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Answer the following.

a) Tabulate the differences in the characteristics of matter.

b) Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.

Answer :

(a) The difference in the characteristics of the three states of matter.






Fixed shape

No Fixed shape

No Fixed shape


Fixed volume

Fixed volume

No Fixed volume

Intermolecular force


Less than solids

Very less

Intermolecular space

Very less

More than solids



Rigid/cannot flow

Can flow/not rigid

Can flow/not rigid




Highly compressible

(i) Rigidity: It is the property of a substance to retain its shape when an external force acts upon it.

(ii) Compressibility: When the intermolecular space between the particles of a matter reduces due an external force, this property of the matter is known as compressibility. Gases and liquids are compressible but not solids are negligibly compressible.

(iii) Fluidity: The tendency of a particle to flow is called as fluidity. Gases and liquids can flow but not solids cannot flow as they are rigid.

(iv) Filling of a gas container: Gases have particles which vibrate in all direction randomly due to more kinetic energy than solids and liquids and hence takes the shape of container in which they are stored.

(v) Shape: It is the definite structure of an object within an external boundary. Solids have definite shape (due to high intermolecular forces) and liquids and gases takes the shape of container in which they are stored.

(vi) Kinetic energy: The energy which is possessed by the particles due to their motion is referred to as kinetic energy. Increasing order of kinetic energy in different states is as follows:
Solids < Liquids < Gases.

(vi) Density: It is defined as mass per unit volume of a substance, i.e.,   \( d = \) \( M \over V \)

where, ‘d’ is the density, ‘M’ is the mass of the substance and ‘V’ is the volume of the substance.

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