carbon double bond, which makes them reactive and valuable in the chemical industry. Their main use is to produce polymers by addition polymerisation: many alkene monomers join together to form a long-chain polymer such as poly(ethene) from ethene or poly(propene) from propene. These polymers are used for bags, bottles, pipes and fibres. Alkenes are also starting materials, or feedstocks, for making many other chemicals, including ethanol, ethanoic acid, antifreeze and detergents. The double bond allows addition reactions that convert alkenes into a wide range of products, so cracking is important because it supplies the alkenes needed by industry. A strong answer earns marks for these points. Alkenes contain a C=C double bond that makes them reactive. Alkenes undergo addition polymerisation to form polymers. Ethene forms poly(ethene) and propene forms poly(propene) as examples. Polymers made from alkenes are used for packaging, bottles, pipes and fibres. A common slip: Saying alkenes are used to make fuels only. Instead, alkenes are mainly used to make polymers and other chemicals. Exam tip: Give a named polymer and its monomer to show the link clearly.
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Key words
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Addition polymerisation
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Industrial feedstocks
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Reactivity of the C=C double bond
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Uses of polymers
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See every definition
- Addition polymerisation
- Many alkene monomers join together to form a long-chain polymer, with no small molecule eliminated.
- Industrial feedstocks
- Alkenes act as starting materials for making many other chemicals, including ethanol and ethanoic acid.
- Reactivity of the C=C double bond
- The carbon–carbon double bond makes alkenes reactive and allows addition reactions that convert them into a wide range of products.
- Uses of polymers
- Polymers made from alkenes are used for bags, bottles, pipes and fibres.
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