Identical uncoated steel fasteners are placed in sealed packages. Before package Q is sealed, oxygen is removed from both the atmosphere and the water. The water in package Q contains no dissolved oxygen.
The table shows the contents of each package and the result after 21 days.
| Package | Atmosphere | Other material in the package | Result after 21 days |
|---|---|---|---|
| P | Air | Drying agent | No rust |
| Q | Oxygen-free gas | Water | No rust |
| R | Air | Water | Rust formed |
Explain the results for all three packages.
A small hole allows air to enter package Q. The water remains in the package.
Predict what will happen to the steel fastener. Explain your answer.
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.