Explanation of Chemistry Chapter 1 Question 12

Question: What is the difference between physical and chemical change? Give examples.

Answer:

Physical and chemical changes are two types of changes that can occur in matter. These changes are important to understand because they affect the properties and behavior of matter. In this answer, we will explain the difference between physical and chemical changes and provide examples of each.

Physical Changes

Physical changes are changes that do not alter the chemical composition of a substance. These changes can be observed without changing the substance into a new substance. Physical changes include changes in shape, size, phase, and state.

Examples of physical changes include:

- Melting ice into water
- Boiling water into steam
- Cutting a piece of paper into smaller pieces
- Crushing a can
- Changing the color of a substance
- Dissolving sugar in water

Chemical Changes

Chemical changes are changes that alter the chemical composition of a substance. These changes cannot be observed without changing the substance into a new substance. Chemical changes involve the breaking and forming of chemical bonds.

Examples of chemical changes include:

- Burning wood into ash
- Rusting of iron
- Digestion of food
- Photosynthesis in plants
- Tarnishing of silver
- Cooking an egg

Differences between Physical and Chemical Changes

The main differences between physical and chemical changes are:

- Physical changes do not alter the chemical composition of a substance, while chemical changes do.
- Physical changes can be observed without changing the substance into a new substance, while chemical changes cannot.
- Physical changes involve changes in shape, size, phase, and state, while chemical changes involve the breaking and forming of chemical bonds.

In conclusion, physical and chemical changes are two types of changes that can occur in matter. Physical changes involve changes in shape, size, phase, and state, while chemical changes involve the breaking and forming of chemical bonds. It is important to understand these differences because they affect the properties and behavior of matter.