The table shows the melting points and boiling points of four substances, P, Q, R and S.
| Substance | Melting point (∘C^\circ\mathrm{C}∘C) | Boiling point (∘C^\circ\mathrm{C}∘C) |
|---|---|---|
| P | −182 | −162 |
| Q | 17 | 78 |
| R | 98 | 883 |
| S | −95 | 56 |
Which substance is a solid at 25 ∘C^\circ\mathrm{C}∘C?
Which substance changes state twice when it is heated from 0 ∘C^\circ\mathrm{C}∘C to 100 ∘C^\circ\mathrm{C}∘C?
Name both changes of state.
Explain why substance R has a much higher boiling point than substance P.
Use ideas about forces and energy.
Substance Q is cooled from 150 ∘C^\circ\mathrm{C}∘C to 60 ∘C^\circ\mathrm{C}∘C.
Describe how the arrangement, movement and spacing of the particles of Q change.
48 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.