A chemical change, also known as a chemical reaction, is a process in which one or more substances undergo a transformation to form new substances with different properties. This type of change is permanent, and it is always accompanied by the formation of one or more new substances. Some common examples of chemical changes include:
- Digestion of food
- Burning of coal
- Rusting of iron
In contrast, physical changes are temporary and only affect the physical properties of a substance, such as its shape or size. Physical changes do not involve the formation of new substances or the breaking of chemical bonds. Some examples of physical changes are:
- Freezing of water
- Melting of wax
- Boiling of water
Understanding the difference between physical and chemical changes is important because chemical changes often involve the production of energy, while physical changes do not. Additionally, chemical changes require a molecular-level rearrangement of atoms and cannot be easily reversed, while physical changes can be reversed by simple processes like heating or cooling.
