Iron wool reacts to form iron oxide when it is heated. A student heats iron wool once in an open container and once in a sealed container that contains air. The results are shown below.
| Trial | Container | Mass of container and contents before heating (g) | Mass of container and contents after heating (g) |
|---|---|---|---|
| A | Open | 52.36 | 52.60 |
| B | Sealed | 52.36 | 52.36 |
Calculate the mass increase in trial A.
Explain why the balance readings changed differently in the two trials.
95 exam-style questions on AQA GCSE Chemistry 3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, covering 3.1.1 Conservation of mass and balanced chemical equations, 3.1.2 Relative formula mass, 3.1.3 Mass changes when a reactant or product is a gas, and 3.1.4 Chemical measurements. Each one has a worked solution and a mark scheme showing where the marks go.