PPT FOR CBSE, ICSE BOARD,
CHAPTER 1: MATTER IN OUR SURROUNDING
MATTER, PROPERTIES OF MATTER, CHARACTERISTICS OF MATTER, DIFFUSION, EVAPORATION, SUBLIMATION, KEY OINTS, NOTES.
EXPERIMENTS: PARTICLES OF MATTER ARE VERY SMALL
PARTICLES OF MATTER ARE ALWAYS MOVING
PARTICLES OF MATTER HAVE SPACE BETWEEN THEM.
POTASSIUM PERMANGANATE EXPERIMENT
3. CHARECTERISTICS OF MATTER
The particle of matter are very very small.
The particles of matter have space between them.
The particles of matter are continuously moving.
The particles of matter attract each other.
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4. The particle of matter are very very
small.
TO SHOW THAT PARTICLES OF MATTER ARE SMALL
Take 2-3 crystals of potassium permanganate and dissolve them in 100mL of water.
Take out approximately 10mL of this solution and put it into 90mL of clear water.
Take out 10mL of this solution and put it into another 90mL of water.
Keep diluting the solution 5-8 times.
Observance : this experiment shows that just a few crystals of permanganate can colour a large amount of
water(say 1000mL).
Conclusion :
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6. The particles of matter have space
between them.
TO SHOW THAT PARTICLES OF MATTER HAVE SPACE BETWEENTHEM
We take about 100 mL of water in a beaker. And mark the level of water in the beaker with a marking pen.
Now add 50gm of sugar to the beaker and dissolve it by stirring it with a glass rod. When all the sugar has dissolved, we get
a sugar solution.
Now look at the level, is it at the same level or it is displaced?
OBSERVANCE : WE WILL FIND THAT EVEN AFTER DISSOLVING 50gm OF SUGAR, THE VOLUME HAS NOT INCREASED.
CONCLUSION : THE PARTICLES OF MATTER HAVE SPACE BETWEEN THEM.
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8. The particles of matter are
continuously moving.
THE BEST EVIDENCE THAT PARTICLES OF MATTER ARE CONSTANTLY
MOVING COMES FROM THE STUDIES OF DIFFUSION AND BROWNIAN
MOTION. EXAMPLES:-
a) when we light an incense stick (agarbatti) in one corner of a room, its fragrance spreads in
the whole room quickly
b) When a few crystals of copper sulphate are placed at the bottom of a beaker containg water,
then water in the whole beaker turns blue slowly.
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9. The particles of matter attract each
other.
There are some forces of attraction between the particles of
matter which bind them together.
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10. CLASSIFICATION OF MATTER
Early Indian philosophers classified matter in the form of five basic
elements- the ‘panch tatva’ – air, water, earth, fire and sky.
Modern scientists have evolved two types of classification of matter based
on its physical properties and chemical aspects.
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12. SOLID
In solids, the particles are closely packed.
Solids have a fixed shape and a fixed volume.
Solids cannot be compressed much.
Solids have high densities. They are heavy.
Solids do not flow.
Solids have great force of attraction.
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13. LIQUID
In liquids, the particles are close together, but they are not as close as in
solids.
Liquids have a fixed volume but they have no definite shape. Liquids take
the shape of vessel in which they are placed.
Liquids cannot be compressed much.
Liquids have moderate and high densities. They are usually less dense than
solids.
Liquids generally flow easily.
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14. GAS
Gases have neither a fixed shape nor a fixed volume.
Gases can be compressed easily.
Gases have very low densities. They are very, very light. A gas is much
lighter than the same volume of solid or gas.
Gases flow easily.
In solids, the particles are much farther apart from one another as
compared to solids and liquids.
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15. BOSE-EINSTEIN CONDENSATE
The BEC happens at super low temperatures. We have talked about
temperature scales and Kelvin. At zero Kelvin (absolute zero) all
molecular motion stops. Scientists have figured out a way to get a
temperature only a few billionths of a degree above absolute zero. When
temperatures get that low, you can create a BEC with a few special
elements. Cornell and Weiman did it with rubidium (Rb).
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16. PLASMA
A plasma is a gas that has been energized to the point that some of the
electrons break free from, but travel with, their nucleus. Gases can become
plasmas in several ways, but all include pumping the gas with energy. A
spark in a gas will create a plasma.
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17. DIFFUSION
The spreading out and mixing of a substance with another substance due
to the motion of its particles is called diffusion.
Diffusion is a property of matter which is based on the motion of its
particles. Diffusion is fastest in gases and slowest in solids.
The rate of diffusion increases on increasing the temperature of the
diffusing substance.
Diffusion is fastest in gases and slowest in liquid.
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18. SI UNIT OF TEMPREATURE
The common unit of measuring
temperature (like melting points, boiling
points, etc.).
There is another scale of temperature called
kelvin scale of temperature which is used by
the scientist mainly for research work. The SI
unit of measuring temperature is kelvin (K).
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20. EFFECT OF CHANGE OF TEMPERATURE
By increasing the temperature, a solid can be converted into liquid
state; and the liquid can be converted into gaseous state.
By decreasing the temperature, a gas can be converted into liquid
state; and a liquid can be converted into solid state.
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21. SOLID TO LIQUID: MELTING
The process in which a solid substance changes into a liquid on heating, is
called melting (or fusion).
The temperature at which a solid substance melts and changes into a
liquid at atmospheric pressure is called melting point.
The melting point of a solid is a measure of the force of attraction between
its particles (atoms or molecules).
When a solid is heated sufficiently, it changes its physical state and
becomes a liquid.
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22. LIQUID TO GAS: VAPORISATION
The process in which a liquid substance changes into a gas rapidly on
heating is called boiling.
The temperature at which a liquid boils and changes rapidly into a gas at
atmospheric pressure, is called boiling point of the liquid.
The boiling point of liquid is a measure of the force of attraction between
it’s particles.
When a liquid is heated, it changes its physical state and becomes a gas.
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23. GAS TO LIQUID: CONDENSATION
The process of changing a gas( or vapor) to a liquid by cooling, is called
condensation.
Please note that condensation is reverse of boiling.
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24. LIQUID TO SOLID: FREEZING
The process of changing a liquid into a solid by cooling, is called freezing.
Freezing means solidification.
Please note that solidification is reverse of melting.
The state of matter can be changed by changing the temperature (by
heating or cooling).
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25. LATENT HEAT
The heat energy which has to be supplied to change the state of a
substance is called its latent heat. Latent heat does not raise the
temperature. But latent heat has always to be supplied to change the
state of a substance.
Why temperature does not rise? The latent heat which we supply is
used up in overcoming the forces of attraction between the particles of
a substance during the change of state.
Latent heat is of two types-
i) Latent heat of fusion.
ii) Latent heat of vaporization.
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26. LATENT HEAT OF FUSION
The heat energy which is required to change the state of matter from solid
to liquid is called latent heat of fusion.
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27. LATENT HEAT OF VAPORISATION
The heat energy required to change the state of matter from liquid to
gas is known as latent heat of vaporization
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28. SUBLIMATION
The changing of a solid directly into gas on heating, and of
vapors into solid on cooling, is known as sublimation
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29. EFFECT OF CHANGE OF PRESSURE
The physical state of matter can also be changed by changing the
pressure.
Gases can be liquefied by applying pressure and lowering temperature.
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30. EVAPORATION
The process of a liquid changing into vapor( or gas) is called evaporation.
FACTORS AFFECTING EVAPORATION
Temperature: the rate of evaporation increases on the increasing of
temperature.
Surface area: the rate of evaporation increases on the increasing of surface
area.
Humidity: when the humidity of air is low, then the rate of evaporation is
high.
Wind speed: the rate of evaporation increases on the increasing of wind
speed.
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31. COOLING CAUSED BY EVAPORATION
The cooling caused by evaporation is based on the fact that when
a liquid evaporates, it draws (or takes) the latent heat of
vaporization from ‘anything’ which it touches. By losing heat,
anything gets cooled.
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32. PRESENCE OF WATER VAPOUR IN AIR
Presence of water vapour can be shown by following:
We take a steel tumbler and put some well crushed ice into it. Wipe
the tumbler with a cotton cloth to make the surface clear and dry.
Allow the ice tumbler undisturbed for 5 minutes.
Observance: a large number of tiny droplets of water appear on the
outer surface of the tumbler.
Reason : the air around the steel tumbler contains water vapour in
it. When these water vapor come in contact with cold, outside
surface of tumbler, they condense to form tiny drops of liquid
water.
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33. KEY POINTS
1. Matter- Matter is anything which occupies space and has mass is called matter. Air and
water, sugar and sand, hydrogen and oxygen etc. Matter is made up of very small tiny particles.
Particles of matter have space between them they attract each other.
2. Classification- On the basis of physical properties, matter is classified as solids, liquids and
gases. On the basis of chemical properties, matter is classified as elements, compounds and
mixtures.
• Solids- Solids have strong molecular force and a definite shape and size solids can neither
flow nor be compressed.
• Liquids- Liquids have weak intermolecular flow and large intermolecular spaces. Liquids
do not have a definite shape but can flow.
• Gases- Gases have weak intermolecular flow, high compressibility, and no definite shape
and volume.
3. Physical properties of matter- Matter is made up of particles which are very small in size.
Everything around us is made up of tiny pieces or particles. The particles of matter are
constantly moving (they are in motion).The particles which make up matter are atoms and
molecules.
4. Interchange in states of matter- Matter can change its state in solid, liquid or gas depending
upon the type of matter.
5. Diffusion- The mixing of a substance with another substance due to the motion or
movement of its particles is called diffusion. It is one of the properties of materials. The
diffusion of one substance into another substance goes on until a uniform mixture is formed.
Diffusion takes place in gases, liquids and solids.
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34. 6. Latent heat- Latent heat is the heat energy which has to be supplied to change the state of
a substance. Latent heat does not increase the temperature of a substance. But latent heat has
to be supplied in order to change the state of a substance. Latent heat can be of fusion or of
vaporization.
7. Sublimation- The changing of a solid directly into vapours on heating and of vapours into
solid on cooling, is known as sublimation. When these solid substances are heated, their
particles move quickly and they separate completely to form vapor (or gas). Similarly when
these vapor (or gas) is cooled, these particles slow down so quickly that they become fixed
and form a solid.
8. Evaporation- The process of conversion of a liquid into vapour (or gas) at its boiling point
is called evaporation. Some particles in liquid always have more kinetic energy than the
others. So, even when a liquid is well below its boiling point, some of its particles have
enough energy to break the forces of attraction between the particles and escape from the
surface of the liquid in the form of vapour. Thus the fast moving particles of a liquid are
constantly escaping from the liquid to form vapor or gas. Temperature, surface area of liquid,
humidity, and wind speed are fators that affect evaporation. Evaporation causes cooling
effect.
9. Effect of Change of Pressure: The physical state of matter can also be changed by
increasing or decreasing the pressure to it. Gases can be liquefied by applying pressure and
lowering temperature. When high pressure is applied to a gas, it gets compressed, and when
in addition to it we lower its temperature, it gets converted into liquid. So, we can also say
that gases can be turned into liquids by compression and cooling.
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36. WHAT ARE CHARECTERISTICS OF MATTER?
Below are the characteristics of matter
The particle of matter are very small.
The particles of matter have space between them.
The particles of matter are continuously moving.
The particles of matter attract each other.
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37. What do you mean by following terms-
(a) evaporation
(b) sublimation
(c) condensation
Answer:
a) The process in which a liquid substance changes into a gas rapidly on
heating is called evaporation.
b) The changing of a solid directly into gas on heating, and of vapors into
solid on cooling, is known as sublimation.
c) The process of a liquid changing into vapor( or gas) is called evaporation.
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38. Define latent heat of fusion and latent of vaporization.
The heat energy which is required to change the state of matter from solid
to liquid is called latent heat of fusion.
The heat energy required to change the state of matter from liquid to gas
is known as latent heat of vaporization
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