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1.1 Choose the correct Answer.
Time: 7 Minutes
Total Marks: 8
1.
Matter in this world exists in _____ states.
(a) two
(b) three
(c) four
(d) five
2.
The average kinetic energy of the particles is directly proportional to:
(a) pressure
(b) volume
(c) temperature
(d) concentration
3.
When a solid is heated, its particles initially start:
(a) moving freely
(b) vibrating with higher frequency
(c) rotating in fixed positions
(d) translating randomly
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4.
Heating a solid below its melting point increases its:
(a) density
(b) kinetic energy and temperature
(c) mass
(d) volume
5.
The process of conversion of gas into liquid at constant temperature is called:
(a) Evaporation
(b) Freezing
(c) Condensation
(d) Sublimation
6.
Ammonia gas can be liquefied at:
(a) 25°C
(b) 34°C
(c) -25°C
(d) -34°C
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7.
The direct conversion of a solid into vapours without melting is called:
(a) evaporation
(b) condensation
(c) sublimation
(d) melting
8.
Formation of Frost in winter season is an example of:
(a) Boiling
(b) Freezing
(c) Evaporation
(d) Deposition
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Total Marks: 17
(Subjective Type)
Time: 33 Minutes
2. Write short answers to any six (6) questions.
[6 × 2 = 12]
(i)
How kinetic particle theory for gases was formulated?
(ii)
What is meant by the melting point of a solid?
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(iii)
What does the horizontal part of a heating curve represent?
(iv)
Write some uses of phase change materials.
(v)
Why does boiling occur throughout the liquid while evaporation occurs only at the surface?
(vi)
What is sublimation? Give an example.
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(vii)
What is deposition? Give an example.
(viii)
Why do we feel comfortable wearing cotton clothes in summer?
(ix)
What changes occur in the particles of a solid at its melting point?
Note: Attempt any one question.
[5 × 1 = 5]
3.
Explain kinetic particle theory of matter.
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4.
Explain melting. How a solid is converted into liquid?
