Chapter 1: Matter in Our Surroundings Short Questions | science Class 9 CBSE

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Chapter 1: Matter in Our Surroundings Short Questions | science Class 9 CBSE | ByteNotes.in

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Question 1

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Q1. Define matter.

Matter is anything that occupies space and has mass.
All substances around us are forms of matter.
Examples: air, water, wood, and metals.

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Question 2

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Q2. What is diffusion?

Intermixing of particles of two substances.
Occurs in gases and liquids due to particle motion.
Example: fragrance spreading in air.

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Question 3

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Q3. Name the three states of matter.

Solid – has fixed shape and volume.
Liquid – fixed volume but no fixed shape.
Gas – neither fixed shape nor volume.

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Question 4

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Q4. What is latent heat of vaporisation?

Heat required to convert liquid into gas at boiling point.
Absorbed without temperature change.
Measured in J/kg.

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Question 5

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Q5. Mention any two factors affecting evaporation.

Surface area – more area increases evaporation.
Humidity – more humidity reduces evaporation.
Other factors: temperature and wind speed.

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Question 6

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Q6. What is sublimation?

Change from solid directly to gas without becoming liquid.
Example: camphor, naphthalene, dry ice.
Reverse is called deposition.

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Question 7

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Q7. Define boiling point.

Temperature at which a liquid boils and changes into vapour.
Boiling point of water is 100°C at 1 atm pressure.
Remains constant during phase change.

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Question 8

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Q8. What is condensation?

Change of state from gas to liquid on cooling.
Opposite of vaporisation.
Releases latent heat.

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Question 9

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Q9. Why does evaporation cause cooling?

High-energy particles escape during evaporation.
Reduces average energy of remaining particles.
Thus, causes cooling effect.

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Question 10

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Q10. Give one example each of solid, liquid, and gas.

Solid – Ice.
Liquid – Water.
Gas – Air.

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Chapter sections

Chapter 1: Matter in Our Surroundings | Short Questions

Q1. Define matter.

Q2. What is diffusion?

Q3. Name the three states of matter.

Q4. What is latent heat of vaporisation?

Q5. Mention any two factors affecting evaporation.

Q6. What is sublimation?

Q7. Define boiling point.

Q8. What is condensation?

Q9. Why does evaporation cause cooling?

Q10. Give one example each of solid, liquid, and gas.