1. Matter

Question 1

what is matter

Answer 1

anything that occupies space, has mass, and can be perceived by our senses

matter means all the living and non-living things of the universe

Question 2

What did Maharishi Kannada call the tiny particles of matter

Answer 2

anu

Question 3

what did the Indian philosophers consider matter to be made up of?

Answer 3

Five tattvas

Akash, Vayu, Tejas (Agni), Jal, Prithvi

Question 4

What is matter composed of?

Answer 4

tiny particles called molecules

they exist freely in nature and have the properties of whatever substance they make up

Question 5

what are the three types of molecules?

Answer 5

Monoatomic (only one atom)

Diatomic (two atoms)

Polyatomic (more than 2 atoms)

Question 6

state the 4 characteristics of molecules

Answer 6

they are small in size

they have spaces between them

they are in constant motion as they possess kinetic energy

they attract each other

Question 7

what is the size of a molecule

Answer 7

nearly 10-10 (10 raised to minus 10)

Question 8

intermolecular space

Answer 8

space between molecules of matter is called intermolecular space

Question 9

What is the motion of molecules in solids, liquids and gases respectively

Answer 9

Solids - vibrate about their mean positions

Liquids - free to move within the boundary of the container

Gases - move in a random manner everywhere in the space available to them

Question 10

what is lycopodium powder also called?

Answer 10

jash powder

Question 11

intermolecular force of attraction

Answer 11

the molecules of matter exert a force of attraction on each other

this is called intermolecular force of attraction

Question 12

it is due to which force that intermolecular force is caused?

Answer 12

electrostatic force

Question 13

at what measure of separation does the intermolecular force of attraction vanish

Answer 13

10 raised to -9 meters

Question 14

define force of cohesion

Answer 14

the intermolecular force of attraction between the molecules of the same substance is called the force of cohesion

Question 15

define force of adhesion

Answer 15

the intermolecular force of attraction between the molecules of two different substances is called force of adhesion

Question 16

why can liquids and gases flow

Answer 16

molecular forces of attraction are weaker in them

Question 17

properties of solids

Answer 17

• rigid
• definite size (volume)
• definite shape

Question 18

properties of liquids

Answer 18

• nonrigid

definite volume

no definite shape (take the shape of the vessel in which they are placed)

Question 19

properties of gases

Answer 19

nonrigid

no definite volume

no definite shape (take both volume and shape of container)

Question 20

3 properties which decided the state of a substance

Answer 20

intermolecular space

intermolecular force of attraction

kinetic energy of molecules (due to their motion)

Question 21

when does matter exist as a solid

Answer 21

when
intermolecular force is very strong
Kinetic energy is less
intermolecular space is reduced

Question 22

when does matter exist as a liquid

Answer 22

when

Intermolecular forces are not as strong as solids.
kinetic energy is sufficient for to-and-fro motion
intermolecular space is increased

Question 23

when does matter exist as a gas

Answer 23

intermolecular force is negligible
kinetic energy is very high

Question 24

define change of state

Answer 24

The process of change from one state to another state either by absorption or rejection of heat at a constant temperature is called change of state

Question 25

what is melting also called

Answer 25

fusion

Question 26

melting

Answer 26

when a solid is heated, it changes into a liquid at a fixed temperature

Question 27

freezing

Answer 27

when a liquid is cooled, it changes into a solid at a fixed temperature

Question 28

boiling/vaporization

Answer 28

when a liquid is heated, it changes into its vapor at a fixed temperature

Question 29

condensation/liquefaction

Answer 29

when vapor is cooled at a fixed temperature, it changes into liquid state

Question 30

1 property of condensation point

Answer 30

The condensation point of a gas is the same as the boiling point of its liquid

Question 31

sublimation

Answer 31

When a solid changes directly into its vapor state without changing into a liquid

Question 32

deposition/reverse sublimation

Answer 32

when a gas is cooled, it changes directly into a solid without passing into its liquid state

Question 33

what is latent/hidden heat?

Answer 33

The quantity of heat given to or rejected by a substance does not change the temperature of that substance\ this is called latent heat

Question 34

melting point of solid

Answer 34

The temperature at which a solid changes into a liquid without further change in temperature

Question 35

1 property of melting point

Answer 35

The melting point of a solid is the same as the freezing point of its liquid state

Question 36

melting point of wax

Answer 36

55 degrees Celsius

Question 37

Explanation of the relationship between melting point and freezing point

Answer 37

The amount of heat rejected during freezing is the same as the amount of heat absorbed during melting for the same mass of the substance

Question 38

specific latent heat

Answer 38

amount of heat absorbed/rejected during change of state for a unit mass of a substance measured in joules per kilogram

Question 39

what is freezing mixture? give 1 use

Answer 39

the mixture of salt added to ice is called freezing mixture it is used to prepare kulfis

Question 40

in the process of melting and vaporization, which energy increases

Answer 40

potential energy

Question 41

boiling point of a liquid

Answer 41

temperature at which a liquid change into a vapor without further increase in temperature

Question 42

what happens to the boiling point of a liquid when impurities are added

Answer 42

it increases

Question 43

5 factors which affect the rate of evaporation

Answer 43

temperature of the surroundings area of exposed surface (surface area) Nature of liquid flow of air above the liquid presence of moisture/ humidity

Question 44

evaporation

Answer 44

liquid changes into vapor at all temperatures from the surface of the liquid

Question 45

4 applications of evaporation

Answer 45

- water gets cooled in earthen pot - doctors advise putting wet cloth on on patients having a high fever - tea is put in a saucer to cool down faster - evaporation of sweat helps maintain body temperature

Question 46

what is the average kinetic energy of molecules of a subatnces

Answer 46

measure of its temperature