Give reasons
(i) A gas fills completely the vessel in which it is
kept.
(ii) A gas exerts pressure on the walls of the
container.
(iii) A wooden table should be called a solid.
(iv) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert
Answers
Answer:-
(i ) In gases, the particles are very loosely packed and the attractive forces between the particles are negligibly small. As a result, the particles of gases, move randomly in all directions and
therefore, fill the vessels completely.
(ii) The molecules of a gas are free to move randomly in all directions. During their motion, they collide with one another and also with the walls of the container. The constant bombartment of the molecules on the walls of the container exerts a steady force. The force acting per unit area on the walls of the container is called pressure. Thus, gases exert pressure.
(iii) A wooden table is called a solid because it has a definite mass, volume and shape.
(iv) In air, there is lot of empty space between the molecules and the forces between the particles are almost negligible. Hence we can move our
hand in air. However, we cannot move our hand in a solid block because there are strong forces of attractions between particles in a solid and there is no empty space between them.
(a) The particles of gases have low force of attraction between them. The particles are freely moving in the vessel in which it is filled.
(b) The particles of gas has least force of attraction. They are constantly moving randomly. The particle of gas hit the walls of container thereby applying force and hence pressure on the wall.
(c) Wooden table has a definite shape and the definite volume. The particles of wood are closely packed. They do not take the shape of the container. Hence wooden table satisfies the properties of solid.
(d) The particles of air are very loosely bounded. They are far away from each other having a lot of space between them. Hence we can easily move our hands in air. But in a solid block, the particles are tightly held by a strong force of attraction. So there is some or no space between them. Hence we need a karate expert.