Question

give reason for the following 1. napthalen balls disappear with some time without leaving any solids 2.we can get smell of perfume sitting several meters away

Answer 1

Answer:

1. By the process of sublimation it directly gets converted into the gaseous form.

2. Because the force of attraction between the particles of perfume is very less so the move freely

Answer 2

1. Naphthalene ball get disappeared if kept in contact with air through the process of sublimation.

Sublimation-It is the process in which a solid changes its state directly to a gas in form of vapours.

2. We are able to get the smell of perfume from several metres away because of the process of diffusion.

Diffusion-It is the process of intermixing of two particles with each other due to the motion of particles.

E.g.- In this case the moving particles of perfume are mixing with the particles present in the air and the particles of air are also moving. That moving particles bring the smell of perfume(which contains the particles of perfume) towards us and we are able to smell it even from a distance.

Hope it supports your question...........