Chemical and Physical Changes

A chemical change is a process where substances combine or break apart to form new substances with different properties. Examples include baking, rusting, and burning.

A physical change is a process that alters the form or appearance of a substance but does not change its chemical composition. Examples include melting, freezing, and crushing.

Chemical Change

Physical Change

During a chemical change, bonds between atoms are broken and new bonds are formed, resulting in the creation of new substances.

During a physical change, the substance may change its state or appearance, but its chemical identity remains the same.

An example of a chemical change is copper tarnishing, where copper reacts with oxygen to form copper oxide.

An example of a physical change is melting ice into water, where the substance remains H2O.

Indicators of a chemical change include color change, temperature change, gas production, and the formation of a precipitate.

Indicators of a physical change include changes in state (solid, liquid, gas), shape, or size without altering the substance's chemical identity.