Matter:
The whole universe is made up of materials such as plants, animals, air,
stone, cloud, etc. These materials are termed as matter. Matter always have
a particular mass and volume. Modern day science typically divided the
properties of matter in two types, physical properties and chemical
properties. Early Indians used to believe that matter is made up of five
basic elements "Panch Tatva" that means air, earth, fire, sky and water.
Physical Nature of matter:
Matter is made up of small particles like sand. All the small particles of
same kind get clustered to form matter. Particles of matter can only be
viewed under a microscope. Any matter like a block of wood seems to be like
a continuous. But we can conclude that matter is made up of particles
because we see particles of sugar mixed with the particles of water when we
make a sugar and water solution.
Characteristics of Particles of Matter:
Particles of matter have space in between that can be observed when we mix
salt in water. Once it gets mixed up the salt particles move in between the
water particles. Particles of matter continuously moves as we see when we
drop ink in still water it mixes with the water uniformly after some time.
Particles of matter also have a force of attraction which helps them stay
together. The strength of this force varies between different kind of
matter.
States of Matter:
Matter around us exist in three different state - solid, liquid and gas.
These states are formed due to variation of the particle characteristics.
As we move from solid state to gaseous state the force of attraction
between the particles gradually decreases.
The Solid state:
Solid have a fixed shape and it tries to retain its shape. It can be
deformed under force but once removed it we change the shape though too
much force can lead to breakage. the particles in solid are closely packed.
Solid also have a fixed volume and district boundaries and not at all
diffusible.
The Liquid state:
Liquid have no fixed shape but have fixed volume. it always takes up the
shape of the container customers in which it is kept. Liquid diffuse more
quickly than solid that is due to the particles move freely and has greater
space between each other. The amount of diffusion of liquid is more than
solid because liquid contains dissolved oxygen and other solid particles.
The Gaseous state:
Gases do not have any fixed shape or volume. it is Highly compressible as
the particles are very loosely packed. Due to the loose packing of the
particles they moves freely at high speed show the particles meet each
other also the walls of the container they are kept in.
Change of State.
Matter changes its state from solid to liquid to gas while heating and just
opposite happens while cooling. Can not only change its States heating or
cooling but also can change by varying the pressure.
Solid to liquid (Fusion)
On increasing the temperature kinetic energy of the particles in a solid
increase and it starts vibrating with greater speed. And when the energy
supplied by the heating overcomes the attraction between the particles they
start moving more freely this changes its state from solid to liquid at a
particular point of time that is called the melting point and the process
is called fusion.
Liquid to Gas (Vaporization)
It is the phenomenon when liquid state changes to gaseous state. When the
temperature is further increased then the particles in the liquids becomes
freer and changes into the gaseous state.
Gas to Liquid (Condensation)
It is the phenomenon when gaseous state changes to liquid state. When the
temperature is decreased then the particles in the gas gains back the force
of attraction and changes into the liquid state.
Liquid to Solid (Solidification)
It is the phenomenon when liquid state changes to solid state. When the
temperature is further decreased then the particles in the liquid gains
back the force of attraction to such an extent that they stop moving and
changes into the solid state with a fixed structure.
Solid to Gas (Sublimation)
The process of change of solid state directly to the gaseous state without
going through the liquid state is called sublimation. Example: Sodium,
naphthalene, etc.
Gas to Solid (Deposition)
Process of change of gaseous state directly to the solid state without
going through the liquid state is called deposition.
Factors affecting evaporation:
Evaporation depends upon the surface area exposed, the temperature, the
humidity and the wind speed.
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Evaporation is a surface phenomenon due to which whenever the surface
area is increased the rate of evaporation also increase.
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An increase in temperature increase the rate of evaporation as per
kinetic energy of the particles increases
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A Decrease in humidity increase the rate of evaporation as humidity
determines the amount of water vapour present in the air.
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An increase in the wind speed increases the rate of evaporation. Because
when wind speed increases more water vapour moves away with the wind.
Evaporation cause cooling
It is because the particle of liquid when evaporated losses energy so it
tries to regain the energy from the surrounding and hence cools down the
surrounding by absorbing the heat of the surrounding atmosphere.
Latent heat of vaporization
It is the heat energy required to change 1 kg of a liquid to gas at
atmospheric pressure at its boiling point.
Latent heat of fusion
It is the amount of heat energy required to change 1 kg of solid into
liquid at its melting point.