The Classification of Matter.A

Vocabulary flashcards covering physical and chemical properties, elements, compounds, mixtures, states of matter, and phase changes.

Physical Properties

Characteristics that describe matter—such as size, shape, color, and mass—which can be observed or measured without changing the identity of the matter in question.

Chemical Properties

Characteristics that describe how matter changes its chemical structure or composition, such as flammability, where observation involves a chemical change resulting in matter with a different identity.

Substance

Any sample of matter that has the same physical and chemical properties throughout the sample.

Element

A substance that cannot be broken down into chemically simpler components, represented by symbols like Al for aluminum, with about $118$ known in the universe.

Compound

A substance that can be broken down into chemically simpler components because it consists of more than one element, such as water ($H_2O$).

Atom

The smallest part of an element that maintains the identity of that element, so tiny that making a $1\text{ inch}$ line of iron atoms requires approximately $217\text{ million}$ iron atoms.

Molecule

The smallest part of a compound that maintains the identity of that compound, composed of two or more atoms attached together that behave as a unit.

Macroscopic Viewpoint

The perspective studied when a scientist works with large numbers of atoms or molecules at a time.

Microscopic Viewpoint

The perspective studied when describing chemical events on the level of individual atoms or molecules.

Mixture

A material composed of two or more substances in which the individual substances maintain their chemical identities.

Heterogeneous Mixture

A mixture consisting of obvious combinations of two or more substances where individual components maintain their distinct identities, such as sand and water, soil, or an egg.

Homogeneous Mixture

A mixture with a consistent or uniform composition throughout whose components act like a single substance, also called a solution, such as saltwater, steel, or air.

Solid

A physical state or phase of matter that has a fixed shape and a fixed volume.

Liquid

A physical state or phase of matter that has a fixed volume but not a fixed shape, forming a horizontal surface and taking the shape of its container.

Gas

A physical state or phase of matter that has neither a fixed shape nor a fixed volume and expands to fill its container.

Phase Change

A physical process in which a substance changes from one physical state to another, typically caused by varying temperature or pressure.

Melting (Fusion)

The phase change of a substance from a solid state to a liquid state.

Sublimation

The phase change of a substance directly from a solid state to a gas state.

Boiling (Evaporation)

The phase change of a substance from a liquid state to a gas state.

Solidification (Freezing)

The phase change of a substance from a liquid state to a solid state.

Condensation

The phase change of a substance from a gas state to a liquid state.

Deposition

The phase change of a substance directly from a gas state to a solid state.