A student stirs a spoonful of sugar crystals into a beaker of water. The crystals disappear and a colourless solution forms. Tests on the solution find only water molecules and sugar molecules identical to those in the crystals. Why does this show that the change is physical?
The sugar crystals can no longer be seen in the water
No new substance has been made during the change
The sugar particles have melted, turning into a liquid
The sugar particles have become smaller as they spread out
93 exam-style questions on OCR GCSE Chemistry 1.1 The particle model, covering 1.1.1 The particle model and changes of state and 1.1.2 Limitations of the particle model. Each one has a worked solution and a mark scheme showing where the marks go.