Resources | Subject Notes | Physics
This section explores the three common states of matter: solid, liquid, and gas. We will examine their distinguishing properties and how they differ.
The three states of matter are distinguished by their arrangement of particles (atoms or molecules) and the strength of the forces between them.
| Property | Solid | Liquid | Gas |
|---|---|---|---|
| Shape | Definite | Indefinite (takes the shape of the container) | Indefinite (fills the entire container) |
| Volume | Definite | Definite | Indefinite (fills the entire container) |
| Particle Arrangement | Close packed, ordered | Close packed, random | Far apart, random |
| Particle Motion | Vibrate in fixed positions | Vibrate and slide past each other | Move randomly and rapidly |
| Compressibility | Very low | Low | High |
| Strength of Intermolecular Forces | Very strong | Moderate | Very weak |
Solids have a fixed shape and volume because their particles are tightly packed in a regular arrangement and held together by strong intermolecular forces. The particles vibrate about their fixed positions but do not move past each other easily.
Liquids have a definite volume but take the shape of their container. Their particles are close packed but arranged randomly, and the intermolecular forces are weaker than in solids, allowing particles to move past each other.
Gases have neither a definite shape nor a definite volume. They fill the entire volume of their container. Their particles are far apart and move randomly and rapidly. The intermolecular forces are very weak.
Matter can change between its three states through processes called phase changes. These changes occur when the temperature or pressure is altered.
The temperature at which these phase changes occur are characteristic of the substance and are often referred to as melting point, freezing point, boiling point, and condensation point.