A greenhouse has steel tracks that open roof vents. The tracks are often scratched during use.
A technician attached strips of metal P or metal Q to scratched samples of the steel. The metal strips had the same exposed surface area. Each sample was exposed to air and sprayed with water.
| Metal strip | Initial mass of strip in g | Mass of strip after 12 weeks in g | Appearance of steel after 12 weeks |
|---|---|---|---|
| P | 40.0 | 36.8 | No visible rust |
| Q | 40.0 | 40.0 | Rust visible |
Explain which metal should be attached to the greenhouse tracks. Use the results and explain why strips of the chosen metal will eventually need to be replaced.
118 exam-style questions on AQA GCSE Chemistry 10.3 Using materials, covering 10.3.1 Corrosion and its prevention, 10.3.2 Alloys as useful materials, and 10.3.3 Ceramics, polymers and composites. Each one has a worked solution and a mark scheme showing where the marks go.