CLASS 9 IS MATTER AROUND US PURE PRESENTATION

1. IS MATTER AROUND US PURE

2. MATTER
Anything which has mass and occupies space is called matter.
TYPES OF MATTER
On the basis of physical state:
1. Solid
2. Liquid
3. Gas
On the basis of composition:
1. Pure substances
2. Mixtures

4. 1. PURE SUBSTANCE
It may be defined as a material which contains only one kind of atoms or molecules.
 Properties Of Pure Substances
1) Pure substances are mostly homogeneous in nature containing only one type of
atoms or molecules.
2) These substances mainly have a constant or uniform composition throughout.
3) The substances have fixed boiling and melting points.
4) A pure substance usually participates in a chemical reaction to form predictable
products.
 Pure substances are again of two types:
1) Elements
2) Compounds
1. .

5. 1. Elements:
• Pure substances which are made up of only one kind of atoms are known as
elements.
• They cannot be split up into two or more simpler substances by any of the usual
chemical methods.
• For example, Iron, gold, silver, carbon, oxygen, nitrogen and sodium etc.
Elements are further grouped into the following three categories
1. Metals, for example: Iron, copper, gold, sodium, silver, mercury, etc.
2. Non – metals, for example: Carbon, oxygen, sulphur, nitrogen, oxygen, hydrogen, etc.
3. Metalloids : Boron, silicon, germanium, etc.

6.  Properties of Metals
These are lustrous (shine).
They conduct heat and electricity.
All metals are malleable and ductile.
They are sonorous.
All metals are hard except sodium and potassium.
All metals are solids at room temperature except mercury which is a liquid.
 Properties of Non-metals
•These are dull in appearance.
•They are poor conductors of heat and electricity except diamond which is a good
conductor of heat and graphite which is a good conductor of electricity.
•They are neither malleable nor ductile.
•They are generally soft except diamond which is the hardest natural substance known.
•They may be solids, liquids or gases at room temperature.
 Metalloids
The elements that have properties intermediate between those of metals and non-metals, are
called metalloids.

7. 2. Compounds
Compound is a pure substance made up of two or more elements combined
chemically in a definite ratio.
 Types of Compounds
1. Organic compounds(e.g. Carbon compounds like methane etc.)
2. Inorganic compounds(e.g. NaCl, marble etc.)
 Properties of compounds
1. The properties of compound differ from those of its constituents.
2. Compound has fixed melting point and boiling point.
3. Compound is a homogeneous substance.
4. Constituent elements can be separated by chemical process.

8. Impure Substance
It may be defined as a material which contains only one kind of atoms or molecules.
It is also named as mixture.
Mixtures
A mixture is a material which contains two or more different kinds of particles (atoms or
molecules) which do not react chemically but are physically mixed together in any proportion.
Types of mixture
It is of two types:
(a) Homogeneous mixture
(b) Heterogeneous mixture

9. S. No. Homogeneous mixture Heterogeneous mixture
1. All the components of the mixture are uniformly
mixed.
All the components of the mixture are not thoroughly
mixed.
2. No separation boundaries are visible. Separation boundaries are visible.
3. It consists of a single phase. It consists of two or more phases.
4. Example: Sugar dissolved in water Example: Air, sand and common salt.

11. Solution
A solution is a homogeneous mixture of two or more substances. For example: Lemon
water, sugar solution, soda water, etc.
Components of Solution
(1)Solvent
The component of the solution that dissolves the other component in it and is usually
present in larger amount, such component of solution is called the solvent.
For example: Water, alcohol etc.
(2) Solute
The component of the solution that is dissolved in the solvent and is usually present in
lesser quantity, such component is called the solute. For example: Salt, sugar, iodine etc.

12. Properties of solutions
(i) It is a homogeneous mixture.
(ii) Particle size in a solution is less than 1 nm in diameter.
(iii) Particles of a solution cannot be seen even with a microscope.
(iv) A true solution does not scatter the light.
(v) Solution is stable.
(vi) The solute particles cannot be separated from the mixture by the process of
filtration.

13. TYPES OF SOLUTIONS

14. Solubility
The maximum amount of the solute which can be dissolved in 100 grams of a solvent
at a particular temperature is known as its solubility in that particular solvent.
Conditions Affecting Solubility
(i) Temperature:
Solubility of solids in liquids increases with the increase in temperature, whereas
solubility of gases in liquids decreases on increasing the temperature.
(ii) Pressure:
Solubility of gases in liquids increases on increasing the pressure, whereas the
solubility of solids in liquids remains unaffected by the change in pressure.

15. Concentration of a Solution
It is defined as the mass of the solute in grams present in 100 grams of the solution.
Mathematical Expression For Concentration Of Solution:
In case of liquid solute in liquid solvent concentration can be expressed as:

16. Saturated Solution
A solution in which no more quantity of solute can be dissolved at a particular temperature,
is called saturated solution.
Unsaturated Solution
A solution in which more quantity of solute can be dissolved without raising its temperature,
is called unsaturated solution.
Suspension
• The heterogeneous mixture in which solids are dispersed in a liquid are called
suspensions.
• For example, chalk-water mixture, muddy water, flour in water, etc.
• A suspension is a heterogeneous mixture in which the solute particles do not dissolve but
remain suspended throughout the bulk of the medium.

17. Properties of a Suspension
1. It is a heterogeneous mixture.
2. The particles of a suspension can be seen by
naked eyes.
3. The particles of a suspension scatter a beam
of light passing through it and make its path
visible.
4. A suspension is unstable.
5. Constituents of a suspension can be
separated by the process of filtration.

18. COLLOID OR COLLOIDAL SOLUTION
Solutions in which the size of particles lies in between
those of true solutions and suspensions are called colloidal
solutions or simply colloids. For example, Milk, smoke and
starch solution, etc.
Properties of Colloids
1. A colloid is a heterogeneous mixture.
2. The size of particles of a colloid is too
small to be individually seen by naked
eyes.
3. The particles of a colloidal solution are big
enough to scatter a beam of light
passing through it.
4. A colloid is quite stable.
5. Colloidal particles cannot be separated by
the process of filtration.

19. Tyndall Effect
The scattering of light by the colloidal particles is known
as Tyndall effect.
It can be observed when:
•A fine beam of light enters a room through a small hole.
•Sunlight passes through the canopy of a dense forest.
NOTE
The colloidal particles are not the true solutions as their
particles are big enough to show the Tyndall effect, whereas the
particles of a true solution do no show Tyndall effect.

20. The Components Of A Colloidal Solution
1. Dispersed Phase:
The solute-like component or the dispersed particles in a colloid
form the dispersed phase.
2. Dispersion Medium:
The component in which the dispersed phase is suspended is known as the
dispersing medium.
Types of Colloids
Different types of colloids are discussed in the table given below:

21. Physical Change
Those changes in which only physical properties of the substances change but no new
substances are formed are called physical changes.
For example - Melting of ice to form water, breaking of glass, preparing a solution etc.
Chemical change
Those changes in which new substances are formed are called chemical changes and chemical
properties of a substance gets changed in a chemical change.
For example - Rusting of iron, burning a piece of paper etc.

22. Sl. No. Physical Change Chemical Clhange
1. Here only the physical properties like state,
shape or size of a substance change.
It brings about a change in the chemical
properties of a substance.
2. There is no change in chemical
composition of a substance.
There is always a change in chemical
composition of a substance.
3. No new substance is formed. A new substance is always formed.
4. It is temporary and hence reversible. It is permanent and hence irreversible.
Difference between Physical and Chemical changes:

23. The Separation Of Components Of A Mixture
Some of the important methods used to separate different mixtures are explained below
1.Evaporation
Evaporation is a process which is used to separate a solid substance dissolved in liquid.
It is based on the fact that liquids vaporize easily whereas solids do not.
Applications of Evaporation
•Obtaining salt from see water.

24. 2.Centrifugation
It is a method of separating the suspended particles of a substance from a liquid in which the
mixture is rotated at high speed in a centrifuge.
This method is useful in case the suspended particles in a liquid are too small too be retained by
filter paper.
 Principle of Centrifugation:
When a mixture is rotated very fast, the denser particles are forced to go to the bottom of
the centrifuge and the lighter particles stay at the top.
 Applications of Centrifugation
•Used in dairies to separate cream from milk.
•Used in washing machines to squeeze out water from wet clothes.

25. 3. Separating funnel
It is used to separate a mixture of two immiscible liquids, like
oil and water.
 Principle of Separating funnel
When a mixture of two immiscible liquids is kept in a
separating funnel, the liquids separate out in layers depending on their
densities with the heavier forming the top layer.
 Applications of Separating funnel
•To separate mixture of oil and water.
•In the extraction of iron from its ore where the lighter slag
(molten waste material) is removed from the top by to leave the
molten iron at the bottom of the blast furnace.

26. 4.Sublimation:
This method is used to separate those components from a
mixture which can sublime on heating.
For example: Ammonium chloride, camphor, naphthalene etc. can
be separated from their mixture by sublimation.
 Applications of Sublimation:
•Iron can be separated from a mixture of iron fillings and
camphor (volatile).
•Common salt can be separated from a mixture of salt and
ammonium chloride (volatile).

27. 5.Chromatography
This method is used to separate two or more dissolved solids
which are present in a solution in very small quantities.
 Principle of Chromatography:
This method of separation is based on the fact that though
two substances are dissolved in the same solvent but their
solubilities can be different. The component which is more
soluble in, rises faster and gets separated from the mixture.
 Applications of Chromatography:
•To separate colors in a dye by paper chromatography.
•To separate drugs from blood.

28. 6. Distillation
This method is used to separate a mixture solid in a
liquid. It is the process of heating the liquid to form vapour,
and then cooling the vapour to get back liquid.
It is used for the separation of components of a mixture
containing two miscible liquids that have sufficient difference
in their boiling points.
 Principle of Distillation
The volatile liquid evaporates on heating which can be
recovered by cooling its vapours by the process of
condensation.
 Applications of Distillation
•It is used to remove salt from sea water to obtain
drinking water.

29. 7.Fractional distillation
It is the process of separating two or more miscible liquids by distillation, the distillate being
collected in fractions due to boiling at different temperatures.
 Fractionating Column
The apparatus used in this process is similar to that for simple distillation except a fractionating
column which is fitted in between the distillation flask and the condenser. A simple fractionating
column is a tube packed with glass beads. The beads provide surface for the vapours to cool and
condense repeatedly.
 Principle of Fractional Distillation:
In a mixture of two or more miscible liquids, the separation of various liquids depends on their
boiling points. The liquid having lower boiling point boils first and can be obtained first from the
fractionating column than the liquid having higher boiling point.
 Applications of Fractional Distillation:
•It is used to separate a mixture of miscible liquids like alcohol-water mixture.
•It is used to separate crude oil ‘petroleum’ into useful fractions like kerosene, petrol, diesel, etc.
•It is used to separate different gases of the air by taking the liquid air.

31. 8.Crystallisation
Crystallization is a process used to separates a pure solid in the form of its crystals from a
solution. The process involves cooling a hot, concentrated solution of a substance to obtain
crystals.
 Applications of Crystallization
•Purification of common salt obtained from sea water.
•To obtain crystals of alum from impure samples.
•To obtain pure copper sulphate from an impure sample.