Physical change and chemical change definition with Examples

Physical change and chemical change definition:

A physical change is a change in a substance’s physical state or appearance, without changing its chemical composition. For example, melting ice, boiling water, and dissolving sugar in water are physical changes.

A chemical change, on the other hand, is a change in a substance’s chemical composition, resulting in the formation of a new substance or substances with different properties. For example, burning wood, rusting iron, and digesting food are all chemical changes because they involve the formation of new substances with different chemical properties.

In this article, we will explore the definitions of physical change and chemical change in detail, accompanied by examples to aid in comprehension.”

Physical change Definition & Examples

A physical change is a change in a substance’s physical state or appearance, without changing its chemical composition. Examples of physical changes include:

  1. Change of state: When a substance changes from one state to another, it is a physical change. For example, melting of ice to form water, boiling of water to form steam, and condensing of steam to form water are all physical changes.
  2. Change in size or shape: When the size or shape of an object changes, it is a physical change. For example, cutting a piece of paper into smaller pieces or stretching a rubber band are physical changes.
  3. Change in color: When the color of a substance changes, it is a physical change. For example, when a piece of paper turns yellow due to exposure to sunlight, it is a physical change.
  4. Change in texture: When the texture of a substance changes, it is a physical change. For example, when dough is kneaded to make bread, it is a physical change.
  5. Change in density: When the density of a substance changes, it is a physical change. For example, when sugar dissolves in water, it is a physical change as the volume of the solution increases but the mass remains the same.

In all these examples, the chemical composition of the substance remains the same, and only its physical properties change.

Chemical change definition & examples

A chemical change is a change in the chemical composition of a substance, resulting in the formation of a new substance or substances with different properties. Examples of chemical changes include:

  1. Combustion: When a substance reacts with oxygen to produce heat and light, it is a chemical change. For example, burning of wood to produce ash and smoke is a chemical change.
  2. Oxidation: When a substance reacts with oxygen to produce a new compound, it is a chemical change. For example, rusting of iron is a chemical change.
  3. Decomposition: When a compound breaks down into simpler substances, it is a chemical change. For example, decomposition of hydrogen peroxide into water and oxygen gas is a chemical change.
  4. Digestion: When food is broken down in the digestive system to produce energy, it is a chemical change. For example, digestion of carbohydrates to produce glucose is a chemical change.
  5. Fermentation: When sugar is broken down by yeast to produce alcohol, it is a chemical change.

In all these examples, the chemical composition of the substance changes, resulting in the formation of a new substance with different chemical properties.

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