A food distribution centre is considering separate recycling schemes for aluminium foil and glass packaging.
The table gives data for one month.
| Material | Mass collected per month (kg) | Suitable for recycling (%) | Energy to make 1 tonne from raw materials (GJ) | Energy to make 1 tonne from recycled material (GJ) | Energy used for collection and sorting per month (GJ) |
|---|---|---|---|---|---|
| Aluminium | 750 | 80 | 180 | 9 | 3.6 |
| Glass | 12 000 | 95 | 14 | 9 | 8.0 |
Calculate the net energy saving per month for each recycling scheme.
Use your answers to state which scheme should be introduced if the centre's only aim is to save energy.
Explain one reason why the scheme selected in part (a) could still be uneconomic, even though it saves more energy.
136 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.