Complete, in detail, information about chapter 1 of class 9 CBSE board.

2. What is Matter?
• Everything in the universe is made up of material which
scientists have named MATTER.
• Everything which occupy mass and have space is called
MATTER.
• Ex.., the air we breathe, the food we eat, stones,
clouds, stars, plants and animals, even a small drop of
water or a particle of sand- everything is matter.
• Early Indian philosophers classified matter in the form
of five basic elements- the “Panch Tatva”- air, earth,
fire, sky and water.
• Modern day scientists have evolved two types of
classification of matter based on their physical
properties and chemical nature.

3. Classification of MATTER
• On the basis of physical properties, matter can be classified as Solid,
Liquid and Gas.
• On the basis of chemical nature, matter can be classified as pure
substance and mixture.
• Pure substance may be element or compound.
• Mixture can be homogeneous and heterogeneous.

4. Physical nature of matter
• 1. Matter is made up of particles. 2. How small are these particles of matter?

5. Characteristics of particles of matter
• According to kinetic theory,
1. Particles of matter have spaces between them
interparticle space
2. Particles of matter are continuously moving
kinetic energy, diffusion
3. Particles of matter attract each other
force of attraction
Temperature Diffusion
Temperature Kinetic energy
ex. KMnO4 in cold and hot water.

6. States of matter
• Matter around us exist in three states…
• Solid----Iron, wood, stone, sand, pencil, book, gold, ice etc…
• Liquid----water, milk, petrol, alcohol, oil, juice, cold drink etc…
• Gas----Air, oxygen, helium, nitrogen, CNG, LPG, carbon dioxide etc…

7. Packing of particles and force of
attraction
• Force of attraction
• Interparticle Space
• Rigidity
• Density
• Lattice

8. Definitions
•Solid- is defined as that form of matter
which possesses rigidity, is incompressible
and hence has a definite shape and a definite
volume.
•Liquid- is defined as that form of matter
which possesses fluidity but is almost
incompressible and hence has a definite
volume but no definite shape.
•Gas- is defined as that form of matter which
possesses fluidity but is highly compressible
and hence has neither definite shape nor
definite volume.

9. Properties of Solid State
1. Have definite shape and distinct boundaries
2. Possess rigidity
3. Have Definite volume
4. Not possess diffusion
5. Not compressible
Time to think ?????
1. What about Rubber Band?
2. What about Sugar and salt?
3. What about a Sponge?

10. Properties of Liquid State
• No fixed Shape
• Have definite volume
• Possess fluidity
• Not rigid
• Shows diffusion
• Interparticle space- more compare to solid
• Least compressible
Time to think?
why ice float on water though it has higher
density than water?

11. Types of diffusion in Liquid
1. Solid into liquid
2. Liquid into liquid
3. Gases into liquid
Rate of diffusion
it increase with the temperature

12. Properties of Gaseous State
• No definite shape
• No definite volume (volume of gas is equal
to volume of container)
• Maximum fluidity
• Least rigidity
• Highly compressible (CNG, LPG)
• Low density
• High kinetic energy
• Exert pressure (ex.. balloon)
• Diffuse rapidly

13. Diffusion in gases

14. Other states of matter
•Plasma is super energetic and super exited
particle in form of ionized gases.
• Ex. Neon bulb(Ne), Fluorescent tube (He)
The sun and the stars glow due to presence of plasma.

15. • Bose-Einstein Condensate
In 1920, Indian physicist Satyendra Nath Bose done
some calculations on the fifth state of matter. Based on these
calculations, Albert Einstein predicted a new state of matter
called Bose-Einstein Condensate. (BEC)
BEC formed when a gas having very low density is cooled
to super low temperature.

16. Quick
Revision

17. SCALE OF MEASURING TEMPERATURE
• Celsius Scale
0 ˚C to 100 ˚C
• Fahrenheit scale
˚F=9/5(˚C)+32
• Kelvin Scale
K=273 + ˚C
Solve for this…..
1. Convert 55 ˚C to Kelvin.
2. Convert -176 ˚C to Kelvin.
3. Convert 255 K to ˚C
4. Convert 20 K to ˚C

18. Can Matter Change its State?
• Water can exist in three states of matter–
• solid, as ice,
• liquid, as the familiar water, and
• gas, as water vapour.
• Difference in the 3 states of matter is due to difference in the spaces
in between the constituent particles.
• This interparticle space is inversely proportional to interparticle force
of attraction.
• Change in one of this can lead to change in states of matter.
• Two ways to achieve
By changing the temperature
By changing the pressure.

19. Effect of change of temperature
• 1 (a)Change of state from solid to liquid- Melting
(b)Change of state from liquid to solid- Freezing
• 2 (a)Change of state from liquid to gas- Boiling
(b)Change of state from gaseous to liquid- Condensation

20. Melting
Heating
Temperature
increase
Kinetic energy
increase
Particle start
vibrating with
speed
Decreasing the
force of
attraction
Particle leaves
their fixed
position
Strat flowing
Solid melts
Converted into
liquid

21. Definition of melting point
• The temperature at which a solid melts to become a liquid at atmospheric pressure is
called melting point.
• The process of melting i.e., change of solid states into liquid state is also called fusion.
Latent heat of fusion
The amount of heat energy
required to change 1 kg of a
solid into liquid at
atmospheric pressure at its
melting point is called latent
heat of fusion

22. Freezing
cooling
Temperature
decrease
Kinetic energy
decrease
Particle stop
vibrating with
speed
increasing the
force of
attraction
Particle start
moving slowly
If temperature
lowered
further,
Attractive force
pull the particle
close together
Substance
freeze

23. Definition of freezing point
• The temperature at which a liquid freezes to become a solid at atmospheric
pressure is called freezing point.
• The process of freezing i.e., change of liquid states into solid state is also called
solidification.
• Effect of addition of impurities on the freezing point.
impurities lowers the freezing point of liquids.
ex. 30% of CaCl2 in water freeze at 218 K (? oC) as compared to a solution of
sodium chloride in water freeze at 255 K (? oC) .

24. Questions????????
1. What is the effect of impurities on freezing point?
2. What is latent heat of fusion?
3. Why ice is more effective in cooling than water at same
temperature (00C)?

25. Boiling
heating
Temperature
increase
Kinetic energy
increase
Particle start
vibrating with
speed
decreasing the
force of
attraction
Particle start
moving fast
If temperature
increased
further,
the particle
leave their
place
Substance boils
(liquid to gas)

26. Definition of boiling point
• The temperature at which a liquid starts boiling at atmospheric
pressure is called its boiling point.
• Each pure liquid has a fixed boiling point, for example, pure water has
boiling point of 373 K (1000C).
• Higher the boiling point , stronger the force of attraction.
• Volatile liquids- low boiling point and weak force of attraction
ether -308 K, acetone – 329 K, alcohol -351 K etc…
• Non-volatile liquids- high boiling point and strong force of attraction
glycerol -470 K, glycerine – 488 K etc…

27. Latent heat of vaporization
• Temperature remain constant during boiling…where that heat will go…?
• The amount of heat energy that is required to change 1 Kg of liquid into vapors
at atmospheric pressure at its boiling point is called latent heat of vaporization.

28. Effect of impurities on boiling point of liquid.
• Boiling point of pure liquid is fixed
• But addition of salt or other impurities increase the boiling point of
liquid.
• For example, 60% solution of urea raises the boiling point of water by 0.52 K
Effect of pressure on boiling point of liquid.
• The boiling point of liquid depends on the pressure acting on it.
• It increase , if the pressure is increased, and it decreased if the
pressure is decreased.
• At sea level water boils at 373 K where pressure is 1 atm. But on mountain it
boils at lower temperature where pressure is less than 1 atm. And inside
pressure cooker it boils at higher temperature where pressure is more…..

29. Condensation
• Change of gas to liquid.
• When a gas or vapour cooled by
decreasing the temperature, the
kinetic energy of their constituent
particles decreased.
• Due to that particles start moving
slowly.
• As the temperature further lowered,
the attractive force pull particles close
together and the vapour condenses
i.e. gas or vapour converted to liquid.

30. Sublimation
• Direct conversion of solid into gas.
• Only those substance whose vapour
pressures become equal to atmospheric
pressure before their melting points are
capable of undergoing sublimation.
• Dry ice sublime at -780C (195 K).
• Examples:- ammonium chloride,
camphor, naphthalene, anthracene,
benzoic acid, iodine etc…

31. Experiment
• Take some camphor or ammonium
chloride. Crush it and put it in a china
dish.
• Put an inverted funnel over the china
dish.
• Put a cotton plug on the stem of the
funnel, as shown in Fig.
• Now, heat slowly and observe.
• What do you infer from the above
activity?

32. Application of sublimation
• Useful in purification of solids which
sublime on heating and contain non-
volatile impurities.
• In very cold place, snow doesn’t melt
but sublime directly to vapour
• In frost-free refrigerators, ice on the
walls of the freezer sublimes when
warm air is circulated through the
compartment during the defrost
cycle.

33. Effect of pressure
• To convert gas into liquid and liquid into sold, interparticle space
should be decreased and interparticle force of attraction should be
increased.
• Two ways to achieve,
a. by applying pressure
b. by increasing temperature.

34. By applying pressure
• Take a certain volume of gas in
cylinder provided with piston.
• Now compress the gas by pushing the
piston.
• Consequently, interparticle space
decreased, and the gas particles come
so close together that they start
attracting one another strongly to
form liquid.
• In other words, the gas liquefied by
application of pressure.
• Ex. LPG – Liquefied Petroleum Gas.

36. By lowering temperature
• If we cool the gas, the kinetic energy decreases and the particles slow
down.
• As a result, interparticle distance decrease and interparticle force of
attraction increase which pull the gas particles close to form a liquid.
• Gases like ammonia, Sulphur dioxide, carbon dioxide, etc. can be
liquefied easily either by applying pressure at room temperature or by
cooling at atmospheric pressure.
• If carbon dioxide is cooled under high pressure, it can be directly
converted into solid carbon dioxide called dry ice.
• If pressure is decreased to one atmosphere, it sublimes, i.e. it directly
converted to gas.
• Why it is called dry?

37. Critical temperature & pressure

38. Evaporation- a surface phenomenon
• “ The phenomenon of change of liquid into vapors at any temperature
below its boiling point is called evaporation.”
Particles of
liquid move
constantly
Leads to
collision
Due to that,
particles move
with different
speed
Thus they have
different kinetic
energy
At any given
temperature,
Kinetic energy
of some particle
on surface is so
high to break
force of
attraction
Due to that
liquid
particle leave
the liquid
And
converted
into vapor

39. Factors affecting evaporation
1. Surface area- greater the surface area, more the evaporation.
2. Temperature- more the temperature, more will be evaporation. So
in summer, evaporation is high than in winter
3. Humidity- water vapor present in air. More the humidity, lesser the
evaporation. That is why, clothes get dried easily in summer than in
winter.
4. Speed of wind- more the speed, more will be the evaporation. So in
windy day clothes get dried faster than in normal day.
5. Nature of liquid- lesser is the boiling point, more is the tendency of
the liquid to evaporate. Force attraction will be less in liquid with
low boiling point so that they easily get evaporate.

40. Evaporation cause cooling
• Liquid particle having high kinetic energy leave the surface and get
converted into vapor.
• As a result, the kinetic energy of the remaining particles of liquid
decreases and hence the temperature falls.
• Thus evaporation cause cooling.

41. Examples
1. Sprinkling of water on the roof or open ground in summer
2. Pouring of acetone on palm.
3. Why do we wear cotton clothes in summer?
4. Perspiration keeps our body cold.
5. Why is ice rubbed on a burnt part of the skin?
6. Why surgeons often spray some ether on skin before performing
minor surgery?

42. Difference between evaporation and boiling
BOILING EVAPORATION
It takes place at particular
temperature when liquid is
heated.
It occurs at any temperature.
Boiling is bulk phenomenon Evaporation is surface
phenomenon
No cooling caused during boiling Evaporation always causes cooling