question_answer

   (a) Tabulate the differences in the characteristics of the three states of matter. (b) Comment on the following: Rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.                                  [NCERT]

Answer:

               (a)

Solids	Liquids	Gases
1. Particles are closely packed.	1. Particles are loosely packed.	1. Particles are at a sufficient distance apart.
2. Attraction forces are highest.	2. Attraction forces are less than of solids.	2. Attraction forces are minimum.
3. They possess definite shape, mass and volume.	3. They do not possess definite shape but possess definite mass and volume.	3. They possess neither definite shape nor definite volume, but possess definite mass.
4. The particles are fixed and possess the least energy.	4. Particles are free to move and have higher energies than that of solids.	4. The particles have maximum freedom of motion and possess maximum energies.
5. They have least compressibility.	5. They have higher compressibility than solids.	5. They have the highest compressibility.
6. They possess the highest density.	6. They possess lower density than that of solids.	6. They possess least density.

  (b) (i) Rigidity: It is the property of the solids to maintain shape against external force. (ii) Compressibility: It is the property of gases. On applying high pressure, the volume of the gas decreases. (iii) Fluidity: It is the property of liquids and gases by which they have a tendency to flow. (iv) Filling a gas container: When a denser gas is transferred into another empty container, it spreads and occupies the whole volume of the empty container replacing the air. (v) Shape: It is the property of solids. Outer surfaces of a solid form a certain shape. (vi) Kinetic energy: The constituent particles of a matter are not stationary. They are found in constant motion. The particles of gases have maximum kinetic energy because their particles move at high speed. Kinetic energy = , where 'm' is the mass of the particle and 'v' the velocity of the particle. (vii) Density: It is the property of a matter. It is defined as the mass per unit volume, i.e., Density =