A variable-volume apparatus has a mass of 250.0 g and contains an 18.0 g sample of a pure substance. The apparatus is sealed while measurements are taken in each state.
| State | Volume occupied by the sample in cm3\mathrm{cm^3}cm3 | Balance reading in g\mathrm{g}g |
|---|---|---|
| solid | 15 | 268.0 |
| liquid | 16 | 268.0 |
| gas | 15 000 | 268.0 |
After the final measurement, a tap is opened and the substance is allowed to escape into the room as a gas.
Explain how the particle model accounts for the volumes and differences in density indicated by the results, and for the balance readings before and after the tap is opened.
87 exam-style questions on Edexcel GCSE Physics 14.1 Density and states of matter, covering 14.1.1 Kinetic theory and states of matter, 14.1.2 Density, and 14.1.3 Density and changes of state. Each one has a worked solution and a mark scheme showing where the marks go.