Chemical change

A chemical change is a sign that indicates that a chemical reaction has occurred.

Chemical changes include

• The production of a gas. Eg. Fizz from sherbet
• A permanent color change. Eg. A red solution changing to a colorless solution
• The production of light. Eg. Glow in the dark light sticks which is an example of chemiluminesce
• The production of a flame. Eg. A Bunsen burner
• The dissolving of an insoluble solid. Eg. Magnesium dissolving in acid.
• The production of an insoluble solid. Eg. The production of a precipitate

These changes indicate that something new has been produced.

Physical changes on the other hand are easy to reverse and don't produce anything new. They only involve a change in the physical states (solid. liquid and gas). eg. the melting of an ice cube and steam being produced from a kettle.