9. Give reason : A gas fills completely the vessel, in which it is kept.
10. A gas exerts pressure on the of container Why?
U. A table is called as solid Why?
12. We can easily move our hand in air. But to do the same through a
solid block of wood, we need karate expert. Why?
13. The diver is able to cut through water in swimming pool. Why?
14. Naphthalene balls disappear with time without leaving any solids.
Why?
15. Why cannot you smell the perfume at a short distance when expense
stick is not lighted?
16. Define Brownian movement
17. Differentiate Force of Adhesion and Force of Cohesion /
Answers
9.There is little attraction between particles of gas. Thus, gas particles move freely in all directions. Therefore, gas completely fills the vessel in which it is kept.
10.The gas particles are in random motion due to weak intermolecular force of attraction. These gaseous molecules continuously collide among themselves and they hit the walls of the container with a greater force.
Therefore, gas exerts pressure on the walls of the container.
12.Particles of air have large spaces between them. On the other hand, wood has little space between its particles. Also, it is rigid. For this reason, we can easily move our hands in air, but to do the same through a solid block of wood, we need a karate expert.
11.A wooden table has a definite shape and volume. It is very rigid and cannot be compressed i.e., it has the characteristics of a solid. Hence, a wooden table should be called a solid.