Question

(A): How naphthalene balls kept in stored clothes in our homes disappear over a period of time?

(B): Name the terms for the following :​
(i) The change of a solid into liquid
(ii) The force of attraction between the molecules of matter.​
(iii) The particles of matter which may or may not have independent existence.​

Answer 1

(A): Naphthalene or mothballs kept between clothes disappear over a period of time because naphthalene balls undergo sublimation and form naphthalene vapours, which disappear into the air.
On sublimation, the kinetic energy of particles increases, and the interparticle attraction decreases. Thus, they enter directly into their gaseous state.

(B):
(i)The change of a solid into liquid​- Melting​

(ii)​The force of attraction between the molecules of matter ​ – Intermolecular force of attraction​

​(iii)The particles of matter which may or may not have independent existence.​ - Solid