MATTER

Matter is anything that occupies space and has mass.

Matter is made up of tiny and discrete particles.

These particles are: Atom. Molecule. Ion.

Matter exist in 3 states :-

Solid

Liquid

Gas

Solid .

A solid has afixed volumeand shape.

A solid cannot be compressed

The particles are packed closely together in an orderly manner.

There are strong forces between the particles.

The particles can only vibrate and rotate about their fixed positions.

Liquid

A liquid cannot be compresseasily.

A liquid has a fixed volume. It does not have a fixed shape but takes the shape of the container.

The particles are held together by strong forces butweaker than theforces in a solid.

The particles can vibrate,rotate and move throughout the liquid. They collide against each other

The particles areclosely togetherbut not in orderly arrangement

Gas

A gas does not have a fixed shape or volume.

A gas canbe compressed

easily.

The particles are veryfar apart from each other and in a randommotion.

There are weak forces between the particles.

The particles can vibrate, rotate and move freely. The rate of collision is greater than the rate of collision in a liquid.

Inter-conversion of the state of matter

GAS

SOLID LIQUIDKey : :heating

:cooling

Subl

imat

ion evaporation

condensation

freezing

melting

Subli

mat

ion

decreasing heat

increasing heat

solid liquid

The change in heat affects the kinetic energy of particles

gas

Melting pointWhen solid is heated , the particles in thesolid gain kinetic energy and vibrate morevigorously.

The particles vibrate faster as thetemperature increases until the energy theygained is able to overcome the forces thathold them at their fixed position.

At this point, the solid become liquid

This process called melting

The temperature at which this happen iscalled the melting point.

Freezing Point When a liquid is cooled, the particles in the

liquid lose energy and move slower.

As the temperature continues to drop, the particles continue to lose more energy until they do not have enough energy to move freely.

At this point, the liquid changes into the solid

This process is called freezing

The temperature at which this happen is called freezing point

Meltingpoint

Temperature (°c)

Time (min)

The heating curve

A

B C

D

At point A :-The matter exists as solid. When the solid

is heated, heat energy is absorbed.This cause the particles to gain kinetic

energy and vibrate faster.This is why the temperature increases.

At point B to C :-The solid begin to meltBoth liquid and solid are presentDuring the melting process , the

temperature of the matter does not rise, even though heating continues.

The temperature remain constant because the heat energy absorb by the particles is used to overcome the forces between particles so that the solid can turn into liquid.

This constant temperature is the melting point of the matter.

At point C and D :-

All the solid has melted and change to the liquid

From point C to Point D, the particles in liquid matter absorb heat energy and move faster.

The temperature increases from point C to D.

The cooling curveTemperature

(°c)

F G

H

E

Time (min)

Freezing point

At point E to F :

The particles in the liquid lose their kinetic energy

They move slower as the temperature decrease

At point F :-

The liquid matter begins to freeze.

Its temperature remains constant because the heat loss to the surroundings is exactly balanced by the heat energy liberated as the particles attract one another to form solid

At point G to H:-

The solid is cooled

The particles in the solid vibrate slower as the temperature decreases