This PowerPoint Presentation will help the students of Class 9 to rejuvenate and to revise what they have learnt so far and to clear their doubts regarding any topic in this Chapter.

1. IS MATTER AROUND US PURE ?

2. MATTER
Pure Substances Mixtures
Elements Compounds Homogeneous
Mixture
Heterogeneous
Mixture

3. PURE SUBSTANCES
Pure Substances are substances that are made up of only one kind of particles and has
a fixed composition. For e.g., gold, water, bromine, salt, chlorine, etc.
• Pure substances are further classified as Elements and Compounds.
 Elements – An Element is a substance that consists of only one type or kind of atom.
It is a pure substance as it cannot be broken down or transformed into a new
substance by using physical or chemical means. They can be classified as Metals,
Non-Metals and Metalloids.
 Compounds – A Compound is also pure substance, when two or more elements are
combined chemically in a fixed ratio. These substances can be broken down into
separate elements by chemical methods.

4. METALS
The properties of Metals are:-
 They have a Luster (shine).
 They have a silvery – grey or a golden – yellow color.
 They are Good Conductors of heat and electricity.
 They are Ductile (can be beaten up into wires).
 They are Malleable (can be beaten up into sheets).
 They are Sonorous (produce ringing sounds when hit).
 They are Hard.
• For Examples – Gold, Silver, Iron, Copper, Aluminum, Potassium, etc.

5. NON – METALS
The properties of Non – Metals are:-
 They do not have a Luster (shine).
 They display a variety of colors.
 They are Poor Conductors of heat and electricity.
 They are Non - Ductile (can’t be beaten up into wires).
 They are Non – Malleable (can’t beaten up into sheets).
 They are Non – Sonorous (do not produce ringing sounds when
hit).
 They are not Hard.
• For Examples – Diamond, Coal, Oxygen, Chlorine, Sulphur, etc.

6. METALLOIDS
Elements that have intermediate properties of both metals
and non-metals, they are called Metalloids. Examples are
boron, silicon, germanium etc.
The properties of Metalloids are:-
Metalloids look like Metals, but behave like Non-Metals.
Metalloids are Brittle, Shiny substances.
They are Semi – Good Conductors of heat and electricity.
Metalloids are known to form Weakly Acidic Oxides.
They have the ability to form Metallic Alloys.

7. MIXTURES
When two or more substances mix with each other
without participating in a chemical change, the resulting
substance is called a Mixture.
The properties of Mixtures are:-
The Components of a Mixture each keep their Original
Properties.
The Separation of Components can be Easily Done.
The Proportion of the Components is Variable.
There are two types of Mixtures:-
• Homogeneous Mixtures – Alloys, Solutions
• Heterogeneous Mixtures – Suspension, Colloids

8. ALLOYS
Alloys are mixtures of two or more metals or a metal and a non-metal and
cannot be separated into their components by physical methods. It is
considered as a mixture because it shows the properties of its constituents
and can have variable composition. An Alloy is Homogeneous Mixture.
For example – Brass, Bronze, Cast Iron, 18K Gold, etc.,

9. TRUE SOLUTIONS
A Solution is a Homogeneous Mixture of two or more
substances. It has a Solvent and a Solute.
Examples: A Solution of Sugar in Water is a Solid in
Liquid Solution.
 A Solution of Iodine in Alcohol known as ‘Tincture of
Iodine’, has iodine as the solute and alcohol as the
solvent.
 Aerated drinks like Soda Water etc., are Gas in Liquid
solutions.
 Air is a mixture of Gas in Gas. It is a Homogeneous
Mixture.

10. PROPERTIES OF SOLUTIONS
The properties of Solutions are:-
The particles of a solution are smaller than 1 nm (10−9meter) in Diameter.
So, they cannot be seen by naked eyes.
 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.
 The solute particles cannot be separated from the mixture by the process of
Filtration. The solute particles do not settle down when left undisturbed, that
is, a solution is Stable.
IMPORTANT – 1. Solvent – The component of the solution that dissolves the
other in it (present in larger amount) is called the Solvent.
2. Solute – The component of the solution that is dissolved in the solvent
(present in lesser quantity) is called the Solute.

11. CLASSIFICATIONS OF SOLUTIONS
There are three types of solutions:-
 Saturated Solution – A Solution that has dissolved as much solute as it is
capable of dissolving, is said to be a Saturated Solution.
 Unsaturated Solution – If the amount of solute contained in a solution is less
than the saturation level, it is called an Unsaturated Solution.
 Supersaturated Solution – A Supersaturated Solution is a solution that contains
more than the maximum amount of solute that is capable of being dissolved at a
given temperature.

12. CONCENTRATION OF A SOLUTION
The Concentration of a Solution is the amount of solute present in a given
amount (mass or volume) of solution, or the amount of solute dissolved in a
given mass or volume of solvent.
 Concentration of the Solution =
Amount of the Solute
Amount of the Solvent
 Solubility – The amount of the solute present in the saturated solution at
this temperature is called its Solubility.

13. TYNDALL EFFECT
The Tyndall Effect is the phenomenon in which the particles in a colloid
scatter the beams of light that are directed at them. It can be observed when
sunlight passes through the canopy of a dense forest. In the forest, mist
contains tiny droplets of water, which act as particles of colloid dispersed in
air.

14. SUSPENSION
The properties of a Suspension are:-
 Suspension is a Heterogeneous Mixture.
 The particles of a suspension can be Seen by the Naked Eye.
The Particles can be separated from the mixture by the process of Filtration.
The solute particles settle down when a suspension is left undisturbed, it is
Unstable.
 The particles of a suspension Scatter a Beam of Light passing through it
and make its path visible.

15. COLLOIDAL SOLUTION
The properties of a Colloidal Solutions are:-
 A Colloid is a Heterogeneous Mixture.
 The Size of Particles of a colloid is too Small to be
individually Seen by Naked Eyes.
 They do not settle down when left undisturbed, it
is Stable.
 They cannot be separated from the mixture by the
process of Filtration.
 Colloids are big enough to Scatter a Beam of
Light passing through it and make its path visible.

16. COMPONENTS OF A COLLOID
The components of a colloidal solution are the Dispersed Phase and the
Dispersion Medium.
 Dispersed Phase – The solute-like component in a colloid is called
Dispersed Phase.
 Dispersion Medium – The component in which the dispersed phase is
suspended is known as the Dispersing Medium.

17. SEPARATION OF COMPONENTS
The Separation of Components can be done using the following techniques:-
 Centrifugation
 Separating Funnel
 Sublimation
 Distillation
 Fractional Distillation
 Chromatography
 Crystallization

18. CENTRIFUGATION
The Principle of Centrifugation is that the denser particles are forced to the
bottom and the lighter particles stay at the top when spun rapidly.
Applications -1. Used in Diagnostic Laboratories for Blood and Urine Tests.
2. Used in Dairies and Home to separate Butter from Cream.
3. Used in Washing Machines to squeeze out Water from Wet
Clothes.

19. SEPARATING FUNNEL
The Principle of Separating Funnel is that immiscible liquids separate out in
layers depending on their densities.
Applications – 1. To separate Mixture of Oil and Water.
2. In the Extraction of Iron from its Ore, the lighter slag is
removed from the top by this method to leave the molten iron at the bottom in
the furnace.

20. SUBLIMATION
Ammonium Chloride changes directly from solid to gaseous state on heating.
So, to separate a mixtures that contain a sublimable volatile component from
a non-sublimable impurity (salt), Sublimation is used. For Example:-
Camphor, Naphthalene, Anthracene, Iodine and Dry Ice.

21. DISTILLATION
Distillation is used for the separation of components of a mixture containing
two miscible liquids that boil without decomposition and have sufficient
difference in their boiling points.

22. FRACTIONAL DISTILLATION
To separate a mixture of two or more miscible
liquids for which the difference in boiling points
is less than 25 K, Fractional Distillation is used.
For Example:- The Separation of Gases from
Air, etc. The apparatus is similar to that for
simple distillation, except that a fractionating
column 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 vapors to cool and condense repeatedly.

23. SEPARATION OF GASES FROM AIR
Air is a Homogeneous Mixture and can be separated by Fractional
Distillation.

24. OBTAINING GASES FROM AIR

25. CHROMATOGRAPHY
The process of separation of components of a mixture is known as
Chromatography. ‘Kroma’ in Greek means ‘Color’.
Applications – 1. To separate Colours in a Dye.
2. To separate Pigments from Natural Colours.
3. To separate Drugs from Blood.

26. CRYSTALLISATION
The Crystallization method is used to purify solids. It is a process that
separates a pure solid in the form of its crystals from a solution.
Applications – 1. Purification of Salt that we get from Sea – Water.
2. Separation of Crystals of Alum from its Impure Sample.

27. PHYSICAL CHANGES VS. CHEMICAL CHANGES
PHYSICAL CHANGES
• Physical change is a Temporary
change.
• In a physical change, no new
substance is formed.
• Physical change is easily
Reversible.
• In a physical change, the
composition of the substance
remains the same despite its
molecules being rearranged.
CHEMICAL CHANGES
• Chemical Change is a Permanent
change.
• In a chemical change a new
substance is formed.
• Chemical changes are Irreversible.
• In a chemical change, molecular
composition of the substance is
changed entirely.
• For Example – Rusting of Iron.

28. THANK
YOU