✅ True or False (10 Questions)

1. Matter is composed of extremely small particles.
   True hecu107

2. A chalk stick is made up of only one single particle.
   False
   (It is made up of a large number of constituent particles.) hecu107

3. Grinding chalk is an example of a chemical change.
   False
   (Grinding is a physical change; only size changes.) hecu107

4. Sugar dissolves in water because its particles occupy interparticle spaces between water particles.
   True hecu107

5. Interparticle spaces are completely filled with air.
   False
   (Interparticle spaces contain nothing.) hecu107

6. Solids have a definite shape and volume due to strong interparticle attractions.
   True hecu107

7. Liquids have a fixed shape but no fixed volume.
   False
   (Liquids have fixed volume but no fixed shape.) hecu107

8. The boiling point is the temperature at which a liquid turns into vapour rapidly.
   True hecu107

9. Gases have negligible interparticle attraction and fill all available space.
   True hecu107

10. Potassium permanganate spreads in water because particles of water are in constant motion.
    True

✅ Fill in the Blanks (10 Questions)

1. Matter is made up of extremely small __________.
   Answer: particles hecu107

2. The particles that make up matter are called __________ particles.
   Answer: constituent hecu107

3. There are __________ spaces between the particles of matter.
   Answer: interparticle hecu107

4. Sugar dissolves in water because sugar particles occupy the __________ spaces between water particles.
   Answer: interparticle hecu107

5. The force that holds particles together is called interparticle __________.
   Answer: attraction hecu107

6. Solids have a fixed shape and volume due to __________ attraction between particles.
   Answer: strong hecu107

7. Liquids have fixed volume but do not have a fixed __________.
   Answer: shape hecu107

8. Gases have neither fixed shape nor fixed __________.
   Answer: volume hecu107

9. The spreading of particles from one region to another is called __________.
   Answer: diffusion hecu107

10. Potassium permanganate spreads in water because particles are in constant __________.
    Answer: motion

✅ Multiple Choice Questions (15 MCQs)

1. Matter is made up of:

A. Only water
B. Large continuous mass
C. Extremely small particles
D. Only atoms of metals
✅ Answer: C hecu107

2. The particles of matter are:

A. Stationary
B. Always in motion
C. Only visible under microscope
D. Very large
✅ Answer: B hecu107

3. Sugar dissolves in water because:

A. Sugar disappears
B. Sugar reacts chemically
C. Sugar particles occupy spaces between water particles
D. Water evaporates
✅ Answer: C hecu107

4. Solids have fixed shape because:

A. Particles have no attraction
B. Particles are far apart
C. Particles have strong attraction
D. Particles can move freely
✅ Answer: C hecu107

5. Liquids can flow because:

A. Particles are tightly packed
B. Particles can slide over each other
C. Particles are fixed
D. Liquids have no particles
✅ Answer: B hecu107

6. Gases fill the entire space because:

A. Particles have strong attraction
B. Particles are closely packed
C. Particles move freely with negligible attraction
D. Gases have fixed shape
✅ Answer: C hecu107

7. Interparticle spaces are maximum in:

A. Solids
B. Liquids
C. Gases
D. Metals
✅ Answer: C hecu107

8. The force that holds particles together is called:

A. Gravity
B. Interparticle attraction
C. Diffusion
D. Reflection
✅ Answer: B hecu107

9. Diffusion is fastest in:

A. Solids
B. Liquids
C. Gases
D. Ice
✅ Answer: C hecu107

10. Potassium permanganate spreads in water due to:

A. Reflection
B. Diffusion
C. Freezing
D. Melting
✅ Answer: B hecu107

11. The temperature at which liquid changes rapidly into vapour is called:

A. Melting point
B. Boiling point
C. Freezing point
D. Condensation point
✅ Answer: B hecu107

12. Solids are:

A. Easily compressible
B. Not compressible
C. Highly compressible
D. Always gaseous
✅ Answer: B hecu107

13. Liquids have:

A. Fixed shape and volume
B. Fixed volume but no fixed shape
C. Fixed shape but no volume
D. Neither shape nor volume
✅ Answer: B hecu107

14. The smell of incense spreads in air because of:

A. Melting
B. Diffusion
C. Reflection
D. Freezing
✅ Answer: B hecu107

15. The particles in solids:

A. Are far apart
B. Have very weak attraction
C. Vibrate about fixed positions
D. Move freely in all directions
✅ Answer: C

✅ Assertion–Reason Questions (10)

Directions: Choose the correct option:

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

1.

Assertion (A): Matter is made up of extremely small particles.
Reason (R): These particles cannot be seen easily with naked eyes.
✅ Answer: B hecu107

2.

Assertion (A): Sugar dissolves in water without increasing the water level significantly.
Reason (R): Sugar particles occupy interparticle spaces between water particles.
✅ Answer: A hecu107

3.

Assertion (A): Solids have fixed shape and volume.
Reason (R): Solids have strong interparticle attraction and very small spaces.
✅ Answer: A hecu107

4.

Assertion (A): Liquids do not have a fixed shape.
Reason (R): Liquid particles can move and slide over one another.
✅ Answer: A hecu107

5.

Assertion (A): Gases can be compressed easily.
Reason (R): Gas particles have large interparticle spaces.
✅ Answer: A hecu107

6.

Assertion (A): Diffusion is fastest in gases.
Reason (R): Gas particles move freely and have negligible attraction.
✅ Answer: A hecu107

7.

Assertion (A): Potassium permanganate spreads in water even without stirring.
Reason (R): Particles of matter are in constant motion.
✅ Answer: A hecu107

8.

Assertion (A): Solids are not easily compressible.
Reason (R): Particles in solids are tightly packed with strong attraction.
✅ Answer: A hecu107

9.

Assertion (A): Boiling point is the temperature at which a liquid changes rapidly into vapour.
Reason (R): At boiling point, particles gain enough energy to overcome attraction.
✅ Answer: A hecu107

10.

Assertion (A): The smell of perfume spreads across a room.
Reason (R): Diffusion occurs due to the random motion of gas particles.
✅ Answer: A

✅ Very Short Answer Questions (10 Questions)

(2 Marks Each | CBSE Class 8 Standard | Good Quality)

1. What is meant by particulate nature of matter?

Answer:
Particulate nature of matter means that all matter is made up of extremely small particles called constituent particles. hecu107

2. What are constituent particles?

Answer:
Constituent particles are the tiny particles that make up matter, such as atoms or molecules. hecu107

3. Why does sugar dissolve in water without increasing its volume much?

Answer:
Sugar particles occupy the interparticle spaces between water particles, so the water level does not increase significantly. hecu107

4. Define interparticle attraction.

Answer:
Interparticle attraction is the force of attraction between particles of matter that holds them together. hecu107

5. Why do solids have a fixed shape?

Answer:
Solids have a fixed shape because their particles are tightly packed with strong interparticle attraction. hecu107

6. Why do liquids take the shape of their container?

Answer:
Liquids take the shape of their container because their particles can move and slide over each other. hecu107

7. Why do gases fill the entire container?

Answer:
Gases fill the entire container because their particles move freely in all directions and have negligible attraction. hecu107

8. What is diffusion?

Answer:
Diffusion is the spreading of particles from a region of higher concentration to a region of lower concentration due to their constant motion. hecu107

9. Why is diffusion fastest in gases?

Answer:
Diffusion is fastest in gases because gas particles move rapidly and have large spaces between them. hecu107

10. Give one example of diffusion in daily life.

Answer:
The spreading of perfume smell in a room is an example of diffusion in gases.

✅ Short Answer Questions (10 Questions)

(3 Marks Each | CBSE Class 8 Standard | Good Quality)

1. Explain how the activity of dissolving sugar in water proves the particulate nature of matter.

Answer:
When sugar is dissolved in water, the sugar particles occupy the spaces between water particles. The water level does not rise much, showing that matter has interparticle spaces and is made of tiny particles. hecu107

2. Differentiate between solids, liquids, and gases on the basis of shape and volume.

Answer:
Solids have fixed shape and fixed volume. Liquids have fixed volume but no fixed shape, so they take the shape of the container. Gases have neither fixed shape nor fixed volume and fill the entire container. hecu107

3. Why are solids not easily compressible?

Answer:
Solids are not easily compressible because their particles are tightly packed with very small interparticle spaces and strong attraction between particles. hecu107

4. Why can liquids flow but solids cannot?

Answer:
Liquids can flow because their particles can move and slide over each other. In solids, particles are fixed in position due to strong attraction, so solids cannot flow. hecu107

5. Explain why gases can be compressed easily.

Answer:
Gases have very large interparticle spaces and weak attraction between particles. Therefore, gas particles can be pushed closer together, making gases highly compressible. hecu107

6. What is diffusion? Explain with an example.

Answer:
Diffusion is the spreading of particles from a region of higher concentration to lower concentration due to constant motion. Example: Smell of perfume spreads throughout a room. hecu107

7. Why is diffusion slow in solids but fast in gases?

Answer:
In solids, particles are tightly packed and can only vibrate, so diffusion is very slow. In gases, particles move freely with large spaces, so diffusion is very fast. hecu107

8. How does temperature affect diffusion?

Answer:
Diffusion increases with rise in temperature because particles gain more kinetic energy and move faster, spreading more quickly. hecu107

9. What is boiling point? Why does boiling occur?

Answer:
Boiling point is the temperature at which a liquid changes rapidly into vapour. Boiling occurs when particles gain enough energy to overcome interparticle attraction and escape as gas. hecu107

10. How do interparticle attractions decide the state of matter?

Answer:
Strong attraction leads to solids with fixed shape. Moderate attraction leads to liquids that can flow. Negligible attraction leads to gases that move freely and fill space. Thus, interparticle attraction decides the state of matter.

✅ Case-Based Questions (4 Cases)

(4 Marks Each | Sub-questions: 1 + 1 + 2 Marks)
CBSE Competency-Based Standard

Case 1: Dissolving Sugar in Water

A student adds sugar to a glass of water and stirs it. The sugar disappears, but the water level does not rise much.

Questions:

Q1. (1 Mark) What does this activity show about matter?
Answer: Matter has interparticle spaces. hecu107

Q2. (1 Mark) What happens to sugar particles when dissolved?
Answer: They occupy spaces between water particles. hecu107

Q3. (2 Marks) Why does the water level not increase significantly?
Answer:
Because sugar particles fit into the interparticle spaces of water, showing that matter is made of tiny particles with spaces between them. hecu107

Case 2: Properties of Solids

A chalk stick retains its shape even when moved from one place to another. It is hard and cannot be compressed easily.

Questions:

Q1. (1 Mark) What is the shape of a solid like chalk?
Answer: Fixed shape hecu107

Q2. (1 Mark) Are solids easily compressible?
Answer: No hecu107

Q3. (2 Marks) Why are solids not easily compressible?
Answer:
Because particles in solids are tightly packed with strong interparticle attraction and very small spaces. hecu107

Case 3: Diffusion in Gases

The smell of incense spreads quickly throughout a room even though it is lit in only one corner.

Questions:

Q1. (1 Mark) Name the process responsible for spreading smell.
Answer: Diffusion hecu107

Q2. (1 Mark) In which state of matter is diffusion fastest?
Answer: Gases hecu107

Q3. (2 Marks) Why does diffusion occur quickly in gases?
Answer:
Because gas particles move freely with high speed and have large interparticle spaces, so they spread rapidly. hecu107

Case 4: Boiling of Water

When water is heated, it starts boiling at 100°C and changes rapidly into steam.

Questions:

Q1. (1 Mark) What is the boiling point of water?
Answer: 100°C hecu107

Q2. (1 Mark) What happens to water at boiling point?
Answer: It changes rapidly into vapour. hecu107

Q3. (2 Marks) Why does boiling occur at a fixed temperature?
Answer:
At boiling point, particles gain enough energy to overcome interparticle attraction and escape as vapour, causing rapid change of liquid into gas.

✅ Long Answer Questions (5 Questions)

(5 Marks Each | CBSE Class 8 Standard | High Quality Answers)

1. Explain the particulate nature of matter with examples.

Answer:
The particulate nature of matter means that matter is made up of extremely small particles called constituent particles.

Evidence of particulate nature:

• Grinding chalk: Chalk breaks into smaller particles, showing it is made of tiny particles.
• Dissolving sugar in water: Sugar particles occupy spaces between water particles, proving the presence of interparticle spaces.
• Diffusion: Smell of perfume spreads in air due to motion of particles.

Thus, matter consists of tiny particles with spaces between them and these particles are always in motion. hecu107

2. Describe the properties of solids, liquids, and gases based on particle arrangement.

Answer:

Solids

• Particles are tightly packed with strong attraction.
• Fixed shape and fixed volume.
• Not easily compressible.

Liquids

• Particles are less tightly packed with moderate attraction.
• Fixed volume but no fixed shape.
• Can flow easily.

Gases

• Particles are far apart with negligible attraction.
• No fixed shape and no fixed volume.
• Highly compressible and fill the container.

Thus, particle arrangement decides the properties of each state of matter. hecu107

3. Explain interparticle spaces and attractions and how they affect the state of matter.

Answer:
Particles of matter have spaces between them called interparticle spaces.

• In solids, spaces are very small and attraction is strong, so particles remain fixed.
• In liquids, spaces are larger and attraction is moderate, allowing particles to slide.
• In gases, spaces are maximum and attraction is negligible, so particles move freely.

Therefore, the size of interparticle spaces and the strength of attraction decide whether matter exists as solid, liquid, or gas. hecu107

4. What is diffusion? Explain why diffusion is fastest in gases.

Answer:
Diffusion is the spreading of particles from a region of higher concentration to lower concentration due to their constant random motion.

Diffusion is fastest in gases because:

• Gas particles move very rapidly.
• They have large interparticle spaces.
• Interparticle attraction is very weak.

Example: Smell of incense spreads quickly throughout a room due to diffusion in gases. hecu107

5. Explain boiling point and change of state with particle motion.

Answer:
Boiling point is the temperature at which a liquid changes rapidly into vapour.

At boiling point:

• Liquid particles gain enough kinetic energy.
• They overcome interparticle attraction.
• They move freely as gas particles.

For example, water boils at 100°C and changes into steam.

Thus, change of state occurs due to increased particle motion and decreased attraction between particles.