Question

Exercises
. Convert the following temperatures to the celsius scale.
(a) 293 K
(b) 470 K.
Convert the following temperatures to the kelvin scale
(a) 25°C
(b) 373°C.
Give reason for the following observations.
(a) Naphthalene balls disappear with time without
any solid.
(b) We can get the smell of perfume sitting several
away
Arrange the following substances in increasing order o
of attraction between the particles, water, sugar, oxyg​

Answer 1

Answer:

(a)20°c

(b)197°c

(a)247°c

(b)646°c

(a)

(b) due to diffusion

sugar,water, oxygen

Answer 2

Answer:

• 19.85
• 196.85

1. 298.15K
2. 646.15

Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid.

We can get the smell of perfume sitting several metres away. Perfume has a higher degree of vaporization and its vapour diffuse into the air easily. Gaseous particles possess high speed and move very rapidly in all directions. .This enables us to smell the perfume from a distance.

The forces of attraction are the strongest in solids, followed by liquids and the weakest in gases. Oxygen is a gas, water is a liquid and sugar is a crystalline solid. So the increasing order of forces of attraction is Oxygen < Water < Sugar.