NCERT Class – 9 Science solution: Chapter 1 Matter in Our Surroundings-Part 3

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Question 13

Fill in the blanks:

(a) Evaporation of a liquid at room temperature leads to a __________ effect.

(b) At room temperature the forces of attraction between the particles of solid substances are __________ than those which exist in the gaseous state.

(c) The arrangement of particles is less ordered in the __________ state. However, there is no order in the __________ state.

(d) ________ is the change of gaseous state directly to solid state without going through the _________ state.

(e) The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called__________.

Answer:

(a) Cooling

(b) Stronger

(c) Liquid, gaseous

(d) Sublimation, liquid

(e) Evaporation

Question 14

Match the physical quantities given in column A to their SI units given in column: B

SI Units
SI units

Physical quantities

SI units

A

Pressure

i

Cubic metre

B

Temperature

ii

Kilogram

C

Density

iii

Pascal

D

Mass

iv

Kelvin

E

Volume

v

Kilogram per cubic metre

Answer:

Image of what is SI unit

Image of What is SI Unit

Question 15

The non SI and SI units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:

SI and Non SI Units
SI and non SI units

Column A

Column B

A

Degree Celsius

i

Kilogram

B

Centimeter

ii

Pascal

C

Gram per centimeter cube

iii

Metre

D

Bar

iv

Kelvin

E

Milligram

v

Kilogram per metre cube

Answer:

Question 16

‘Osmosis is a special kind of diffusion’. Comment.

Answer:

  • Yes, this is true.

  • In both the phenomena, there is movement of particles from region of higher concentration to that of lower concentration.

  • However, in the case of osmosis the movement of solvent is through a semi permeable membrane which is permeable only to water molecules.

Image of Osmosis

Image of Osmosis

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