A council must choose a material for new park benches. The council will replace each bench at the end of its expected service life.
| Material | Energy needed to manufacture one bench in MJ | Expected service life in years | Material recovered for recycling at the end of its life (%) | Mass of one bench in kg | Source of raw material |
|---|---|---|---|---|---|
| Steel | 2400 | 30 | 88 | 65 | Metal ore |
| Poly(ethene) | 900 | 15 | 35 | 28 | Crude oil |
| Timber | 1400 | 20 | 10 | 45 | Managed plantation in which trees are replaced as fast as they are harvested |
The council wants to provide a bench at one location for 60 years.
Calculate the total energy needed to manufacture the poly(ethene) benches required during the 60 years.
Evaluate the sustainability of using each material for the benches.
You should decide which material the council should use.
87 exam-style questions on AQA GCSE Chemistry 10.1 Using the Earth's resources and obtaining potable water, covering 10.1.1 Using the Earth's resources and sustainable development, 10.1.2 Potable water, 10.1.3 Waste water treatment, and 10.1.4 Alternative methods of extracting metals. Each one has a worked solution and a mark scheme showing where the marks go.