States of Matter

Gases consist of particles that are far apart and move randomly, allowing them to expand to fill any container.

Liquids have a definite volume because the particles are close together, but they lack a definite shape because the particles can slide past one another.

Solids have particles held in fixed positions, giving them both a definite shape and a definite volume.

The heat of fusion is the energy required to change a substance from a solid to a liquid at its melting point.

Boiling is the process where a liquid changes to a gas throughout the substance at a specific temperature.

Melting is the phase transition where a solid gains enough thermal energy to overcome the forces holding it in a rigid structure, turning it into a liquid.

Condensation occurs when gas particles lose kinetic energy and slow down enough for intermolecular forces to pull them together into a liquid state.

A liquid has a fixed volume because the particles are close together, but it lacks a fixed shape because the particles can slide past one another.

A substance is a form of matter that has a constant chemical composition and characteristic properties.

Freezing is the phase change where a liquid loses enough thermal energy to become a solid.

Atoms are the basic particles of matter. Everything in the physical universe, whether living or nonliving, is composed of these fundamental units.

Potable water is water that is safe enough to be consumed by humans or used with low risk of immediate or long-term harm.

Evaporation is the process where liquid water turns into water vapor (gas) due to heat. Condensation is the opposite, where gas turns into liquid.

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid.