Matter Notes: Pure Substances, Mixtures, and Changes

Vocabulary flashcards covering key concepts from the notes on matter, pure substances, mixtures, and changes.

Matter

Anything that has mass and occupies space; exists as pure substances or mixtures.

Pure substance

A substance with a uniform composition that cannot be separated into other substances by physical methods.

Element

A pure substance that cannot be broken down into simpler substances by chemical means.

Compound

A pure substance formed from two or more elements chemically combined in fixed proportions; can be decomposed by chemical means.

Mixture

A combination of two or more substances that are not chemically combined; can be homogeneous or heterogeneous.

Homogeneous mixture

A mixture with uniform composition throughout; components are evenly distributed.

Heterogeneous mixture

A mixture with non-uniform composition; components are not evenly distributed.

Physical change

A change in which the chemical identity of a substance is not changed; often used to separate mixtures.

Chemical change

A change that produces new substances; involves breaking and forming chemical bonds (e.g., decomposition of compounds).