class 9 chapter 2.pptx

CHAPTER - 2
IS MATTER AROUND US PURE

i)On the basis of the physical state, matter is classified into three main types.
They are solids, liquids and gases.
ii)On the basis of chemical composition matter is classified into two main
types. They are pure substances and mixtures.
 Pure substances are of two types. The are elements and compounds.
 Mixtures are of two types. They are homogeneous mixtures and
heterogeneous mixtures.
1) Classification of matter :-

Matter
Pure substance
eg. O2,H2O
Elements
eg. O2, H2, Ca
Compounds
eg. H2O
Mixters
eg. Air
Homogeneous Hetrogeneous
1) Classification of matter :-

i)Pure substance :- is a substance which consists of a single type
of substance (element or compound).
Eg:- iron, copper, hydrogen, oxygen, water, sugar, common salt etc.
Mixture :- is a substance which consists of two or more pure
substances.
Eg:- sea water, minerals, soil, air, sand and salt, sugar in water,
salt in water etc.
2) Pure substances and mixtures :-

Differences between pure substances and mixtures :-
2) Pure substances and mixtures :-
Sl.No. Pure substance
1. Pure substance consists of a single
type of substance
2. Pure substance cannot be
separated into other substances by
physical method
3. Pure substance has its own
a
a
a
definite properties.
Mixture
Mixture consists of two or more
pure substances.
Mixture can be separated into its
components by physical methods.
Mixture shows the properties of
its components.

Mixtures are of two types. They are homogeneous mixture and
heterogeneous mixture.
i) Homogeneous mixture :- is a mixture which has a uniform
composition.
 The particles of the mixture are not visible by the naked eye.
 The particles cannot be separated by filtration.
 The mixture is stable (the particles do not settle down).
 The path of a beam of light is not visible in the mixture.
Eg :- mixture of sugar in water, mixture of salt in water, mixture of
copper sulphate in water etc.
3) Types of mixtures :-

.
ii) Heterogeneous mixture :- is a mixture which has a non -
uniform composition.
 The particles are visible by the naked eye.
 The particles can be separated by filtration.
 The mixture is unstable (the particles settle down).
 The path of a beam of light is visible in the mixture.
Eg :- mixture of salt and sand, mixture of sulphur and iron
filings, mixture of oil and water etc.
3) Types of mixtures :-

3) Mixtures :-
In a mixture, the colloidal solution is one of the significant parts of the mix
with the two adjacent combinations: true solutions and suspension
solutions. All three solutions have variable characteristics and properties
in different physical and chemical procedures, and their significant
difference lies in the particles’ size, appearance, and separation
procedure. The three solutions react differently with the various chemical
processes. The three mixtures attain their differences with the dissolving
properties of the mixtures according to the variable nature of the solute
and solvents involved.

4. Solution (True solutions)
A solution is defined as a homogenous mixture which mainly
comprises two components namely solute and solvent.
eg. Lemonade, soda water, etc., are all examples of solutions.
solution are three types
 Liquid solutions- liquid that contains either a solid, liquid or a
gas dissolved in it.
 Solid solutions (alloys)
 Gaseous solutions (air).
In asolution there is homogeneity at the particle level.
For example, lemonade tastes the same throughout.

A solution has a solvent and a solute as its components.
The component of the solution that dissolves the other component in
it (usually the component present in larger amount) is called the
solvent.
The component of the solution that is dissolved in the solvent
(usually present in lesser quantity) is called the solute.

4. Solution
Examples:
a) A solution of sugar in water is a solid in liquid solution. In this
solution, sugar is the solute and water is the solvent.
b) A solution of iodine in alcohol known as ‘tincture of iodine’, has
iodine (solid) as the solute and alcohol (liquid) as the solvent.
c) (Aerated drinks like soda water, etc., are gas in liquid solutions.
These contain carbon dioxide (gas) as solute and water (liquid) as
solvent.
d) Air is a mixture of gas in gas. Air is a homogeneous mixture of a
number of gases. Its two main constituents are: oxygen (21%) and
nitrogen (78%). The other gases are present in very small
quantities.

Properties of true solutions :-
i) True solution is a homogeneous mixtureProperties of a Solution
ii) The particles of a solution are smaller than 1 nm (10-9 metre) in diameter.
So, they cannot be seen by naked eyes.
iii) Because of very small particle size, they do not scatter a beam of light
passing through the solution. So, the path of light is not visible in a solution.
iv)The solute particles cannot be separated from the mixture by the process of
filtration.
v) The solute particles do not settle down when left undisturbed, that is, a
solution is stable..

 At any particular temperature, a solution that has dissolved as
much solute as it is capable of dissolving, is said to be a saturated
solution.
 In other words, when no more solute can be dissolved in a solution
at a given temperature, it is called a saturated solution.
 The amount of the solute present in the saturated solution at this
temperature is called its solubility.
 If the amount of solute contained in a solution is less than the
saturation level, it is called an unsaturated solution.
.Concentration of a solution :-

9)
The concentration of a solution is the amount of solute present in
a given amount of the solvent or solution.
Amount of solute
Concentration of a solution =
Amount ofsolvent
Amount of solute
Or =
Amount of solution

9)
The concentration of a solution can be expressed as mass by mass
percentage or as mass by volume percentage.
Mass of solute
Mass by mass percentage of a solution = X 100
Mass of solution
Mass by volume percentage of a solution = X 100
Volume of solution
Concentration of a solution :-
Mass of solute

5) Colloidal
solution :-
A colloidal solution is a heterogeneous mixture of two or
more substances.
Eg :- mixture of starch in water, mixture of egg albumin in
water, milk, air containing dust and smoke etc.
Properties of colloidal solution :-
i) Colloidal solution is a heterogeneous mixture.
ii) The particles cannot be seen by the naked eye.
iii) The solute particles cannot be separated by filtration.
iv) The solute particles do not settle down and the solution
is stable.
v) The particles scatter a beam of light passing through it
and the path of light is visible in the solution.

Suspension
:- A suspension is a heterogeneous mixture of two or
more substances.
Eg :- solution of sand in water, solution of chalk powder
in water etc.
Properties of suspension :-
i) Suspension is a heterogeneous mixture.
ii) The particles can be seen by the naked eye.
iii) The solute particles can be separated by filtration.
iv) The solute particles settle down and the solution is
unstable.
v) The particles scatter a beam of light passing through
it and the path of light is visible in the solution.

Solute particles can be
separated by filtration.
Solute particles settle down
and the solution is unstable.
SUSPENSIO
N
Solute particles scatter light
and the path of light is visible.

7) Tyndall
effect :-
When a beam of light is passed through a colloidal
solution, the colloid particles scatter the beam of light and
the path of light becomes visible in the solution. This effect
is called Tyndall effect.
Tyndall effect can be seen when light enters a room
through a small hole due to scattering of light by the dust
and smoke particles.
Tyndall effect can be seen in a dense forest due to
scattering of light by water droplets in the mist.

8) Saturated
solution :-
Saturated solution :- is a solution which cannot dissolve
any more of a solute at a given temperature.
Solubility :- of a substance is the amount of solute
present
in a saturated solution of the substance.
Unsaturated solution :- is a solution which can dissolve
some more of the solute at a given temperature.
Preparation of a saturated solution :-
Take 50ml of water in two beakers. Add salt in one beaker
with continuous stirring till no more salt dissolves in it.
Similarly add sugar in the other beaker with continuous
stirring till no more sugar dissolves in it. We get saturated
solutions of salt and sugar.
If the mixtures are heated it dissolves some more of the
solute.
The solubility of different substances are different.
The solubility of substances varies with temperature.

10) Separating the components of
a mixture :-
The components of a heterogeneous mixture can be
separated by simple methods like hand picking, sieving,
filtration etc.
Sometimes special techniques are used to separate the
components of mixtures like :-
i) Evaporation
ii) Centrifugation
iii) Decantation (Using separating funnel)
iv) Sublimation
v) Centrifugation
vi) Chromatography
vii) Distillation and fractional distillation

Evaporation
:-
This method is used for separating a volatile component
(solvent) from a non volatile component (solute) by heating
the mixture.
Eg :- Ink is a mixture of a dye and water. If some ink is
heated in a dish, the water evaporates and the dye is left in
the dish. Similarly we can separate a mixture of salt and
water or sugar and water by evaporation.
dish
wire gauze
Mixture of salt and water
stand
burner

Centrifugation
:-
The method of separating denser particles and lighter
particles from a mixture by using a centrifuging machine
is called centrifugation.
Eg :- If we take some milk in a centrifuging machine and
spin it rapidly, the cream separates from the milk because
cream is less dense than milk.

iii) Decantation using separating
funnel :-
This method is used for separating a mixture of
immiscible liquids. Liquids separate into different layers
depending on their densities.
Eg :- If we take a mixture of kerosene oil and water in a
separating funnel, it forms separate layers of oil and
water. The water can be separated by opening the stop
cock. After the water flows out the stop clock can be
closed.
kerosene
water
water

Sublimation
:-
This method is used to separate a mixture of a
sublimable component from a non sublimable component
by heating the mixture.
Eg :- If a mixture of ammonium chloride and common
salt is heated, the ammonium chloride sublimes and can
be cooled and solidified and collected and salt is left
behind.
Mixture of
Ammonium chloride
and salt
Ammonium chloride
vapours
Ammonium chloride
solidified
Inverted funnel
Cotton
China dish
Burner

Chromatography
:-
This method is used for separating coloured components
from a liquid by using a filter paper or blotting paper.
Eg :- Put a drop of ink near one end of a strip of filter
paper and dip the end of the paper in a test tube containing
water. Ink is a mixture of two or more coloured
components. The component which is more soluble in
water rises faster and get separated.

vi)
Distillation :-
This method is used for separating a mixture of miscible liquids by
boiling the mixture and cooling and condensing the vapours.
Simple distillation :- is used for separating a mixture of two
miscible liquids having sufficient difference in their boiling points.
Eg :- If a mixture of acetone and water is heated in a distillation
apparatus, the acetone which has a lower boiling point than water first
boils and cools and condenses and is separated from the water.
Mixture of acetone
and water
Acetone

Fractional distillation :- is used for separating a mixture of two or
more miscible liquids whose difference in boiling points is less than 25K.
The apparatus used for fractional distillation is similar to that used
for simple distillation except that a fractionating column is fitted
between the distillation flask and condenser. The fractionating column
has glass beads which increases the surface for the vapours to cool
and condense.
Fractional distillation is used for separating the components of
petroleum, separating the different gases from air etc.
Mixture

11) Separation of components of air :-
Air is a mixture of gases. The components of air can be separated by
fractional distillation.
Air is compressed by increasing the pressure and cooled by
decreasing the temperature to get liquid air. The liquid air is then
allowed to warm up slowly in a fractional distillation column. Then the
different components separate at different heights depending on their
different boiling points.
Compress and cool by increasing
pressure and decreasing temperature
Allow to warm up slowly
In fractional distillation column
Gases get separated at different heights
Boiling points (OC) Oxygen – 183, Argon – 186 , Nitrogen – 196
Air
Liquid air

12) Purification of solids by
crystallisation :-
Crystallisation is the process of obtaining a pure solid in
the form of crystals from its solution.
Eg :- By crystallisation we can obtain pure copper
sulphate from its solution.
Dissolve about 5g of copper sulphate in minimum
amount of water. Filter the solution to remove the
impurities. Evaporate the solution in a china dish to get a
saturated solution. Cover the solution with a filter paper and
alllow it to cool. Pure copper sulphate crystals are formed.
Impure copper sulphate Pure copper sulphate crystals

13) Types of pure
substances :-
Pure substances are of two types. They are elements and
compounds.
i) Element :- is a basic form of matter which cannot be broken down
into simpler substances by chemical reactions. Elements are of
three types. They are metals, non metals and metalloids.
Properties of metals :-
They have lustre. They are malleable and ductile. They are good
conductors of heat and electricity. They are sonorous.
Eg :- iron, aluminium, zinc, mercury, copper, silver, gold etc.
Properties of non metals :-
They do not have lustre. They are not malleable or ductile. They are
poor conductors of heat and electricity. They are not sonorus.
Eg :- hydrogen, oxygen, nitrogen, iodine, carbon, sulphur,
phosphorus etc.
Properties of metalloids :-
Metalloids are elements which show some properties of metals and
some properties of non metals.
Eg :- boron, silicon, germanium etc.

ii) Compound :-
A compound is a substance composed of two or more elements
chemically combined together in a fixed ratio.
Eg :- water, carbon dioxide, sugar, salt, iron sulphide etc.
Differences between mixtures and compounds :-
Sl.No. Mixture
1 It is composed of two or more
elements or compounds
mixed together.
2 The composition of the
components is in any ratio.
Compound
It is composed of two or more
elements chemically combined
together.
The composition of the
components is in a fixed ratio.
3 It shows the properties of the
components.
It shows different properties
than the components.
4 The components can be
separated by physical
methods.
The components can be
separated only by chemical
methods.

class 9 chapter 2.pptx

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