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

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

Image of Osmosis