Key learning points

1. There are changes in arrangement, movement and energy of particles during state changes.
2. There are two types of change, physical and chemical, and these can be explained in terms of the particle model.
3. The physical state of a substance can be predicted at specified temperatures.
4. Forces of attraction between particles have a role in determining the amount of energy needed for state changes.

Keywords

• Physical change - A change in which no new substances are formed, such as a change in state, e.g. melting.

• Chemical change - When a reaction takes place and atoms or ions in the reactants are rearranged to make new products/substances.

Common misconception