Theory Exercises

Physical and Chemical Changes: More Examples and Explanations

Physical Changes

Physical changes do not alter the chemical identity of a substance. They include changes of state (solid, liquid, gas), shape, or size. For example, when ice melts to water, it is still H₂O. No new substance is formed.

Other examples:
  • Crushing a can
  • Chopping wood
  • Stretching a rubber band

Chemical Changes

Chemical changes result in new substances with different properties. Atoms are rearranged, and the process is often not easily reversible.

Other examples:
  • Digesting food (enzymes break down molecules)
  • Milk souring (bacteria produce new chemicals)
  • Fireworks exploding (new gases and colors produced)