Question

(a) Naphthalene balls disappear with time without leaving any
4. Arrange the following substances in increasing order of forces
3. Give reason for the following observations.
solid.
(b) We can get the smell of perfume sitting several metres away.
of attraction between the particles, water, sugar, oxygen.
5. What is the physical state of water at-
(a) 25°C
(b) 0°C
(c) 100°C ?
6. Give two reasons to justify-
(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.
7. Why is ice at 273 K more effective in cooling than water at the
same temperature?
8. What produces more severe burns, boiling water or steam?
9. Name A,B,C,D,E and F in the following diagram showing change​

Answer 1

Answer:

Explanation:

Naphthalene balls disappear with time without leaving any solid, because naphthalene balls exhibit the property of sublimation. That is, it changes from solid state to gas easily. So evaporation of naphthalene balls takes place directly to the vapour state leaving no solid.