STATES OF MATTER

Matter is anything that has mass and occupies space. Matter exists in different physical forms called states of matter.

🔬 Particle Nature of Matter

Matter is made up of tiny particles.

Characteristics of Particles:

  • Have spaces between them

  • Are constantly moving

  • Attract each other

Change of State

Matter can change from one state to another by changing:

  • Temperature

  • Pressure

🔹 Effect of Temperature

Increasing temperature:

  • Increases particle movement

  • Reduces force of attraction

  • Causes expansion

🔹 Effect of Pressure

Increasing pressure:

  • Brings particles closer

  • Can convert gas into liquid

🔹 Three Main States of Matter




Studyhub24


1️⃣ Solid

  • Fixed shape

  • Fixed volume

  • Particles are tightly packed

  • Very strong force of attraction

Examples: Ice, Wood, Iron


2️⃣ Liquid

  • No fixed shape (takes container’s shape)

  • Fixed volume

  • Particles are less tightly packed

Examples: Water, Oil, Milk


3️⃣ Gas

  • No fixed shape

  • No fixed volume

  • Particles are very far apart

  • Very weak force of attraction

Examples: Oxygen, Carbon dioxide, Air

Important Processes:

  

       Change

Process Name

       Solid →  Liquid

 Melting

       Liquid →Solid.                

Freezing

       Liquid → Gas

Evaporation / Boiling

      Gas → Liquid

Condensation

      Solid → Gas

Sublimation


🌫️ Plasma (Fourth State of Matter)

  • Found in Sun and stars

  • Consists of ionized gases

  • Conducts electricity

❄️ Bose–Einstein Condensate (Fifth State)

  • Formed at extremely low temperature

  • Atoms move very slowly

  • Behaves like a single super atom

📊 Properties Comparison Table

   

Property

Solid

Liquid

     Gas

Shape.                       

Fixed               

Not fixed

     Not fixed

Volume

Fixed

Fixed

     Not fixed

Density

High

Medium

     Low

Compressibility

Negligible

Low

     High

Diffusion

Very slow

Slow.             

     Fast


🧪 Gas Laws

Boyle’s Law

Pressure inversely proportional to volume (at constant temperature).

Charles’ Law

Volume directly proportional to temperature (at constant pressure).

Avogadro’s Law

Equal volumes of gases contain equal number of molecules (at same temp & pressure).



1. Very Short Answer Questions (1–2 Marks)

  1. What are the three states of matter?

  2. Define matter.

  3. What is diffusion?

  4. What is evaporation?

  5. What is condensation?

  6. Why do gases fill the entire container?

  7. Why do solids have a fixed shape?

  8. What is melting point?

  9. What is boiling point?

  10. Why are gases highly compressible?

2. Short Answer Questions (2–3 Marks)

  1. Explain the properties of solids.

  2. Write two differences between solids and liquids.

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

  4. Explain the process of evaporation with examples.

  5. What factors affect evaporation?

  6. Explain diffusion in gases with an example.

  7. Why do solids have strong intermolecular forces?

  8. What is the difference between boiling and evaporation?

3. Long Answer Questions (4–5 Marks)

  1. Explain the three states of matter with their properties and examples.

  2. Describe the changes of state of matter with a diagram.

  3. Explain melting, freezing, boiling and condensation.

  4. Describe the particle nature of matter.

  5. Explain sublimation with examples.

4. Important Numerical / Application Questions

  1. Why do clothes dry faster on a windy day?

  2. Why do we feel cool when sweat evaporates?

  3. Why can gases be compressed but solids cannot?

  4. Why does perfume smell spread in a room quickly?

5. MCQs (20 Questions)


1. Matter is anything that has:

A. Mass and occupies space

B. Colour

C. Taste

D. Shape

✅ Answer: A

2. Which state of matter has definite shape and volume?

A. Gas

B. Liquid

C. Solid

D. Plasma

✅ Answer: C

3. Particles are closest in:

A. Gas

B. Liquid

C. Solid

D. All equal

✅ Answer: C

4. Liquids have:

A. Fixed shape

B. Fixed volume

C. No volume

D. No mass

✅ Answer: B

5. Gas particles move:

A. Slowly

B. Randomly and very fast

C. Not at all

D. In straight lines only

✅ Answer: B

6. Change of solid into liquid is called:

A. Freezing

B. Melting

C. Condensation

D. Sublimation

✅ Answer: B

7. Change of liquid into gas is called:

A. Evaporation

B. Freezing

C. Melting

D. Sublimation

✅ Answer: A

8. Which process changes gas to liquid?

A. Condensation

B. Melting

C. Freezing

D. Sublimation

✅ Answer: A

9. Diffusion is fastest in:

A. Solids

B. Liquids

C. Gases

D. All equal

✅ Answer: C

10. Intermolecular force is strongest in:

A. Gas

B. Liquid

C. Solid

D. Plasma

✅ Answer: C

11. Which of these is a liquid?

A. Air

B. Water

C. Stone

D. Ice

✅ Answer: B

12. Which state has maximum kinetic energy?

A. Solid

B. Liquid

C. Gas

D. All same

✅ Answer: C

13. Change of liquid into solid is called:

A. Freezing

B. Melting

C. Evaporation

D. Condensation

✅ Answer: A

14. Example of sublimation is:

A. Ice

B. Water

C. Camphor

D. Milk

✅ Answer: C

15. Gas particles have:

A. Very small spaces

B. Large spaces

C. No spaces

D. Fixed position

✅ Answer: B

16. Which state flows easily?

A. Solid

B. Liquid

C. Gas

D. Both B and C

✅ Answer: D

17. Evaporation causes:

A. Cooling

B. Heating

C. No change

D. Burning

✅ Answer: A

18. Particles of matter are:

A. Stationary

B. Always moving

C. Invisible only

D. Fixed

✅ Answer: B

19. Which state has highest compressibility?

A. Solid

B. Liquid

C. Gas

D. All same

✅ Answer: C

20. Air is a:

A. Solid

B. Liquid

C. Gas

D. Plasma

✅ Answer: C

Case-Based Questions: States of Matter (CBSE Pattern)


Case Study 1: Diffusion of Gases


Riya entered a room where someone had just sprayed perfume. Within a few seconds, the fragrance spread throughout the room. This happens because gas particles move randomly and mix with air.


Questions


1. The spreading of perfume smell in air is called:

A. Evaporation

B. Diffusion

C. Condensation

D. Sublimation


Answer: B

2. Diffusion happens fastest in:

A. Solids

B. Liquids

C. Gases

D. All equally


Answer: C

3. Why does the smell of perfume spread quickly?

Answer: Gas particles move very fast and have large spaces between them, allowing them to mix easily with air.

4. What property of gases is shown in this example?

Answer: High diffusion rate and random motion of particles.

Case Study 2: Evaporation


On a hot summer day, Rahul noticed that wet clothes dry faster when they are spread under the sun and wind.


Questions


1. The drying of clothes occurs due to:

A. Freezing

B. Condensation

C. Evaporation

D. Sublimation


Answer: C

2. Which factor increases evaporation?

A. Low temperature

B. High humidity

C. Wind speed

D. Small surface area


Answer: C

3. Why do clothes dry faster on a windy day?

Answer: Wind removes water vapour from the surface of the clothes, increasing the rate of evaporation.

4. Name two factors affecting evaporation.

Answer:

  • Temperature

  • Surface area

  • Wind speed

  • Humidity

Case Study 3: Change of State


Ice is heated in a container. After some time, it changes into water and later starts boiling to form water vapour.


Questions


1. Change of ice into water is called:

A. Freezing

B. Melting

C. Condensation

D. Sublimation


Answer: B

2. Change of water into vapour is called:

A. Evaporation / Boiling

B. Freezing

C. Melting

D. Sublimation


Answer: A

3. At what temperature does water boil at normal pressure?

Answer: 100°C

4. Why does temperature remain constant during melting?

Answer: The heat energy is used to break intermolecular forces between particles instead of increasing temperature.

Case Study 4: Properties of Matter


Solids have a definite shape and volume, liquids have a definite volume but no fixed shape, and gases have neither definite shape nor volume.


Questions


1. Which state of matter has fixed shape and volume?

A. Solid

B. Liquid

C. Gas

D. Plasma


Answer: A

2. Which state takes the shape of its container?

A. Solid

B. Liquid

C. Gas

D. Both B and C


Answer: D

3. Why are gases highly compressible?

Answer: Because gas particles have large spaces between them.

4. Give one example of each state of matter.

  • Solid – Ice / Wood

  • Liquid – Water / Oil

  • Gas – Air / Oxygen