AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
The amount of separation required for recycling depends on the material…
Full specification wording
Ways of reducing the use of resources: The amount of separation required for recycling depends on the material and the properties required of the final product.
Recycling a material rarely means it can be used again exactly as it was collected.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 9 of 11
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Recycling a material rarely means it can be used again exactly as it was collected. The material must be separated from other materials, and how much separation is needed depends on two linked ideas: what the material is, and what the final product must do. For example, scrap steel from a car contains copper wire, plastic and paint. If the recycled steel is to be made into new car body panels, the copper must be removed almost completely, because even a small amount of copper makes steel crack when it is rolled and shaped. If the recycled steel is to be made into a less demanding product such as reinforcing bar for concrete, less separation is acceptable. So the same material can need different amounts of separation depending on the properties required of the final product.
What earns the marks
- Separation is needed because collected waste is usually a mixture of different materials, and these must be sorted before the material can be reused.
- The identity of the material matters: metals, glass, paper and plastics each need different separation methods, such as magnetic separation for steel or density separation for plastics.
- The properties required of the final product set how pure the recycled material must be, for example strength, flexibility, appearance or electrical conductivity.
- A high-purity product usually needs more separation stages, which uses more energy and costs more, so there is a trade-off between purity and cost.
- Impurities can change properties: copper in steel makes it crack during rolling, and mixed polymers can make a recycled plastic weak or cloudy.
- A suitable answer links a named material, a named final product and the property that decides how much separation is needed.
Common mistakes and how to put them right
Thinking all recycling needs the same amount of separation.
Put it right: The required separation depends on the material and on the properties needed in the final product.
Assuming recycled material must always be pure.
Put it right: Some products tolerate impurities, so less separation may be enough.
Confusing separation with extraction.
Put it right: Separation sorts a material from a mixture, while extraction obtains a metal from its compound in an ore.
Exam tips
- Name the material and the final product in your answer, then state the property that the product needs.
- Use the phrase 'the amount of separation depends on' and then give both factors from the statement.
- If data about energy or cost is given, compare the separation needed for two different final products rather than describing recycling in general.
Try the lesson
The start of the Ways of reducing the use of resources: The amount of separation required for recycling depends on the material and the properties required of the final product. lesson, made from checked teaching notes for this specification point.
Have a go first
When recycling waste, different mixtures require different amounts of separation. Which two factors determine the amount of separation required?
Listen
Recycling a material rarely means it can be used again exactly as it was collected. The material must be separated from other materials, and how much separation is needed depends on two linked ideas: what the material is, and what the final product must do. For example, scrap steel from a car contains copper wire, plastic and paint. If the recycled steel is to be made into new car body panels, the copper must be removed almost completely, because even a small amount of copper makes steel crack when it is rolled and shaped. If the recycled steel is to be made into a less demanding product such as reinforcing bar for concrete, less separation is acceptable. So the same material can need different amounts of separation depending on the properties required of the final product. A strong answer earns marks for these points. Separation is needed because collected waste is usually a mixture of different materials, and these must be sorted before the material can be reused. The identity of the material matters: metals, glass, paper and plastics each need different separation methods, such as magnetic separation for steel or density separation for plastics. The properties required of the final product set how pure the recycled material must be, for example strength, flexibility, appearance or electrical conductivity. A high-purity product usually needs more separation stages, which uses more energy and costs more, so there is a trade-off between purity and cost. A common slip: Thinking all recycling needs the same amount of separation. Instead, the required separation depends on the material and on the properties needed in the final product. Exam tip: Name the material and the final product in your answer, then state the property that the product needs.
Key words
Say what each word means before you turn the card.
Separation
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Properties required of the final product
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Impurities
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Trade-off between purity and cost
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See every definition
- Separation
- The process of sorting a material from a mixture of different materials before it can be reused.
- Properties required of the final product
- The qualities the final product must have, such as strength, flexibility, appearance or electrical conductivity, which set how pure the recycled material must be.
- Impurities
- Unwanted substances in a material that can change its properties, such as copper in steel making it crack during rolling.
- Trade-off between purity and cost
- A high-purity product usually needs more separation stages, which uses more energy and costs more.
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