Physical and Chemical Changes

Defining Physical vs. Chemical Changes00:00:01

Physical changes occur without changing the chemical identity of a substance, while chemical changes involve the formation of new substances with different chemical formulas.

Examples of Physical Changes00:00:26

Crumpling paper, freezing liquid water into ice, boiling, and drawing copper metal into wire are all physical changes because the substance remains fundamentally the same.

Examples of Chemical Changes00:00:45

Burning paper or gasoline, the electrolysis of water, and metallic corrosion like rusting are chemical changes because they transform the substance into entirely new chemical products.

Indicators of Chemical Changes00:05:34

A sudden change in color in a solution, the presence of corrosion, or the tarnishing of metals like silver indicates a chemical reaction and a change in chemical identity.

States of Matter and Phase Changes00:06:26

Phase transitions such as vaporization, condensation, sublimation, and deposition are classified as physical changes as they only alter the state of matter, not the molecular identity.