The nature of the substance, the particles that make up it, and the quantity of particles all stay unaltered after a physical change. Chemical changes result in new compounds with different properties from the original ones, as well as new particles and maybe altered particle numbers.
Physical and chemical changes
- A substance is said to undergo a physical change when only the physical properties such as the shape, size, colour or state of the substance change. No new substance is formed.
- Example: Melting of ice, boiling water.
- A substance is said to undergo a chemical change when a new substance with completely new properties (physical and chemical) is formed.
- Example: Burning of wood or paper, souring of milk.
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