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=Question 1, 2

=Question 3, 4

=Question 5,6,7

=Question 8, 9

 

Question 3. Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
Question 4. Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.

Question 3. Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
Answer:
(a) Naphthalene balls undergo sublimation due to which it converts directly into vapours and disappear into air without leaving any solid.
(b) The particles of perfume diffuse rapidly into the air and its smell can be felt while sitting several metres away.

Question 4. Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.
Answer: The force of attraction between the particles increases as we go from liquid to gas so the required order is: Oxygen<water<sugar.



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Question 3. Give reason for the following observations. (a) Naphthalene balls d

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