A company makes covers for machines. Each cover has a volume of 2000 cm3\mathrm{cm^{3}}cm3 and must have a strength of at least 100 MPa.
| Material | Density (g/cm3\mathrm{g/cm^{3}}g/cm3) | Strength (MPa) | Cost per kg (£) |
|---|---|---|---|
| Aluminium | 2.7 | 300 | 2.50 |
| Glass-reinforced plastic | 1.9 | 200 | 4.00 |
| Poly(propene) | 0.9 | 35 | 1.20 |
| Steel | 7.8 | 400 | 1.00 |
Which material gives the cheapest cover that is strong enough?
Aluminium
Glass-reinforced plastic
Poly(propene)
Steel
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.