Mater In Our Surroundings | Class 9 Science NCERT Chapter 1 Question and Answer |

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

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  1. 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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  1. (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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  1. 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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  1. 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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  1. What is the physical state of water at:

a. 250ºC b. 100ºC

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

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

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

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

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  1. 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

  1. Convert the following temperatures to the kelvin scale.

(a) 25° C (b) 373° C

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

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  1. What is the physical state of water at-

(a) 25ºC (b) 0ºC (c) 100ºC

(ক) 25ºC (খ) 0ºC (গ) 100ºC

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

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

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

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