Chemical and Physical Changes

A chemical change is a process that alters the identity of a substance, resulting in the formation of one or more new substances.

A physical change is a process that does not alter the identity of a substance; the substance remains the same even though its form may change.

Rusting of a nail is an example of a chemical change.

Melting of an ice cube is an example of a physical change.

The identity of the substance changes during a chemical change.

The identity of the substance remains the same during a physical change.

Copper tarnishing is an example of a chemical change.

An indicator of a chemical change can include color change, gas production, or the formation of a precipitate.

An indicator of a physical change can include changes in state, such as melting or freezing.

Chemical changes are often not reversible, unlike physical changes which can usually be reversed.