Matter is seen in variety of shape, texture, sizes and colours. The matter has physical and chemical characteristics which defines its category. In this chapter we will study about characteristics of mixtures and its types, how they are different from pure substances, colloids, suspensions and solutions, separation techniques for components of mixtures and their commercial use, physical and chemical changes, metals, non metals and metalloids, elements and compounds.

1. IS MATTER AROUND US PURE?
Pure substances and Mixtures, Types of Mixtures, Solution,
Concentration of Solution, Suspensions, Colloids, Separation
Methods for components of Mixtures, Separating gases of Air,
Crystallization, Physical and Chemical Changes, Types of Pure
substances, Elements and Compounds
Topics to be covered

2. SUBSTANCE
● A substance is a pure single form of matter.
MATTER/SUBSTANCE
PURE
SUBSTANCES
MIXTURES
HETEROGENEOUS
MIXTURES
HOMOGENEOUS
MIXTURES
COMPOUNDSELEMENTS

3. PURE SUBSTANCES
MIXTURES
● When we combine different substances into each other a mixture is formed.
● Mixtures can be separated by physical methods.
● For Example: Lemonade is a mixture of three substances; Lemon Juice, Sugar and
Water.
● Mixtures may be homogeneous mixtures or heterogeneous mixtures.
● A substance that consists of only one type of particle is called a Pure Substance.
● Their chemical properties remains same but physical properties may/may not be
same.
● For Example: Diamond, Salt, Sulfur, Tin.

4. GUESS WHICH IS WHAT?
● Which of these is a mixture or a pure substance?
Water, Copper, Chocolate cake, Hydrogen, Soil, Air
MIXTURES
Chocolate
Cake
Soil
Air
PURE SUBSTANCE
Water
Copper
Hydrogen

5. ● Mixtures in which the components
mix with each other uniformly are
called Homogeneous Mixtures.
● The ratio of compositions of
homogeneous mixtures can be
different.
MIXTURES
HETEROGENEOUS
MIXTURES
HOMOGENEOUS
MIXTURES
● Mixtures in which the components
mix with each other non-uniformly
are called Homogeneous Mixtures.
● They can be separated by physical
means.
MIXTURES

6. MIXTURESMIXTURES
HOMOGENOUS MIXTURES HETEROGENOUS MIXTURES
It has uniform composition. It has non-uniform composition.
The components of mixture cannot be
separated by physical methods.
The components of mixture can be separated
by physical methods.
The size of particles are too small to be seen
through naked eyes.
The size of particles are big enough to be seen
through naked eyes.
There is no boundary between components of
mixture.
Clear boundary can be seen between
components of the mixture.
For example: salt solution, sugar solution,
lemonade
For example: Oil in water, sand in water

7. HETEROGENOUS MIXTURE
MIXTURESHOMOGENOUS MIXTURE
LIQUID IN LIQUID GAS IN LIQUIDSOLID IN LIQUID
Muddy/sand water
SUSPENSION COLLOIDS
Milk
SOLUTION
Sugar/salt in water Soft drinksMilk and water

8. ACTIVITY 2.1
500 mL water + one spoon
CuSO4
500 mL water + two
spoons CuSO4
KMnO4 + CuSO4
A B C D
Activity: The class is divided into 4 groups; A,B,C and D. The materials are provided to the groups, asked to mix them and
observe uniformity in colour.
Group A added 1 spoon of copper sulphate in 500 mL water, Group B added 2 spoons of copper sulphate in 500 mL water,
Group C mix 2 spoons of KMnO4 and 1 spoon of CuSO4 and Group D mix 1 spoon of KMnO4 and 2 spoons of CuSO4
Conclusion: Group A and B made uniform solution of copper sulphate despite the amount of salt added. Group C and D made
non uniform mixture. Hence A and B group made homogenous mixture and C and D made heterogenous mixture.
KMnO4 + CuSO4

9. ACTIVITY 2.2
500 mL water + few
crystals of CuSO4
500 mL water + one
spoon of CuSO4
C DA B
Activity: The class is divided into 4 groups; A,B,C and D. The materials are provided to the groups, asked to mix them. Observe
the beam of light through the beaker and filter the mixture to check for residue.
Group A added few crystals of copper sulphate in 500 mL water, Group B added 1 spoon of copper sulphate in 500 mL water,
Group C mix 2 spoons of chalk in 500 mL of water and Group D mix few drops of ink in 500 mL of water.
500 mL water + chalk
powder
500 mL water +
few drops of
milk/ink

10. ACTIVITY 2.2
C DA B
Observation: 1) When a beam of light is passed through the solution, the path of light is visible in C and B. This means the light
is scattered by the particles of chalk and ink in C and D. This effect is called Tyndall effect.
2) The residue is observed in C only. This means the particles of chalk do not dissolve properly.
Conclusion: Based on the observation, A and B is solution, C is suspension and D is colloid.

11. HOMOGENOUS MIXTURE: SOLUTIONS
● Solution is a homogenous mixture of two or more substances.
● A solution has two components:
○ Solvent : The component of solution (usually in larger amount) dissolve
another component of solution in it.
○ Solute : The component of solution (usually in less amount) get dissolved in
the solvent.
● The particles of solution cannot be seen through naked eyes. The size of particles are as
small as 1 nanometer in diameter.
● The particles of solution do not scatter light hence doesn’t show tyndall effect
(Phenomenon in which path of light is visible).
● The components of solution cannot be separated through filtration method.
● The solution is stable and solute particles do not settle when left undisturbed.
● Example: salt solution, sugar solution, tincture of iodine, aerated drinks and air.

12. TYPES OF SOLUTION
CONCENTRATION OF SOLUTION
METHODS TO CALCULATE
CONCENTRATION OF
SOLUTION
DILUTE SOLUTION
CONCENTRATED SOLUTION
UNSATURATED SOLUTION
SATURATED SOLUTION
SUPERSATURATED SOLUTION
The concentration of solution amount of
solute present in a given amount
(mass/volume) of the solution.
OR
The amount of solute dissolved in a given
mass or volume of solvent
The amount of the solute present in the
saturated solution at a given temperature is
called solubility.

13. Dilute Solution
● A dilute solution is one that has a
relatively small amount of dissolved
solute.
TYPES OF SOLUTIONS
Concentrated Solution
● A concentrated solution is one that has
a relatively large amount of dissolved
solute.

14. Unsaturated Solution
TYPES OF SOLUTIONS
Saturated Solution
Supersaturated Solution
A solution, in which we can add more amount of
solute as it has not achieved its saturation level
yet, is called an Unsaturated Solution. A dilute
solution can be called as an Unsaturated Solution.
A solution in which no more solute can be added
since it has already dissolved the maximum
amount of solute it can is called a Saturated
Solution.
A solution that contains more than the maximum
amount of solute that is capable of being
dissolved at a given temperature is called
Supersaturated Solution.

15. ● One way to describe the concentration of a solution is by the percent of the solution that is
composed of the solute.
● This percentage can be determined in one of three ways:
(1) the mass of the solute divided by the mass of solution x 100 (Percentage by mass)
(2) the volume of the solute divided by the volume of the solution x 100 (Percentage by
volume)
(3) the mass of the solute divided by the volume of the solution x 100
Percentage by mass = Mass of solute
------------------- x 100
Mass of solution
Percentage by volume = Volume of solute
--
-------------------- x 100
Volume of solution
Mass by Volume percent = Mass of solute
--
----------------- x 100
Volume of solution
METHODS TO CALCULATE CONCENTRATION OF SOLUTION

16. Q: What is the percentage concentration of a solution is prepared from 10 g NaCl in enough water to
make a 150mL solution?
Ans: mass of solute = 10g
mass of solution = 150 mL
Q: A solution contains 40 g of common salt in 320 g of water. Calculate the concentration in
terms of mass by mass percentage of the solution?
Ans: mass of solute = 40g
mass of solvent = 320 g
mass of solution = mass of solute + mass of solvent
= 40 + 320 = 360 g
Percentage by mass = Mass of solute
------------------- x 100
Mass of solution
Mass by Volume percent = Mass of solute
--
----------------- x 100
Volume of solution
= 10
---- x 100 = 6.7 %
150
LET’S PRACTICE
= 40
---- x 100 = 11.1 %
360

17. ALLOYS
● An alloy is homogeneous mixture of two or more metals or a metal and non-metal
which cannot be separated by physical methods.
● It shows the properties of its constituents and can have variable composition.
BRASS (Copper and Zinc)
BRONZE (Copper and Tin)
SOLDER (Tin and Lead)
STEEL (Iron and Carbon)
AMALGAM
(Mercury and other
metals like gold,
silver, tin
STAINLESS
STEEL (Iron
,Carbon, Nickel
and Chromium)

18. HETEROGENOUS MIXTURE: SUSPENSIONS AND COLLOIDS
● A suspension is a heterogeneous
mixture in which solute particles
do not dissolve but remain
suspended throughout the
medium.
● A colloid is a heterogeneous
mixture in which solute particles
uniformly spread throughout the
medium.

19. HETEROGENOUS MIXTURE: SUSPENSIONS
● A suspension is is a heterogeneous mixture in which solute particles do not dissolve but
remain suspended throughout the medium.
● The particles of solution can be seen through naked eyes. The size of particles are
greater than 100 nanometer in diameter.
● The particles of solution scatter light hence show tyndall effect (Phenomenon in which
path of light is visible).
● The components of solution can be separated through filtration method.
● The solution is unstable and solute particles settle at the bottom when left undisturbed.
● Example: mixture of chalk and water, smoke in air.

20. HETEROGENOUS MIXTURE: COLLOIDS
● A colloid is a heterogeneous mixture in which solute particles uniformly spread throughout
the medium.
● Components of colloidal solution:
○ Dispersed Phase : The solute like component present in lesser amount.
○ Dispersed Medium: The component of solution in which dispersed phase is
suspended
● The particles of solution can be seen through naked eyes. The size of particles are ranges
between 1 nanometer to 1000 nanometer in diameter.
● The particles of solution scatter light hence show tyndall effect (Phenomenon in which path
of light is visible).
● The components of solution cannot be separated through filtration method.
● The solution is stable and solute particles do not settle at the bottom when left undisturbed.
● Example: Milk, Cheese, Clouds, Shaving cream, Face cream, Butter, Mud, Foam, etc.

21. HETEROGENOUS MIXTURE: COLLOIDS

22. METHODS TO SEPARATE COMPONENTS OF MIXTURE
SIMPLE PHYSICAL METHODS COMPLEX PHYSICAL METHODS
FILTRATION
SIEVING
HAND PICKING
EVAPORATION
CENTRIFUGATION
SUBLIMATION
CHROMATOGRAPHY
DISTILLATION

23. SIMPLE PHYSICAL METHODS
FILTRATION
SIEVINGHAND PICKING

24. COMPLEX PHYSICAL METHODS
EVAPORATION
CENTRIFUGATION
SUBLIMATION
CHROMATOGRAPHY
DISTILLATION

25. SEPARATION OF COLOURED COMPONENT (DYE) FROM BLUE/BLACK INK
PROCEDURE:
a. Fill the beaker half with water and put the watch glass on the mouth of the beaker
b. Put a few drops of ink on the watch glass and start heating the beaker.
c. Continue heating till no change is observed on the watch glass.
d. Stop heating and observe.
OBSERVATIONS:
There is a patch of dye on the watch glass.
CONCLUSIONS:
The ink is composed of volatile component (water) from non-volatile solute (dye). On heating
the volatile component evaporated and non-volatile left behind.

26. SEPARATION OF CREAM FROM MILK: CENTRIFUGATION
PROCEDURE:
a. Take full cream milk in a test tube.
b. Centrifuge the milk in centrifuge machine for 2 minutes.
If not available, use churner in the kitchen.
c. Note your observations.
OBSERVATIONS:
The cream is developed on the surface.

27. APPLICATIONS OF CENTRIFUGATION
a. Used in diagnostic laboratories for blood and urine tests.
b. Used in dairies and home to separate butter from cream.
c. Used in washing machine to squeeze out water from wet clothes.
CONCLUSIONS:
The fat component (cream) is less dense than other component of the milk. Based on the
density gradient, the denser particles are forced to settle at the bottom and the lighter
particles stay at the top on centrifugation. The component which settle at the bottom is
called pellet while liquid part is called supernatant.This process in which heavy particles
settle down is called sedimentation.

28. SEPARATION OF TWO IMMISCIBLE LIQUIDS
Principle:
The immiscible liquids can be separated in layers based on
difference in their densities.
Activity:
a. Pour the mixture of kerosene oil and water in a separating
funnel.
b. Let it stand undisturbed for sometime so a distinct boundary can
be seen.
c. Open the stopcock of the separating funnel and pour out the
lower layer of water carefully.
d. Close the stopcock of separating funnel as the oil reaches the
stop-cock.

29. SEPARATION OF MIXTURE USING SUBLIMATION
Principle:
The sublimable volatile component changes from solid into vapour
directly on heating.
● Take some mixture of salt and camphor or ammonium
chloride in a china dish.
● Put an inverted funnel over the china dish.
● Put a cotton plug on the stem of funnel.
● Heat slowly and observe.
Observation:
The camphor turns into vapor state without entering into the liquid
state. This process is called sublimation.
Some examples of solids which can sublime: Ammonium chloride, Camphor, Naphthalene
and Anthracene.

30. SEPARATION OF DYE IN BLACK INK: CHROMATOGRAPHY
Principle:
The solute that has more solubility will travel faster in
chromatography paper.
Activity:
● Take thin strip of filter paper. Draw a line
approximately 3 cm above the lower edge.
● Put a small drop of ink (water soluble). Let it dry.
● Lower the filter paper into a glass jar containing
water so that drop of ink is just above the water level.
● Watch carefully and record your observations.
Observations:
Different colors will be obtained in a vertical column as water rises in the filter paper.

31. SEPARATION OF DYE IN BLACK INK: CHROMATOGRAPHY
Inference:
● Ink is mixture of two or more colors. The solute particles that is more soluble in water
will travel faster upward.
This process of separation based on the solubility of
particles of dye is called chromatography. The word
“Kroma” means Color in greek.
Types of Chromatography:
a) Paper Chromatography
b) Thin Layer Chromatography (TLC)
c) Gel Chromatography
d) Column Chromatography
e) Ion-Exchange Chromatography
f) Gel Filtration Chromatography
g) Gas Liquid Chromatography
h) Affinity Chromatography

32. APPLICATIONS OF CHROMATOGRAPHY
a. Separation of dyes.
b. Separation of pigments from natural colors.
c. Separation of drugs from blood.
SEPARATION OF TWO MISCIBLE LIQUIDS: DISTILLATION
Activity:
a. Take the mixture of acetone and water in a
distillation flask fitted with thermometer.
b. Arrange the apparatus as shown in figure.
c. Heat the mixture slowly keeping a close watch at
thermometer.

33. Observations:
The acetone vaporises, condenses in the condenser and can be collected in beaker.
Water is left behind in the distillation flask.
SEPARATION OF TWO MISCIBLE LIQUIDS: DISTILLATION
This process of separation of components of a mixture containing two miscible
liquids having difference in their boiling point is called Distillation.
FRACTIONAL DISTILLATION
● If the difference in boiling points of miscible liquids
is less than 25 K, fractional distillation is used.
● Separation of petroleum products and gases of air are
examples.
● Glass beads are used in fractionating column to cool
the vapors by providing surface area.

34. Air is homogeneous mixture and its components can be separated by fractional
distillation.
SEPARATION OF GASES FROM AIR
Air
Liquid Air
Compress and cool by increasing and decreasing temperature
Oxygen Argon Nitrogen
Boiling Point {oC} -183 -186 -196
% by volume 20.9 0.9 78.1
Allow to warm up slowly in fractional distillation column. Gases
gets separated at different heights

35. SEPARATION OF GASES FROM AIR

36. OBTAINING PURE SUBSTANCE FROM IMPURE SAMPLE: CRYSTALLISATION
Activity:
● Take some impure copper sulphate sample in
china dish.
● Dissolve it in minimum amount of water. Filter
the impurities out.Add few drops of dilute
sulphuric acid.
● Evaporate water to make a saturated solution.
Cover it with watch glass and leave it
undisturbed overnight.
Observations:
Crystals of copper sulphate are formed in the china dish.
The process of obtaining pure substances in the form if crystals from their impure solution is
called crystallisation.

37. OBTAINING PURE SUBSTANCE FROM IMPURE SAMPLE: CRYSTALLISATION
Advantages over simple evaporation technique:
● Some solids decompose, like sugar, may be charred on heating to dryness.
● Some impurities may remain dissolved in the solution even after filtration. It will
contaminate the solid.
Applications:
● Purification of salt that we get from sea water.
● Separation of crystals of alum, phitkari from impure samples.

38. WATER PURIFICATION SYSTEM

39. PHYSICAL AND CHEMICAL CHANGES
PHYSICAL PROPERTIES
COLOUR
HARDNESS
RIGIDITY
FLUIDITY
DENSITY
MELTING
POINT
BOILING POINT
● Interconversion of states of states without change in
composition or chemical characteristics is called
Physical Change.
● Interconversion of states which involve change in
composition or chemical characteristics is Chemical
Change.
● Burning of Candle is both Physical and Chemical
change. In this melting of wax is physical change but
burning of wick of candle is a chemical change.

40. PURE SUBSTANCES: ELEMENTS
● Robert Boyle used term “element” in 1661.
● Antoine Laurent Lavoisier define element experimentally. According to him, it is
defined as a basic form of matter that cannot be broken down into simpler substances
by chemical reactions.
METALS NON-METALS METALLOIDS
● Lustrous
● Good heat and
electrical conductivity
● Malleable and ductile
● Sonorous
● Non-lustrous
● Poor heat and
electrical conductivity
● Non- Malleable and
Non-ductile
● Non-sonorous
● Exhibit properties of
both metals and non-
metals

41. PURE SUBSTANCES: COMPOUNDS
● Pure substances composed of two or more elements chemically combined with one
another in fixed proportion.
● Composition of compound is same throughout.
● The chemical properties of compound is different than its constituents.
EXCEPTIONS IN METALS AND NON-METALS
● Liquid metal: Mercury
● Soft metals: Potassium, Sodium, Cesium, Gallium
● Lustrous non-metal: Graphite (carbon) and Iodine
● Liquid non-metal: Bromine
● Good conductor of electricity non-metal: Graphite
● Non-malleable metal: Zinc

42. Observations:
● No reaction takes place in china dish A.
● On heating till red hot, the colour and texture of materials changed in china dish B.
ACTIVITY 2.10
Activity:
● Take some iron filings and mix with sulphur powder in china dish named A.
● Take some iron filings and mix with sulphur powder in china dish named B and heat
it strongly till red hot. Remove from flame and let it cool.
● Note the observations.
Inferences:
● In china dish A, physical change is observed.
● In china dish B, chemical change is observed.

43. Observations:
● Iron filings get attracted towards magnet in china dish A.
● Sulphur powder appear yellowish while iron filings appear dark grey/brown in china dish B. Sulphur
powder is smooth while iron filings are brittle.
● There will be no change takes place in either of the china dish.
● In china dish A, a colourless, odourless but combustible gas {hydrogen} is formed. Candle
extinguishes with POP sound. In china dish B, a colourless gas with rotten eggs smell is released.
ACTIVITY 2.10 PART II
Activity:
● Take mixture of china dish A and B & check for magnetism by bringing a magnet near the materials.
● Compare the colour and texture of china dish A and B.
● Observe china dish A and B while testing with carbon disulphide. Stir well and filter the contents.
● Observe the reaction in china dish A and B with dilute sulphuric acid or hydrochloric acid. Place a
burning candle near the chine dish A and B
Inferences:
● In china dish A, materials are elements.
● In china dish B, materials combined chemically to form compound name iron sulphide.

44. ELEMENTS VS COMPOUNDS
Made up of only one type of atoms.
May be made up of same or different types
of atoms.
Cannot be broken down into its constituents
by physical or chemical means.
Constituents can be separated by suitable
chemical means.
Properties remain same Properties of constituents are lost
Represented by symbols. Eg: Fe (Iron) Represented by formula. Eg: H2O (Water)