- Kinetic particle model
- The model that explains the properties of solids, liquids and gases in terms of the arrangement and movement of particles.
- Change of state
- A physical change in which a substance changes from one state (solid, liquid, gas) to another. No new substances are formed.
- Melting point
- The temperature at which a substance changes from solid to liquid. It is the same temperature as the freezing point.
- Boiling point
- The temperature at which a substance changes from liquid to gas throughout its bulk.
- Sublimation
- The change of state directly from solid to gas without passing through a liquid stage.
- Forces of attraction
- The attractive forces between particles in a solid or liquid that hold them together. Stronger forces mean higher melting and boiling points.
This definitions covers Key Definitions within States of Matter for GCSE Chemistry. Revise States of Matter in Atomic Structure for GCSE Chemistry with 12 exam-style questions and 10 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 7 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for States of Matter
Which of the following best describes the arrangement of particles in a solid?
A heating curve shows a flat section (plateau) when a solid is being heated to become a liquid. Explain why the temperature does not rise during this flat section. [3 marks]
Quick recall flashcards
What are the three properties of a gas?
1. Particles are far apart and in a random arrangement.
2. Particles move quickly in random directions.
3. No fixed shape, no fixed volume — fills the container and can be compressed.
What are the three properties of a solid?
1. Particles are close together in a regular arrangement.
2. Particles only vibrate about fixed positions.
3. Definite shape and definite volume — cannot be compressed.