An engineer is choosing a material for a bicycle frame. The material must have a tensile strength to density ratio of at least 160 and must not corrode in wet air. The engineer wants the cheapest material that meets both requirements.
| Material | Density (g cm−3\mathrm{g\,cm^{-3}}gcm−3) | Tensile strength (MPa\mathrm{MPa}MPa) | Corrodes in wet air? | Relative cost |
|---|---|---|---|---|
| carbon steel | 7.8 | 1170 | yes | 1 |
| aluminium alloy | 2.7 | 460 | no | 3 |
| titanium alloy | 4.5 | 900 | no | 10 |
| carbon fibre composite | 1.6 | 600 | no | 8 |
Which material should the engineer choose?
carbon steel
aluminium alloy
titanium alloy
carbon fibre composite
36 exam-style questions on Edexcel GCSE Chemistry 10.5 Bulk and surface properties of matter including nanoparticles, covering 10.5.1 Nanoparticles: size, uses and risks and 10.5.2 Comparing and selecting materials. Each one has a worked solution and a mark scheme showing where the marks go.