States of Matter & Phase Changes Cheat Sheet

Key Facts

• A solid has a definite shape and definite volume because its particles vibrate in fixed positions.
• A liquid has a definite volume but no definite shape because its particles slide past one another.
• A gas has no definite shape and no definite volume because its particles move freely and spread out to fill a container.
• Plasma is an ionized gas with charged particles, often found in lightning, stars, and some neon signs.
• Density is calculated with $D = \frac{m}{V}$, where $D$ is density, $m$ is mass, and $V$ is volume.
• Temperature change within one state uses $q = mc\Delta T$, where $q$ is heat energy, $m$ is mass, $c$ is specific heat, and $\Delta T = T_{\text{final}} - T_{\text{initial}}$.
• Energy during a phase change uses $q = mL$, where $L$ is latent heat and temperature stays constant during the change.
• Melting, vaporization, and sublimation absorb energy, while freezing, condensation, and deposition release energy.

Vocabulary

Solid

A state of matter with a definite shape and definite volume because particles are closely packed and vibrate in place.

Liquid

A state of matter with a definite volume but no definite shape because particles can flow around one another.

Gas

A state of matter with no definite shape or volume because particles move quickly and spread far apart.

Plasma

A high-energy state of matter made of charged particles, often formed when a gas gains enough energy to become ionized.

Phase Change

A physical change in which a substance changes from one state of matter to another without becoming a new substance.

Latent Heat

The energy absorbed or released during a phase change while the temperature remains constant.