1 | Page RAJIV SHARMA CLASSES 9312437824 BY VIVEK MISHRA MATTER IN OUR SURROUNDINGSMATTER:-anything which occupies space and has mass is called Matter. Air and Water; hydrogen and oxygen; classifi ed in many ways. Modern day scientists have classifie d matter in two ways : 1.On the basis of its physical its physicalproperties matter can be classified in to t hree ways: i.Solidsii.Liquidsiii.Gas2.On the basis ofchemicalpropertiesmattercan be classified into three parts:i.Elementii.Compoundiii.MixtureMATTER IS MADE OF PARTICLESEvery matter around us is made of tiny particles. T he number of particle in a matter is very larg e. The particles of matter are very large even we cannot s ee them with high power microscope. The particles which make up matter are constantly moving. Theparticles whichmakeupmatterare AtomsorMolecule . Characteristicsofparticlesofmatteri.The particles of matter are very s mall. ii.The particles of matter hav e spaces between them. iii.The particles of matter are constantly mo ving. iv. The particles of matter attract each other. CL ASSIFICATION OF MATTER AS SOLIDS, LIQUIDS AND GASESMatter exists in three physical st ates : SOLIDS, LIQUIDS AND GASES. 1.PROPERTISE OF SOLIDSi.Solds have fixed shape and volume ii. Solids cannot be compressed. iii.Solids have high densities. iv.Solids dont fill their container completely. v. Solids dont flow. vi.Solids are rigid.2.PROPERTIS OFLIQUIDSMATTER SOLIDS LIQUIDS GASES
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iv . Liqui s cannot f ill their cont ainer complet ely.
v . Liqui s flow easily. Therefore they are called Fluids
3. PR
OPERTISE
OF G A SES
i . Gases neither have f ixed volume nor have f ixed mass.
ii . Gases can be compressed complet ely and easily.
iii . Gases have very low densities.
iv . Gases f ill their cont ainer complet ely.
v . Gases flow easily, Therefore they are called fluids.
SOLIDS
In solids particles are closely packed. A solid has fixed shape because the particles of thesolid are closely packed and their positions are fixed due to the strong force of attraction
between them. A solid has fixed volume and can not be compressed because the spaces
between its particles is fixed. A solid can not fill the container completely and cannot flow
because its particles are closely packed.
A rubber band changes its shape but we still call it a solid because it changes its shape
by the action of force and when the force is removed the rubber band rega ins its
shape.
I f salt and sugar not appear to have fixed shape but we still count them in solids
because the shape of the individual crystals is considered to be solid because the shape
of individual crystals is fixed. A sponge can be compressed easily but still we count them in solids because they have
minute pores in it which are filled with air. When we press the sponge air is expelled
from its holes making it highly compressible.
A solid cannot be compressed by either applying the pressure or by changing the
temperature.
LIQUIDS
In the liquids the particles are close together but they are not as close as solids. Spaces
between particles in liquids are slightly more than in solids. There is weaker force of attraction between the particles of liquids than in solids. They don¶t have fixed shape because
the positions of its particles are not fixed due to comparatively less strong force of attraction
between them. a liquid has fixed volume because at the given temperature, the spaces
between its particles are fixed. a liquid can not be compressed much because they have less
space between the particles of them. A liquid generally flows easily because its particles are
able to slide over another due to slightly weaker interparticle forces of attraction.
5 | P a g e R A J I V S H A R M A C L A S S E S 9 3 1 2 4 3 7 8 2 4
BY VIVEK MISHRA
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The changing up of sollid into vapours on heating and of vapour s into solid on
cooling is known as Sublimation. The cooman substances which h undergo
sublimation are ammonium chloride, iodine, camphor, naphthalene, and
anthracene.
LAT E T H EAT
The heat energy which has to be supplied to change the state of a substance. Latent hest
does not change the temperature of a substance. It only changes the state of a substance. It
is called latent heat because it becomes hidden in the substance undergoing the change of
state, and does not show its presence by raising temperature. So latent heat cannot be
detected by thermometer.
Why latent heat does not cause a rise in temperature of a substance?
The latent heat which we supply is used up in overcoming the force of attraction
between the particles of a substance during the change of state. Latent heat does notincrease the kinetic energy of the particles of the substance. And since there is no
change in kinetic energy of the particles the temperature of a substance does not rise
during the change in state.
LATENT HEAT IS OF TWO TYPES;
1. Latent heat of fusion
2. Latent heat of vaporization.
LAT E p
T H EAT Oq
F U S I Op
(S OL ID T O L I QU ID CH Ap
GE)
The latent heat of fusion(melting) in of a solid is the quantity of heat in joules required to
convert 1 kilogram of the solid to liquid without any change in temperature. The latent heatof fusion of ice is 3.34×105 joules per kilogram.
Why t he temperature of melting ice does not rise even t hough heat is being
supplied continuousl y ?
In this process heat energy is used up in changing the state of solid substance by
overcoming the force of attraction between its particles. So amount of particles in
water at 00 C have more energy as compared to particles in ice at the same
Some particles in liquid always have more kinetic energy than others. So even when a liquidis below its boiling point, some of its particles have enough energy to break the force of
attraction between the particles and escape from the surface of the liquid in the form of vapor.
F ACT ORS AFFE CT IN G EV APOR AT ION 1. T
EMPER AT
URE The rate of evaporation increases on increasing the temperature of the liquid. an
increase of temperature: With the increase of temperature, more number of particlesget enough kinetic energy to go into the vapor state.
2. SURF AC E ARE A OF LIQUID
an increase of surface area: We know that evaporation is a surface phenomenon. If thesurface area is increased, the rate of evaporation increases. For example, while putting
clothes for drying up we spread them out.
3. � H UMIDI TY OF A IR
Humidity is the amount of water vapour present i n air. The air around us cannothold more than a definite amount of water vapour at a given temperature. If theamount of water in air is already high, the rate of evaporation decreases.
4. W IND SPEED
� an increase in wind speed: It is a common observation that clothes dry faster on awindy day. With the increase in wind speed, the particles of water vapour move away
with the wind, decreasing the amount of water vapour in the surrounding.
W hat i s t he c au se of cooli n g c au sed by evaporation?
When a liquid evaporates it draws the latent heat of vaporization from anything whichit touches. By losing heat the substance gets cooled.
1. If we put A little of spirit or patrol at the back of our hand and wave it around the
spirit evaporates rapidly and our hands feels very cold. This is due to the fact thatto \change from liquid to gas state spirit requires latent heat of vaporization whichspirit takes by our hand. Our hand looses heat and gets cooled.
2. During hot summer days water is usually kept in earthen pots to keep it cool. The
earthen pot has a large number of pores in its walls. Some of water continuouslyseeps out through these pores. This water evaporate and continuously and takes
the latent heat of vaporization from the surface of the pot and remaining water. In
this way remaining water looses heat and becomes cool.3. Respiration or sweating is our body¶s method of maintain constant temperature. On
a hot day or after doing some physical exercise. When our body temperature tends
to rise too much our sweat glands give out moisture on our skin. When the sweatevaporates it takes the latent heat of vaporization from our body. This keeps ourbody cool.