Fill in the blanks:
(a) Evaporation of a liquid at room temperature leads to a——— effect.
(b) At room temperature the forces of attraction between the particles of
solid substances are———than those which exist in the gaseous state.
(c) The arrangement of particles is less ordered in the ——— state. However,
there is no order in the ——— state.
(d) ——— is the change of gaseous state directly to solid state without
going through the ———state.
(e) The phenomenon of change of a liquid into the gaseous state at any
temperature below its boiling point is called———.
NCERT Class IX
Sciences - Exemplar Problems
Chapter 1. Matter in our Surroundings
Answers
b) Stronger than those..
c) liquid state.... gaseous state
d) deposition is the ..... liquid state
e) evaporation..
Explanation:
When evaporation occurs then heat is absorbed by the surrounding causing a decrease in the temperature of surrounding molecules. As a result, cooling effect arises.
In solids, molecules are held together by strong intermolecular forces of attraction. Therefore, they have fixed shape and volume. Whereas liquid molecules are held together by less strong forces so they are able to slide past each other. Hence, they do not have fixed shape and volume.
When there occurs decrease in the volume of a liquid below its boiling point then this phenomenon is known as evaporation.
When a solid changes directly into gaseous state without under going liquid state or vice versa then this process is known as sublimation.
Therefore, blanks are filled as follows.
(a) Evaporation of a liquid at room temperature leads to a cooling effect.
(b) At room temperature the forces of attraction between the particles of
solid substances are stronger than those which exist in the gaseous state.
(c) The arrangement of particles is less ordered in the liquid state. However,
there is no order in the gaseous state.
(d) Sublimation is the change of gaseous state directly to solid state without
going through the liquid state.
(e) The phenomenon of change of a liquid into the gaseous state at any
temperature below its boiling point is called evaporation.