A student sets up five test tubes, each containing an iron nail, and leaves them for one week.
| Tube | Conditions | Rust after one week |
|---|---|---|
| 1 | tap water, open to the air | some |
| 2 | boiled water with a layer of oil on top | none |
| 3 | dry air with anhydrous calcium chloride | none |
| 4 | salt water, open to the air | a lot |
| 5 | painted nail in tap water, open to the air | none |
Which two tubes should be compared to show that oxygen is needed for rusting?
Tubes 1 and 3
Tubes 1 and 4
Tubes 2 and 3
Tubes 1 and 2
42 exam-style questions on Edexcel GCSE Chemistry 6.1 Transition metals, alloys and corrosion, covering 6.1.1 Properties of transition metals, 6.1.2 Corrosion and its prevention, and 6.1.3 Alloys and the uses of metals. Each one has a worked solution and a mark scheme showing where the marks go.