A café wants to choose a type of cup for hot drinks.
Cup A is a single-use paper cup with a thin plastic lining. It is used once and then thrown away.
Cup B is a reusable stainless steel cup. It is washed after every use. One cup B lasts for 500 uses.
The table shows some life cycle assessment (LCA) data for one cup of each type.
| Stage of the life cycle | Energy used for one cup A (MJ) | Energy used for one cup B (MJ) |
|---|---|---|
| getting the raw materials | 0.40 | 30.0 |
| manufacturing the cup | 0.20 | 15.0 |
| washing (each use) | 0 | 0.12 |
| disposal | 0.05 | 0.50 |
An LCA also looks at things other than energy.
Give one other thing that should be included in an LCA of the cups.
Calculate the total energy used for one cup A.
Calculate the energy used per use for cup B over its whole life of 500 uses.
Give your answer to 2 significant figures.
Energy used per use = ...... MJ
The café owner says:
"Cup A is better for the environment, because one cup A uses much less energy than one cup B."
Evaluate the café owner's statement. Use your answers to (b).
Cup A has a plastic lining stuck to the paper.
Suggest why cup A is difficult to recycle.
At the end of its life, cup B can be melted down. The steel can be used to make different products, such as car parts.
Explain why recycling the steel in this way is worthwhile.
61 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.