Unit-IV; Professional Sales Representative (PSR).pptx
Is matter around us pure
1. Is Matter around us Pure?
By
N.Aarthi,B.E.,M.Tech
SASTRA
Chapter-2
2. What is a Mixture?
• Mixtures contains more than one kind of pure
form of matter.
• Dissolved sodium chloride can be separated
from water by evaporation.
• But sodium chloride is pure substance and
cannot be separated into sodium and chlorine
separately.
3. Types of Mixtures
Based on composition of substance which form a
mixture Mixtures can be divided into 2 types
• Homogeneous- Mixtures which have uniform
composition throughout.
Example: salt solution in water, sugar solution
• Heterogeneous- Mixtures do not have uniform
composition.
Example: mixture of sand and water, mixture of
sodium chloride and iron fillings.
7. Mixtures can be divided into 3 types on basis of
composition and size of their particles.
1. Solutions
2. Suspensions
3. Colloidal solutions
8. Solutions
• A homogeneous mixture of two or more
substances is called solution.
• Example: Lemonade, soda water, sugar and water.
• Homogeneity in a solution is at particle level.
• Salt or sugar solution in water tastes same
throughout.
• Solutions may be solid, liquid ,or gas.
• Solid solution: Alloys
• Gaseous solution: Air( oxygen 21%, nitrogen 78%)
10. Composition of a solution
A solution is made of solvent and solute as its component.
Solvent
• The component of the solution that dissolves the other
component in it is called solvent.
• The component of a solution present in larger amount is
called the solvent.
Solute
• The component of the solution that is dissolved in the
solvent is called the solute.
• The component of a solution present in smaller amount is
generally called solute.
Example: In a salt solution in water. Water is solvent as it is
present in larger amount and salt is solute as salt is present in
smaller amount.
12. Solid-solid Solution
When both the component in a solution are solids,
then solution is called solid-solid solution.
For Example: alloys.
Alloys
• An alloy is made by mixing of two more solids.
These solids may be metals or non-metals. Alloys
are the Examples of solid solution.
Example: Brass: Brass is a mixture of about 30% of
zinc and 70% of copper.
Stainless steel: Stainless steel is an alloy of steel and
with a minimum of 10.5% of chromium.
13. Gas-Gas Solution
When both of the components of a solution are
gas, then solution is called Gas-Gas Solution.
For Example: Air.
Air
• Air consists of many gases. Air consists of
mainly oxygen, carbon dioxide and nitrogen
and other many gases. Hence air is
an Example of gaseous solution.
14. Solid-Liquid Solution
Tincture of Iodine
• Tincture of iodine is an Example of solution.
Tincture of iodine is a homogeneous mixture of
iodine and alcohol. In this solution, iodine is
solute as it is present in smaller amount and
alcohol is solvent as it is present in larger amount.
• Thus tincture of iodine and salt solution in water
are the Example of solid-liquid solution.
• Salt solution in water, sugar solution in water, etc.
are the Examples of solid liquid solutions.
16. Gas-Liquid Solution
• When one component of a solution is gas and
other is liquid, then solution is called gas
liquid solution.
• Aerated drinks like soda water etc,
are Examples of gas in liquid solution.
18. Properties of a Solution
• A solution is a homogeneous mixture.
• The particles of a solution are smaller than 1 nm(10–9 metre) in
diameter. Since particles of a solution are very small in size,
thus they cannot be seen by naked eyes.
• A beam of light is not scattered when passed through a
solution. This is because particles of solution are very small,
i.e. microscopic in size, hence they do not scatter the beam of
light. And hence path of light is not visible in a solution.
• The solute particles of a solution cannot be separated through
the process of filtration.
• The solute particles of a solution do not settle down when left
undisturbed. This is the cause that a solution is stable.
19. Concentration of a solution
Depending on the amount of solute present in a
solution it can be called
Dilute
Concentrated
Saturated/Unsaturated solution
20. Saturated Solution
• 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,
then the solution is called SATURATED
SOLUTION.
22. Unsaturated Solution
• If the amount of solute contained in a solution is
less than the saturated level, it is called an
UNSATURATED SOLUTION.
• In other words, if the amount of solute contained
in a solution is less than the capacity of
dissolving, the solution is said to be Unsaturated
Solution.
Solubility:
• The amount of solute present in a saturated
solution at a given temperature is called the
SOLUBILITY of the solution.
24. Dilute and Concentrated Solution
• Dilute and concentrated are the relative or comparative terms.
• The relative proportion of the solute and solvent can be varied.
• Concentration of a solution depends upon the amount of solute
present in a solution. A solution can be called dilute,
concentrated or saturated depending upon the amount of solute
present in a solution.
• If there are two same solutions, and one solution contains less
amount of solute than other, then solution which has larger
amount of solute will be called concentrated and that which has
lesser amount of solute will be called dilute solution.
• If we take a salt solution in water. Put it in two test tubes. And
mix some water in one test tube, then this solution will be called
dilute and that one in which water has not been added will be
called concentrated solution.
25. Concentration of A Solution
• The amount of solute present in a given
amount of solution, or the amount of solute
dissolved in a given mass or volume of
solvent, is called CONCENTRATION.
26. • Mass by mass % of a solution
= mass of solute *100
mass of solution
Mass by volume % of a solution
= mass of solute *100
volume of solution
Volume by volume % of a solution
= volume of solute *100
volume of solution
27.
28. What is a suspension?
• Heterogeneous mixture in which solute
particles do not dissolve but remain
suspended throughout the medium.
• Particles are visible to naked eye.
• Example: mixing chalk powder in water.
30. Properties of a suspension
• Heterogeneous mixture.
• Particles seen with naked eye
• Particles scatter beam of light, path is visible.
• Solute particles settle down when left
undisturbed.
• Suspension is unstable. Can be separated by
filtration.
• When particles settles, suspension breaks and
does not scatter light anymore.
31. What is a colloidal solution?
• Particles are uniformly spread in the solution.
• Mixture appears to be homogeneous.
• But colloidal solution is heterogeneous.
• Example: Few drops of milk or ink in water.
• Particles are small in size. Cannot be seen in
naked eye.
• Particles easily scatter beam of light .
• This scattering of light is called Tyndall effect.
33. Properties of a Colloid
• Heterogeneous mixture.
• Particles too small.
• Scatters beam of light.
• Particles do not settle down. So it is stable.
• Particles cannot be separated from mixture by
filtration.
• Technique called centrifugation can be used to
separate colloidal particles.
34.
35. Components of colloidal solution
• Solute like component forms dispersed phase
• Component in which dispersed phase is suspended is
known as dispersing medium.
• Example:
36. Separating the components of a mixture
How can we obtain colored dye from blue/black
ink?
Activity asks us to heat the solution of ink and
water.
37. Observation:
• On heating the solution, water evaporates,
and we get back the ink dye in the watch
glass.
Explanation:
• The different substance has a different boiling
point. We use this property to separate the
components of the mixture. Here, the boiling
point of ink is much higher than that of water.
On heating the ink solution, water evaporates
while ink dye remains in the china dish.
38. Application:
• Crude petroleum refinery: Crude Petrol
obtained from the earth contains a mixture of
various petroleum products like petrol, diesel,
LNG, vaseline etc. All these components have
a different boiling point. This difference helps
us in separating them.
• Separation of metals from its alloys in
metallurgical industries.
• Preparation of milk powder/khoya from milk.
39. How can we separate cream from milk?
Activity asks us to separate cream from the milk
by centrifugation.
40. • Container is spun at very high speed.
• Cream gets separated and floats on top .
• Milk is left at bottom.
We can separate components of a mixture by
centrifugation if the components of the mixture have
different densities.
41. Application:
• Separation of components from the blood in
pathological testing.
• Preparation of butter from the milk.
• Used in washing machines to squeeze out
water from wet clothes.
42. How can we separate a mixture of two
immiscible liquids?
Aim
Separate kerosene from the mixture of
water and kerosene using separator
43. What is separator?
A separator is a simple instrument to ease the
process of separation. It has an opening at the
top. We pour the liquid mixture from this
opening and let it settle for a few minutes using
a stand. After a few minutes, immiscible liquids
form separate layers, which we filter out one by
one.
44. A separator is a funnel-like apparatus. It can be
used to separate immiscible liquids.
Observation:
• Water is heavier and sinks at the bottom. When
we open the stopcock, the water separates out
from the kerosene.
Explanation/Principle:
• An immiscible liquid is a mixture of two or more
liquids which do not mix with each other. For
example, all types of cooking oil are immiscible
with the water. In case of immiscible liquid
heavier liquid settle at the bottom and the lighter
liquid floats on the top.
45. How can we separate a mixture of salt and
camphor?
46. • Camphor changes directly from solid state to
gaseous state on heating.
• Sublimation process is used to separate
sublimable volatile component from non-
sublimable impurity.
• Examples: ammonium chloride, naphthalene,
anthracene.
47. Is the dye in black ink a single color?
Activity asks us to separate the ink dye from the
paper using chromatography technique.
48. • Take thin strip of filter paper
• Draw line on it using pencil 3cm above lower
edge.
• Put small drop of ink at center of the line.
• Lower the filter paper into glass jar containing
water.
• Watch carefully, water rises up on filter paper.
49. Chromatography
Some facts:
Water rises in the paper due to
capillary action. The force of attraction
between the paper and water is more
than between two water molecules. It
creates a pulling pressure on the water.
It results in the rise of water.
We use it in separating components of volatile
oils to make expensive perfumes, separate drugs
from blood.
50. Observation:
• The dye moves upwards and separates into
different colours.
Explanation:
• An ink dye consists of several colours. These
different dyes have different solubility. Dye with
higher solubility in water dissolves quickly and
move fast with the water. As a result component
of the dye separate with each other.
Inference/conclusion:
• When components of a mixture have varying
solubility, we can separate them using
chromatography.
51. How can we separate a mixture of two
miscible liquids?
Activity asks us to separate a mixture of acetone and
water using the distillation method.
52. Observation:
• Acetone is a volatile liquid. It easily vaporizes on
heating. On cooling, acetone again converts into its
liquid form. Here we receive pure acetone in the
beaker.
Explanation:
• The distillation is the separation of two or more
components from the mixture for volatile compounds.
In this method, we employ the difference in the boiling
point of different compounds. A compound with low
boiling point evaporates fast. We collect these volatile
compounds using condenser.
• With the thermometer, we control the temperature so
that we receive only one compound in the condenser.
53. • This is a costly method as it requires
enormous water to cool the condenser and
costly setup. We use it only in the separation
of precious products like the perfume
industry, petroleum refinery, some distilled
beverage, in treating water salinity.
Facts about acetone:
• Acetone is a colourless organic compound. We
use it in the lab to clean lab equipment as it
dissolves many chemicals. We can see its use
as a nail polish remover in daily life.
54. Fractional distillation
It is a tube packed with glass beads. The beads
provide surface for vapors to cool and condense
57. How can we obtain pure copper sulphate
from impure sample?
• Take impure sample of copper sulphate.
• Dissolve it in water.
• Filter impurities.
• Evaporate water from copper sulphate solution.
• Cover the solution with filter paper and leave it
undisturbed at room temperature.
• We will get crystals of copper sulphate in china dish.
• This process is called crystallisation.
58. • Here we heat a solution of copper sulphate.
Heating produces a saturated solution of the
salt. When this solution cool, oversaturation
results in the formation of copper sulphate
crystals. Molecules of a crystal do not contain
any impurity. As a result, we get pure copper
sulphate.
59. Crystallisation
• Crystallisation is a property of some salts. In an over-
saturated solution of the salt, molecules of salt join
to form small clusters. These small clusters have a fix
molecular arrangement. We call such clusters as
crystals.
60. Crystallisation technique is better than
evaporation. Why?
• Some solids decompose or get charred on heating to
dryness. Example: sugar.
• Some impurities may remain dissolved in solution
even after filtration. On evaporation these
contaminate the solid.
Applications:
1. Purification of salt that we get from sea water.
2. Separation of crystals of alum from impure
samples.
61. Physical and chemical changes
• Color, hardness, rigidity, fluidity, density,
melting point, boiling point are physical
properties.
• Both water and oil are liquid but chemical
characteristics are different.
• Oil burns in air but water extinguishes fire.
• Chemical change brings change in chemical
properties of matter and we get new
substances.
62. What are the types of pure substances?
• Pure substances are substances that are made up
of only one kind of particles and has a fixed or
constant structure.
• Pure substances are further classified as elements
and compounds.
63. Element Definition:
• Elements – Elements constitute the simplest
chemical substances in which all the atoms
are exactly the same.
Compound Definition:
• Compounds – Compounds are chemical
substances made up of two or more elements
that are chemically bound together in a fixed
ratio.
64. Elements
• An element is a substance that consists of only
one type or kind of atom.
• An element is a pure substance as it cannot be
broken down or transformed into a new
substance even by using some physical or
chemical means.
• Elements are mostly metals, non-metals or
metalloids.
65. Types of Elements
• The elements are arranged in the periodic
table and are split depending upon their
groups as either metallic or non-metallic.
• Metallic is further classified into Main Group
Metals, Transition Metals, and f-block metals.
• These are again further divided, depending
upon their properties.
66. Examples of Elements
• Elements exist in their simplest form and
cannot be broken down further. So, elements
can exist in the form of ions, atoms, isotopes,
molecules.
• An example of an element is Nitrogen
atom(N), Nitrogen gas (N2), Nitrogen ion(N3-)
and Nitrogen isotopes (Nitrogen-13, Nitrogen-
14, and Nitrogen-15).
70. Metals-Properties
• They have lusture
• Silvery grey or golden color
• Conducts electricity
• Ductile in nature.(wires)
• Malleable(thin sheets)
• Sonorous(ringing sound)
Example: gold, silver, copper, iron, sodium,
potassium.
Mercury is only metal in liquid state at room
temperature.
72. Non metals properties
• They display variety of colors.
• They are poor conductors of heat and
electricity.
• They are not lustrous, sonorous or malleable.
• Example: hydrogen, oxygen, iodine, carbon,
bromine, chlorine.
• Metalloids- both metal and non metal.
• example: boron, silicon, germanium
74. Compounds
• Compounds, on the other hand, are also pure
substances when two or more elements are
combined chemically in a fixed ratio.
• However, these substances can be broken
down into separate elements by chemical
methods.
76. Types Of Compounds
• Compounds can be classified into two types,
molecular compounds and salts. In molecular
compounds, the atom binds each other
through covalent bonds. In salts, it is held
together with ionic bonds. These are the two
types of bonds out of which every compound
is made of.
77. A covalent bond is formed by equal
sharing of electrons from both the
participating atoms
78. Ionic bond also called electrovalent bond, type of linkage formed
from the electrostatic attraction between oppositely
charged ions in a chemical compound.
79. Example Of Compounds
• Example of compounds includes water
(H2O), Hydrogen Peroxide (H2O2), etc. You
could see water’s chemical formula, it says it
has 2 atoms of Hydrogen combined with 1
atom of oxygen and in hydrogen peroxide, it
has 2 atoms of hydrogen and two atoms of
oxygen.
• Similarly, an example of salt would be the
table salt (NaCl) which has 1 atom of sodium
and one atom of chlorine.
80. Characteristics and Properties Of Pure
Substances
• Pure substances are mostly homogeneous in
nature containing only one type of atoms or
molecules.
• These substances mainly have a constant or
uniform composition throughout.
• The substances have fixed boiling and melting
points.
• A pure substance usually participates in a
chemical reaction to form predictable products.
81. Examples of Pure Substances
• All elements are mostly pure substances. A
few of them include gold, copper, oxygen,
chlorine, diamond, etc. Compounds such as
water, salt or crystals, baking soda amongst
others are also grouped as pure substances.
82.
83. Activity :Heat iron with sulphur and see their
magnetic and chemical behaviour.
Observation/finding:
• Iron forms iron sulphide on heating with
sulphur.
• Iron sulphide does not show the magnetic
property.
• Addition of carbon disulphide to iron sulphide
does not have any change.
• Iron sulphide reacts with dilute acid and
produces hydrogen gas.
84. Explanation:
• This experiment wants us to understand the
difference between a mixture and a
compound.
• A mixture formation is a physical
phenomenon which does not include any
chemical reaction.
• When two elements or molecules react and
from product different from the reactant, the
product is called a compound.
85. • Here, the mixing of iron filings with sulphur does
not cause any reaction. They are a mixture.
• When we heat both the substance, they react
with each other and form iron sulphide. This is a
compound formation.
• During this chemical reaction free electrons in the
outer shell (valance shell) of iron form covalent
bonds with the electrons of sulphur. Free
electrons are necessary for magnetic property. As
a result, iron sulphide does not show magnetic
property like iron.
• Metal salts react with acids and displace the
hydrogen atom. This produces hydrogen gas.
86.
87. Extra Questions
List the points of differences between homogeneous
and heterogeneous mixtures.
Answer:
88. How are sol, solution and suspension different from
each other?
Answer:
89. To make a saturated solution, 36 g of sodium chloride
is dissolved in 100 g of water at 293 K. Find its
concentration at this temperature.
Answer: Mass of solute (sodium chloride) = 36 g
Mass of solvent (water) = 100 g
Mass of solution = Mass of solute + Mass of solvent
= 36 g + 100 g = 136 g
90. How will you separate a mixture containing kerosene and
petrol (difference in their boiling points is more than 25°C),
which are miscible with each other?
Answer: A mixture of kerosene and petrol which are miscible
with each other can be separated by distillation.
Method
• Take a mixture in a distillation flask.
• Fit it with a thermometer.
• Arrange the apparatus as shown in the figure.
• Heat the mixture slowly.
• Petrol vaporises first as it has lower boiling point. It condenses
in the condenser and is collected from the condenser outlet.
• Kerosene is left behind in the distillation flask.
91. Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt.
Answer: (i) Centrifugation,
(ii) Evaporation,
(iii) Sublimation.
What type of mixtures are separated by the technique
of crystallisation?
Answer: Crystallisation technique is used to purify solid
with some impurities in it. Example: Salt from sea-
water.
93. Try segregating the things around you as pure
substances or mixtures
Answer: Pure substances—Water, bread, sugar and
gold.
Mixtures—Steel, plastic, paper, talc, milk and air.
