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)

1. Which of the following are physical changes? (Select all that apply) (1 points)

2. Which of the following are chemical changes? (Select all that apply) (1 points)

3. What is a sign of a chemical change? (1 points)

4. Is dissolving salt in water a physical or chemical change? (1 points)

5. Which process is NOT a chemical change? (1 points)