One student says that mass is always conserved when a substance changes state. A second student says that the reading on a balance always stays the same when a substance changes state. Which statement is correct?
The first is right, but the second is wrong if vapour can escape
The first is wrong, but the second is right in a sealed container
Both are right because a change of state is a physical change
Both are wrong because some mass is always lost during boiling
40 exam-style questions on AQA GCSE Physics 3.1 Changes of state and the particle model, covering 3.1.1 Density of materials and 3.1.2 Changes of state. Each one has a worked solution and a mark scheme showing where the marks go.