Give reasons: Gas fills completely the vessel

(a) A gas fills completely the vessel in which it is kept: Gas particles have high kinetic energy and move randomly, spreading out to fill all available space.

(b) A gas exerts pressure on the walls of the container: Gas molecules are in constant motion and collide with the walls of the container, exerting pressure.

(c) A wooden table should be called a solid: Wood has a definite shape and volume, and its particles are closely packed together, giving it rigidity and resistance to deformation.

(d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert: Air particles are widely spaced and easily displaced, whereas the particles in a solid block of wood are tightly packed, making it difficult to move through without breaking the bonds between particles.