Chapter 1

Mater In Our Surroundings


Page-3

Questions-

1. Which of the following are matter?


Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.

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2. Give reasons for the following observation:

The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.

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3. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

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4. What are the characteristics of the particles of matter?

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Page-6


Questions-


1. The mass per unit volume of a substance is called density.

(denisty = mass / volume). Arrange the following in order of increasing density - air, exhaust from chimneys, honey water, chalk cotton and iron.

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2. (a) Tabulate the differences in the characteristics of states of matter.

(b) Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and denisty.

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3. Give reasons

(a) A gas fills completely the vessel in which it is kept.

(b) A gas exerts pressure on the walls of the container.

(c) A wooden table should be called a solid.

(d) We can easily move our hand in air but to do the same through a solid black of wood we need a karate expert.

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4. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.

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Page-9


Questions-


1. convert the following temperature to celsius scale.

a. 300k    b. 573k.

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2. What is the physical state of water at:

a. 250ºC     b. 100ºC

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3. For any substance. why does the temperature remain constant during the change of state?

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4. Suggest a method to liquefy atmospheric gasses.

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Page-10

Questions-

1. Why does a desert cooler cool better on  a hot dry day?


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2. How does the water kept in an earthen pot (matka) become cool during summer?


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3. Why does our palm feel cold when we put some acetone or petrol or perfume on it?

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4. Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

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5. What type of clothes should we wear in summer?


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Page-12

Exercises-


1. Convert the following temperatures to the celsius scale.

(a) 293 K                         (b) 470 K

2. Convert the following temperatures to the kelvin scale.

(a) 25° C                         (b) 373° C


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.

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4. Arrange the following substances in increasing order of forces of attraction between the particles- Water, Sugar, Oxygen.

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5. What is the physical state of water at-

(a) 25ºC        (b) 0ºC         (c) 100ºC

(ক) 25ºC (খ) 0ºC (গ) 100ºC

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6. Give two reasons to justify-

(a) Water at room temperature is liquid.

(b) an iron almirah is a solid at room temperature.


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7. Why is ice at 273 k more effective in cooling than water or steam?

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8. What produces more severe burns, boiling water or steam?


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9. Name A, B, C, D, E And F in the following diagram showing change in its state



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Question Type By- Punya Hazarika & Himashree Bora.



Post ID: DABP001877