Question

8. Classify the following changes in as many ways as you can:

Breaking of a brick with a hammer.

Beating of heart.

Germination of a seed.

Burning of an incense-stick (agarbatti).

Occurrence of so​

Answer 1

Answer:

1) Physical change, irreversible change.

2)Periodic change, irreversible change.

3)Irreversible change,

4)Irreversible change, chemical change.

5)Irreversible change.

Answer 2

THE CHANGES CAN BE CLASSIFIED AS -

1. Breaking of a brick with a hammer - Physical change, Reversible change.

2. Beating of heart - Physical change, Irreversible change.

3. Germination of a seed - Chemical change, Irreversible change.

4. Burning of an incense stick - Chemical change, Irreversible change.

Explanation -

CHANGES AROUND US -

• There are different types of changes occurring around us -

1. Physical changes

• Temporary changes in which composition remains the same.
• The arrangement of molecules in the compound changes.
• Physical properties changes such as shape, size, color.
• Less energy is involved during the process.
• Example - Melting of ice, Burning of candle, boiling of water.

2. Chemical change

• Permanent changes in which both physical and chemical of the product changes.
• Energy is utilised during the reaction.
• A new substance is formed after the reaction.
• Example - Digestion of food, rusting of iron, burning of coal, burning of incense stick.

3. Reversible reactions

• Reactions that can be reversed back to their original state.
• Reactants are modified to other forms and no new substance is formed.
• Reactions are temporary in nature.
• Example - Freezing of ice, burning of the candle.

4. Irreversible Change

• A permanent type of reactions that cannot be reversed back to their original state.
• A new substance is formed from the reacting species.
• The reaction is known as a one-way reaction.
• Example - Burning of paper, burning of an incense stick.