10. Answer the following questions:
(a) What happens to the particles of matter when heat energy is supplied?
(b)Why does the fragrance of a perfume spread all over in a room on spraying?
(c)Why do we say that evaporation is a surface phenomenon?
(d)Why gases are more compressible as compared to solids?
(e) What is a dry ice and what are its properties?
Answers
Answer:
a)When solid is heated,the particles are given more energy and start to vibrate faster. At a certain temperature ,the particles vibrate so much that their ordered structure breaks down . At this point the solid melts into liquid
b)Perfume will diffuse into the air with the alcohol they contain. the molecules of perfume are in gaseous stateand mixing with the molecules of air in the room. Because the motion of the molecules is entirely random , the probablity of finding a given volume of air approaches an even distribution throughout the roon as time goes on.
c)Evapouration is surface phenomenon as if the surface area is increased , the rate of evaporation is increased.
d)Molecules of gas are far apart they bounce off of each other and dont stick together,so there is lot of space between them.when they are squished closer together it just means that the run into each othet a little more often. that makes it possible to compress.On the other hand solids have molecules that are already stuck together
e)Dry ice is the solid form of cabon dioxide .
properties:
Dry ice is colourless,non-flammable with a sour zesty odor , and can lower the pH
of a solution when dissolved in water forming carbonic acid
Answer:
What happens to the particles of matter when heat energy is supplied?
⇒ When heat energy is supplied to the particles of matter they start vibrating because it indicates the force with which a particle moves.
Why does the fragrance of a perfume spread all over in a room on spraying?
⇒ The fragrance of a perfume spread all over in a room on spraying because the particles get diffuse in the air and spread all over the room as particles are continuously moving In which particles intermix on their own.
Why do we say that evaporation is a surface phenomenon?
⇒ Evaporation is said to be surface phenomenon because it occurs in the surface. Example :- Spreading of wet clothes increase surface area and so evaporation becomes faster as a result drying of wet clothes become faster. Therefore we can say that the rate of evaporation increases with surface area.
Why gases are more compressible as compared to solids?
⇒ Gases are more compressible as compared to solid because the properties of gases are different from solid as particle of gases are not rigid, they do not have definite shape, no definite volume, Intermolecular force is minimum, Intermolecular space is maximum As a result They can be easily compressed and stored in a closed vessel.
What is a dry ice and what are its properties?
⇒ It is a solid Carbon dioxide (CO2)
Properties :-
It is solid, colorless , non flammable, odourless