Class8 Science Book Curiosity Chapter 7 QA
Chapter 7 – Particulate Nature of Matter
VERY SHORT ANSWER (1 MARK) – IMPORTANT
-
What is matter?
Matter is anything that has mass and occupies space. -
What is meant by particulate nature of matter?
Matter is made up of very tiny particles. -
Name the particles of matter.
Atoms and molecules. -
Do particles of matter have space between them?
Yes, particles of matter have spaces between them. -
Do particles of matter move?
Yes, particles of matter are in constant motion. -
What happens to particles on heating?
They move faster. -
Name the three states of matter.
Solid, liquid and gas.
SHORT ANSWER (2 MARKS) – IMPORTANT
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State two characteristics of particles of matter.
- Particles have spaces between them.
- Particles are in constant motion.
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Why does smell of perfume spread in a room?
Due to diffusion of particles in air. -
What is diffusion?
Diffusion is the intermixing of particles of one substance with another on their own. -
Why are solids rigid?
Because particles are closely packed and have strong forces of attraction. -
Why do gases fill the entire container?
Because particles of gases have large spaces and move freely. -
What happens to diffusion when temperature increases?
Diffusion becomes faster.
LONG ANSWER (5 MARKS) – IMPORTANT
1. Explain the characteristics of particles of matter.
Particles of matter are very small in size.
They have spaces between them.
They are in constant motion.
They attract each other with a force of attraction.
2. Explain the three states of matter.
Solid:
Particles are tightly packed, have fixed shape and volume.
Liquid:
Particles have less attraction, fixed volume but no fixed shape.
Gas:
Particles have very weak attraction, no fixed shape and volume.
3. What is diffusion? Explain with an example.
Diffusion is the process by which particles of one substance mix with particles of another substance on their own.
Example: Smell of incense stick spreads in air.
4. Effect of temperature on particles of matter.
On heating, particles gain energy and move faster.
On cooling, particles lose energy and move slower.
5. Differentiate between solids, liquids and gases.
| Solid | Liquid | Gas |
|---|---|---|
| Fixed shape | No fixed shape | No fixed shape |
| Fixed volume | Fixed volume | No fixed volume |
| Strong attraction | Moderate attraction | Weak attraction |
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