Two simple molecular substances, X and Y, are being considered for a process at atmospheric pressure. The substance must be a liquid at −10 ∘C-10\, ^\circ\mathrm{C}−10∘C and a gas at 35 ∘C35\, ^\circ\mathrm{C}35∘C.
| Substance | Melting point / ∘C^\circ\mathrm{C}∘C | Boiling point / ∘C^\circ\mathrm{C}∘C |
|---|---|---|
| X | -45 | 20 |
| Y | -30 | 65 |
State which substance is suitable for this process.
Explain why substance X has a lower boiling point than substance Y.
When substance X changes from a liquid to a gas, explain what happens to the particles and the bonds in the substance.
122 exam-style questions on OCR GCSE Chemistry 2.3 Properties of materials, covering 2.3.1 Carbon bonding and the variety of organic compounds, 2.3.2 Diamond, graphite, fullerenes and graphene, 2.3.3 Bond strength, changes of state and predicting states, 2.3.4 Bulk properties and types of bonding, and 2.3.5 Nanoparticles: scale, surface area, uses and risks. Each one has a worked solution and a mark scheme showing where the marks go.