A depot is choosing between two aluminium loading ramps. Both ramps can support the same maximum load.
Design A contains 10 kg of aluminium obtained from ore. Design B contains 13 kg of aluminium recovered from used products.
The table shows the energy used for each kilogram of aluminium in a ramp.
| Stage | Design A (MJ per kg) | Design B (MJ per kg) |
|---|---|---|
| Obtaining aluminium from its ore | 200 | 0 |
| Collecting and sorting used aluminium | 0 | 6 |
| Melting used aluminium | 0 | 10 |
| Forming the ramp | 8 | 8 |
Calculate the percentage reduction in the total energy needed to produce one ramp when the depot chooses design B rather than design A.
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.