Four identical metal test plates each had an initial mass of 40.00 g and a thickness of 2.00 mm. The plates were exposed to damp air containing exhaust gases for different lengths of time.
After exposure, surface material was collected for analysis. Each plate was then cleaned, dried and measured.
| Time exposed in days | Mass of plate in g | Minimum thickness of plate in mm |
|---|---|---|
| 0 | 40.00 | 2.00 |
| 30 | 39.92 | 1.99 |
| 60 | 39.78 | 1.97 |
| 90 | 39.57 | 1.94 |
Analysis showed that the surface material was a compound of the metal and oxygen.
Describe how the results show that corrosion occurred.
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.