Class 9 Practice Level 2 – Set 2 – Matter in Our Surrounding

Total questions: 25

Which of the following processes involves a decrease in energy?

Topic: Changes of State

Melting

Sublimation

Condensation

Evaporation

None

What happens to the particles of water when it freezes into ice?

Topic: Freezing and Melting

They move faster and spread apart

They lose energy and move closer together

They gain energy and spread apart

They remain the same

None

Why does the temperature of water remain constant during boiling?

Topic: Latent Heat

Because the energy is used to increase the temperature of water

Because the energy is used to overcome intermolecular forces

Because the energy is released into the surroundings

Because the water molecules stop moving

None

Why are gases compressible while liquids are not?

Topic: Properties of Gases

Because gas particles are close together

Because gas particles are far apart

Because liquid particles are far apart

Because liquid particles are in constant motion

None

Which of the following processes is endothermic?

Topic: Phase Transitions

Freezing

Condensation

Evaporation

Deposition

None

According to the kinetic theory of matter, what is the relationship between temperature and the kinetic energy of particles?

Topic: Kinetic Theory of Matter

They are inversely proportional

They are directly proportional

They are unrelated

They are equal

None

At what temperature does water have its maximum density?

Topic: Anomalous Expansion of Water

0°C

4°C

100°C

25°C

None

What is the SI unit of temperature?

Topic: Heat and Temperature

Celsius

Fahrenheit

Kelvin

Joule

None

During which phase change does a substance release energy?

Topic: Phase Transitions

Melting

Sublimation

Condensation

Evaporation

None

10.

Why are gases highly compressible?

Topic: Compressibility of Gases

Because of strong intermolecular forces

Because of weak intermolecular forces

Because of the large spaces between particles

Because of the small size of particles

None

11.

Which of the following processes result in decrease in energy of the system?

Topic: States of Matter

Condensation

Evaporation

Freezing

Sublimation

None

12.

Which of the following processes requires latent heat of fusion?

Topic: Latent Heat

Boiling of water

Freezing of water

Evaporation of water

Condensation of water vapor

None

13.

How does the rate of evaporation change with an increase in surface area?

Topic: Evaporation and Boiling

It increases

It decreases

It remains the same

It fluctuates

None

14.

Which state of matter has particles with the highest kinetic energy?

Topic: Kinetic Energy in States of Matter

Solid

Liquid

Gas

Plasma

None

15.

Which of the following factors does NOT affect the melting point of a substance?

Topic: Melting Point

Pressure

Impurities

Volume of the substance

Intermolecular forces

None

16.

What is the term for the process where a gas changes directly into a solid?

Topic: Phase Transitions

Freezing

Condensation

Deposition

Sublimation

None

17.

What happens to the volume of a gas when it is heated at constant pressure?

Topic: Thermal Expansion

It decreases

It remains the same

It increases

It fluctuates

None

18.

Why does water boil at a lower temperature on a mountain top than at sea level?

Topic: Boiling Point

Because the atmospheric pressure is lower on the mountain top

Because the atmospheric pressure is higher on the mountain top

Because the temperature is higher on the mountain top

Because the altitude is lower on the mountain top

None

19.

Which of the following best describes latent heat of vaporization?

Topic: Latent Heat of Vaporization

The heat energy required to change a liquid into a gas at its boiling point

The heat energy required to change a solid into a liquid at its melting point

The heat energy required to change a gas into a liquid at its condensation point

The heat energy required to increase the temperature of a liquid by 1°C

None

20.

Which of the following factors does NOT affect the rate of diffusion?

Topic: Diffusion

Temperature

Size of particles

Concentration gradient

Colour of particles

None

21.

What is the main difference between boiling and evaporation?

Topic: Boiling and Evaporation

Boiling occurs only at the surface; evaporation occurs throughout the liquid

Evaporation occurs only at the surface; boiling occurs throughout the liquid

Both occur only at the surface

Both occur throughout the liquid

None

22.

Why are gases more compressible than liquids?

Topic: Compressibility

Because gas particles are closely packed together

Because gas particles are far apart

Because gas particles are larger

Because gas particles move more slowly

None

23.

In a phase diagram, what does the triple point represent?

Topic: Phase Diagrams

The temperature and pressure at which a solid and liquid are in equilibrium

The temperature and pressure at which all three phases (solid, liquid, gas) coexist

The temperature and pressure at which a liquid and gas are in equilibrium

The temperature and pressure at which a solid and gas are in equilibrium

None

24.

Why do solids have a definite shape?

Topic: Properties of Solids

Because of weak intermolecular forces

Because of strong intermolecular forces

Because particles move freely

Because particles are far apart

None

25.

What is the term for the process of changing from a liquid to a gas below the boiling point?

Topic: Changes of State

Sublimation

Condensation

Evaporation

Freezing

None

1 out of 25

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Class 9 Practice Level 2 – Set 2 – Matter in Our Surrounding

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