Matter In Our Surroundings

Question 1

Define matter. Write few examples.

Answer 1

Anything which occupies space and has mass is called a matter. For example, pen, chalk, chair, water, bag, etc.

Question 2

What are the two classifications of matter on the basis of their properties?

Answer 2

Physical properties and Chemical properties

Question 3

What are the 3 classification of matter on the basis of their physical properties?

Answer 3

Solid, liquid, gas

Question 4

What are the 3 classification of matter on the basis of their chemical properties?

Answer 4

Elements, compounds and mixtures

Question 5

What are the characteristics of particles of matter?

Answer 5

1)Particles of matter have spaces b/w them.
2)Particles of matter attract each other.
3)Particles of matter are in the state of continuos motion
4)Particles of matter have tendency to diffuse.
5) Particles of matter are very very small

Question 6

Define diffusion.

Answer 6

It is the process of intermixing of particles of two different types on their own.

Question 7

The smell of hot sizzling food reaches us several meters away but to get the smell of cold food we need to go close. Give reason

Answer 7

Particles of matter continuously moving thus they posses kinetic energy. As the temperature rises the rate of diffusion also increases and the particles that carry the smell of hot sizzling food mix with the particles of air and reaches us several meters away but to get the smell of cold food we have to go close as in comparison the particles that carry the smell of cold food diffuse slower than that of hot food.

Question 8

What are the properties of solids?

Answer 8

1) Solids have fixed shape and volume
2) Solids have high density
3) Solids do not flow
4) Solids cannot be compressed much
5) Solids do not fill the container completely

Question 9

What are the properties of gases?

Answer 9

1) Gases have neither fixed shape nor fixed volume
2) Gases have low density
3) Gases flow easily
4) Gases can be compressed much
5) Gases can fill a container completely

Question 10

What are the properties of liquids?

Answer 10

1) Liquid do not have a fixed shape but a fixed volume.
2) Liquids have low to moderate density.
3) Liquids can flow
4) Liquids cannot be compressed much
5) Liquids cannot fill the container completely

Question 11

Sponge is solid but it can be compressed. Give reason.

Answer 11

Sponge contains a large number of minute holes in it which are filled with air when we press the sponge air is expelled from its holes making it highly compressible.

Question 12

Which is the main content of natural gas?

Answer 12

Methane (CH4)

Question 13

Which is the main content of LPG?

Answer 13

Butane (C4H10)

Question 14

Name the substance which is added to LPG to detect the leakage.

Answer 14

Ethyl mercaptan (C2H5SH)

Question 15

How to convert Celsius into Kelvin?

Answer 15

273+ Temperature in Celsius

Question 16

How to convert Kelvin into Celsius?

Answer 16

Temperature in Kelvin - 273

Question 17

Define Melting (fusion)?

Answer 17

The process of conversion of solid state to liquid state at specified conditions of temperature and pressure.

Question 18

What is a melting point?

Answer 18

A definite temperature at which solid starts melting.

Question 19

Define boiling.

Answer 19

The process of conversion of liquid state to gaseous state at specified conditions of temperature and pressure

Question 20

What is boiling point?

Answer 20

A definite temperature at which liquid starts to convert into gas

Question 21

Define condensation.

Answer 21

The process of conversion of matter from its gaseous state to liquid state at specified conditions of temperature and pressure.

Question 22

Define freezing.

Answer 22

The process of conversion of liquid state to solid state at specified conditions of temperature and pressure.

Question 23

Define sublimation.

Answer 23

The process of conversion of matter from its solid state to gaseous state without passing through liquid state on heating.

Question 24

Define deposition.

Answer 24

The process of conversion of matter from its gaseous state to solid state without passing through liquid state

Question 25

Define latent heat.

Answer 25

The heat energy required to convert the state of matter without rising its temperature.

Question 26

Define latent heat of fusion.

Answer 26

The heat energy required to convert 1kg of solid into liquid at its atmospheric pressure and at its melting point without rising its temperature.

Question 27

Define latent heat of vapourisation.

Answer 27

The amount of heat energy required to convert qkg of liquid into gas without rising its temperature

Question 28

Ice at 0°C is more effective in cooling than water at 0°C. Give reason.

Answer 28

This is due to the fact that for melting each kilogram of ice takes the latent heat from the substance and hence, cools the substance more effectively, On the other hand water at 0°C cannot take any such letest heat from the substance.

Question 29

Exlain why steam at 100°C causes to more severe burns than water at 100°C.

Answer 29

This is due to the fact that steam contains more latent heat in the form of latent of vapourisation than boiling water So steam produces more severe burns.

Question 30

When we put Spirit at the back of our hand. Our hand gets cooled. Give reason.

Answer 30

This is due to the fact that Spirit needs latent heat of vapourisation to change its state from liquid to gas. It takes this heat from our hand so our hand loses heat and gets cooled.

Question 31

During the supply of latest heat no change in temperature takes place. Give reason

Answer 31

The latent heat which we supply is used to break down the intermolucular force of attraction between the particles to change the state of matter. The laten heat does not increases the kinetic energy of the particles of substance. Hence, there is no change in the temperature during the change of states of matter

Question 32

Define evaporation.

Answer 32

The process of conversion of liquid into vapours at any temperature below its boiling point.

Question 33

What are the factors on which the rate of evaporation depends?

Answer 33

1)The rate of evaporation is directly proportional to the surface area.
2)The rate of evaporation is directly proportional to the temperature.
3)The rate of evaporation is directly proportional to wind speed.
4) the rate of evaporation is inversely proportional to humidity.

Question 34

What are the differences between boiling and evaporation?

Answer 34

Boiling
1) It is the process of conversion of liquid into vapours at a specified condition of temperature and pressure
2) It is a bulk phenomena.
3) It produces heating effect.
Evaporation
1) It is a process of conversion of liquid into vapours at any temperature below its boiling point.
2) It is a surface phenomena.
3) It produces cooling effect.

Question 35

How does the water taken in an earthen pot becomes cold during summer?

Answer 35

The earthen pot has large number of minute pores in its wall. Some of the water keeps seeping out through these pores to the outside of the pot, this water evaporate continuously and takes latent heat from the pores and the remaining water and in this way the remaining water loses heat and gets cooled.

Question 36

What type of clothes should we wear in summer and why?

Answer 36

We should wear cotton clothes in summer because cotton is a good absorber of water, so it absorbs the sweat from our body and exposes it to air for evaporation and it evaporates by taking latent heat from our body, hence our body loses heat and gets cooled.

Question 37

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

Answer 37

A desert cooler cools better on a hot and dry day because the higher temperature on a hot day increases the rate of evaporation of water and the dryness also increases the rate of evaporation of water and due to the increased rate of evaporation of water a desert cooler cools better on a hot and dry day.

Question 38

Why are we able to sip hot tea faster from a saucer than from a cup?

Answer 38

Saucer has large surface area due to which the evaporation of hot tea from the saucer is faster and this faster evaporation cool the tea quickly making it more convenient for us to drink it.