Free Matter in Our Surroundings 03 Practice Test - 9th Grade 

Question 1

More is the space between the particles of the matter; more is the force of attraction between them.

A. True
B. False

SOLUTION

Solution : B

In the solid state of matter, the particles are much closer to each other and the force of attraction is more between the molecules. Whereas, in a gaseous state of matter, the particles have large space between them and the force of attraction is much lesser when compared to solids and liquids.

Question 2

The container shown below has 9 particles inside it. Each particle has a mass of 3 units. The volume of the container is 27 units.
Calculate the density of the container (assume the box has no air in it).

A.

1 unit

B.

3 units

C.

9 units

D.

27 units

SOLUTION

Solution : A

The formula to find density is as follows:
Density=massvolume
The mass of the entire matter inside the given container = 3×9=27 units.
The volume of the given container is 27 units.
Now, density of the container = massvolume = 2727 = 1 unit.

Question 3

Which of the following statements are correct?

A. Solids have definite shape and volume.
B. Liquids do not have a definite shape but have a definite volume.
C. Solids do not have a definite shape but have a definite volume.
D. Liquids have definite shape and volume.

SOLUTION

Solution : A and B

Solids have a tendency to maintain their shape even when an external force is applied. So they have definite shape and volume.
Liquids have a definite volume, but no definite shape. They take the shape of the container.

Question 4

Latent heat of fusion is the heat energy that is absorbed by the solid without showing any rise in the temperature.

A. True
B. False

SOLUTION

Solution : A

Latent heat of fusion is the heat energy that is absorbed by solid without showing any rise in temperature during phase change at melting point. Since this energy is used for overcoming the inter-particle force of attraction, the kinetic energy of the particles remains constant and hence there is no rise in temperature.

Question 5

The difference in various states of matter is due to the difference in the distances between their constituent particles.

A.

True

B.

False

SOLUTION

Solution : A

Matter is made up of particles. As the distances between the particles increases, the substance becomes less dense and physical state changes.
Solids, liquids, and gases are three major physical states of matter. Following is the order of distance between particles of different states of matter. 
Gases > Liquids > Solids.

Question 6

Which of the following can transform matter from one state to another?

A. Change in temperature
B. Change in concentration
C. Change in pressure
D. Change in kinetic energy

SOLUTION

Solution : A, C, and D

Particles in solids have lesser kinetic energy when compared to liquids and gases. As temperature increases, the state changes from solids to liquids and then to gases. 

As the pressure increases, the volume of the container decreases. As we know, in solids, particles are much closer to each other and the distance between the particles increases as we move towards the gaseous state. So, with the increase in pressure, gases can be converted to liquids and then to solids.

But, change in concentration won't transform matter from one state to another.

Question 7

Which of the following option correctly differentiates between evaporation and boiling of water?

A. Evaporation takes place only at 100C.
B. Evaporation takes place at a temperature below 100C.
C. Evaporation takes place only above 100C.
D. Both evaporation and boiling are same.

SOLUTION

Solution : B

Evaporation is the process by which a liquid is converted into vapour at any temperature below the boiling point of the liquid. It is a surface phenomenon. A common example of evaporation is drying of wet clothes.
Whereas, boiling is a bulk phenomenon occuring at a certain temperature called the boiling point. For example, water has a boiling point of 100C.

 

Question 8

Why do we feel a cold sensation if we put nail polish remover on our skin?

A.

Acetone freezes on our hand surface.

B. Acetone being volatile, evaporates rapidly and leaves a cooling sensation.
C.

Acetone starts boiling taking heat from the hand.

D.

Acetone melts on our hand.

SOLUTION

Solution : B

Evaporation causes cooling. The particles of a substance while evaporating absorbs heat energy from its surroundings and convert into vapour. Acetone has a low boiling point of 56 C. So, when we put acetone on our hand or skin, being higly volatile, it evaporates rapidly absorbing heat from the hand and leaving back a cold sensation. Therefore, we feel cold.

Question 9

The amount of water vapour present in the air is known as _______.

A. Density
B. Humidity
C. Precipitation
D. Vapourisation

SOLUTION

Solution : B

The air around us holds water in the form of vapour (gas). Humidity is the amount of water vapour present in the air. During winter, due to low temperature, the humidity in the air falls down. This is the reason why our skin becomes dry in winters.

Question 10

Which of the following states of matter has the highest kinetic energy of the particles?

A. Solids
B. Liquids
C. Gases
D. All the states have same kinetic energy

SOLUTION

Solution : C

Higher the distance between the particles, lower is the inter particle force of attraction. Hence, particles would be free to move with higher kinetic energy. 
Therefore, the order of kinetic energy: Solids < Liquids < Gases