Composition of Matter and Changes

Flashcards covering key vocabulary terms and concepts related to the composition of matter and changes.

Element

A substance that consists of atoms with the same identity.

Compound

A substance formed when two or more different atoms combine chemically.

Molecule

A group of two or more like atoms combined chemically.

Mixture

A material made up of two or more substances that can be easily separated by physical means.

Heterogeneous mixture

A mixture in which different materials can be distinguished easily.

Homogeneous mixture

A mixture containing two or more substances blended evenly throughout, also referred to as a solution.

Solution

A homogeneous mixture of particles so small that they cannot be seen with a microscope and will never settle to the bottom.

Physical Change

A change that affects one or more physical properties of a substance but does not change its identity.

Chemical Change

The formation of a new substance from a chemical reaction that is irreversible.

Physical Properties

Characteristics of a substance that can be observed without changing its identity.

Examples of Physical Changes

Bending, crushing, breaking, dissolving, and phase changes such as boiling and melting.

Examples of Chemical Changes

Temperature change, color change, production of gas (bubbles/fizzing), and production of smoke.