CHEMISTRY PRACTICAL
CLASS – IX
Objective:
Preparation of:
a.)a true solution of common salt,sugar and alum.
b.)a suspension of soil,chalk powder and fine sand in water.
c.)a colloidal solution of starch in water and egg albumin/ milk in water and
distinction between these on the basis of
* transparency
*filtration criterion
*stability
Fundamentals:
True Solution: A true solution is one in which the solute particles cannot be
distinguished from the solvent even with the help of microscope. It is
homogeneous in composition and contains one phase only .The solute particles are
less than 10-9 metre diameter.
Suspension: In a suspension, the solute remain suspended in solvent and slowly
settles down under the effect of gravity .The solute particles are greater than 10 -6
metre in diameter.
Colloid: A colloid contains relatively large particles, called the dispersed
phase,distributed throughout a solvent like medium, called the continuous phase or
the dispersing medium .The size of colloidal particles is between 10 -9 – 10-6 metre.
Apparatus / Materials Required:
Common salt, Sugar, Alum powder , soil, Chalk powder,fine sand, beakers, glass
rod , distilled water, starch powder, egg albumin / milk, filter paper ,funnel, conical
flask etc.
Observation:
S.No. Test for True solution Suspension Colloidal
solution
1. Transparency The solution is The solution is The solution is
completely opaque translucent.
transparent ie the
solute and solvent
particles cannot be
distinguished from
each other
2. Filtration No residue is left Particles of No residue is left
on the filter paper chalk, sand etc on the filter paper
and a clear filtrate are visible on the and a translucent
is obtained. filter paper and filtrate is
the filtrate is obtained.
clear water
3. Stability The particles of The suspended The particles of
solute present in particles in the the solute present
the solution do not solution settle in the solution do
separate out on down after some not separate out
keeping time. on keeping
undisturbed. undisturbed
Precautions:
*Wash all the apparatus ie beakers, conical flasks, glass rods, etc with distilled
water before starting the experiment.
*Use separate filter paper for each solution.
*The ends of the glass rods should be smooth.
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Experiment :2
Objective:
Preparation of :
a.)a mixture
b.) a compound
using iron filings and sulphur powder and distinction between these on the basis of:
i.)appearance , ie, homogeneity and heterogeneity
ii.)behavior towards a magnet.
iiI)behavior towards carbon disulphide as a solvent
iv.)effect of heat
Fundamentals:
Mixture:A mixture contains more than one substance . A mixture can be separated
by physical means into two or more substances. Also a mixture has a variable
composition.
Compound:A compound is a substance composed of two or more elements
chemically combined with one another. A pure compound, always contains
definite or constant proportions of the elements by mass.
Apparatus / Material Required:
Iron filings 5g, sulphur 3g,carbon disulphide solution , magnet, burner,tripod
stand, wire gauze, china dish, test tubes, glass rod, beakers etc.
Observations:
1.Appearance
2.Behaviour towards a Magnet
3.Behaviour towards carbon disulphide
4.Effect of heat
Precautions:
*The mixture of iron and sulphur should be heated in a hard glass test tube.
*Carbon disulphide should not be brought near a flame, because it is inflammable.
*The mixture of iron and sulphur should be heated strongly.
Experiment:3
Objectives:
Performing the following reactions and classifying them as physical or chemical
changes:
a.)Iron with copper sulphate solution in water.
b.)burning of magnesium ribbon in air.
c.)Zinc with dilute sulphuric acid
d.)heating of copper sulphate crystals
c.)Sodium sulphate with barium chloride in the form of their solutions in water.
Fundamentals:
I. Iron with copper sulphate solution in water:
When iron metals comes in contact with aqueous copper sulphate, Fe 2+ ions
displace Cu2+ ions and ferrous sulphate is formed.
Fe +Cu2+SO4→Fe2+SO4 + Cu
II. Burning of magnesium ribbon in air
When burnt in air ,it combines with oxygen to form its oxide.
2 Mg + O2 → 2 MgO
This reaction is a direct combination reaction and the change is chemical.
III. Zinc with dilute sulphuric acid:
When zinc comes in contact with dilute sulphuric acid the following chemical
reaction takes place .
Zn + H2SO4 →ZnSO4 + H2
This reaction is a displacement reaction and the change is chemical.
IV. Heating of copper sulphate crystals:
When heated up to a temperature of 250ₒC, hydrated copper sulphate decomposes
to form anhydrous copper sulphate which is white in colour.
CuSO4.5H2O →CuSO4 + 5 H2O
This reaction is a decomposition reaction and the change is physical .On adding
Water to anhydrous copper sulphate it regains its blue colour and becomes
hydrated.
V. Sodium sulphate solution with barium chloride solution
When these solutions are mixed a white precipitate of barium sulphate is formed
and the following chemical reaction takes place:
Na2SO4 +BaCl2 →BaSO4 + 2NaCl
This reaction is a double displacement reaction and the change is chemical.
Apparatus / material required:
Iron nails, copper sulphate solution, magnesium ribbon, zinc granules, dilute
sulphuric acid, copper sulphate, sodium sulphate solution, barium chloride
solution, a pair of tongs , china dish, test tubes, tripod stand, burner, wire gauze,
beaker, glass rod ,water, etc.
PART:I
Iron with copper sulphate solution in water:
Observation and Conclusion:
The reaction which takes place is :
Fe(s) +CuSO4 (aq) → FeSO4 (aq) +Cu(s)
This is a displacement reaction. Iron being more reactive then copper diasplaces
copper from copper sulphate solution.
Thus ,iron nails turn from grey to brown in colour and the copper sulphate solution
changes colour from blue to light green.
The reaction between iron and copper sulphate solution is a chemical change
because new substance are formed as a result of the reaction.
PART- II
BURNING OF MAGNESIUM RIBBON IN AIR
Observation and Conclusion:
The reaction which takes place is
2Mg + O2 → 2MgO
This is a direct combination reaction.
Thus magnesium ribbon burns with a white dazzling flame and changes into a
white substance which is magnesium oxide.
Burning of magnesium in air is a chemical change because a new substance is
formed as a result of the reaction.
PART- III
ZINC WITH DILUTE SULPHURIC ACID
Observation and Conclusion:
The reaction which takes place is
Zn+H2SO4 →ZnSO4 + H2
This is a displacement reaction. Zinc being more active metal , displaces hydrogen
from a solution of sulphuric acid.
Thus bubbles are formed in the solution and a colourless and odourless gas is
evolved which burns with a pop sound when a burning splinter is brought near the
mouth of the test tube.
PART- IV
HEATING OF COPPER SULPHATE CRYSTALS
The reaction which takes place is
CuSo4.5H2O→ CuSO4 +5 H2O
On cooling the white powder of anhydrous copper sulphate regains water
molecules from atmosphere and again turns blue.
CuSo4+ 5H2O→CuSO4.5H2O
Heating of copper sulphate is a physical change because no new substance is
formed as a result of the reaction.
PART-V
SODIUM SULPHATE WITH BARIUM CHLORIDE IN THE FORM OF
THEIR SOLUTION IN WATER
Observation and conclusion:
The reaction which takes place is
Na2 SO4 + BaCl2 →BaSO4 + 2 NaCl
This is a double displacement reaction. Here So 4 ions displaces Cl- ions and Cl-
ions displaces SO4 ions.
Thus a white precipate of barium sulphate is formed which settles down at the
bottom of the beaker.
The reaction between sodium sulphate and barium chloride is a chemical change
because new substances are formed as a result of the reaction.
Precautions:
Test tubes ,glass rod etc should be clean and dry.
For heating purpose always hard glass test tubes should be used.
Experiment :5
Objective:
Determination of the melting point of ice and the boiling point of water.
Fundamental:
The process during which a solid changes into a liquid on heating is called
melting and the temperature at which this process takes place is called the melting
point of the substance.
Melting point of a substance is defined as the temperature at which both the
solid and liquid forms of the substance exist together in equilibrium, under
atmospheric pressure.
The temperature at which pure water boils to form steam is called its boiling
point.
Boiling point of a substance is defined as the constant temperature at which both
the liquid and vapour forms of the substance exist together in equilibrium under
atmospheric pressure.
Apparatus / materials required:
A glass beaker ,a round bottomed flask, a cork with two bores ,a thermometer, an
iron stand, a Bunsen burner, tripod stand, wire gauze, a glass tube bent at right
angle, crushed ice, pure water etc.
PART- I
DETERMINATION OF THE MELTING POINT:
OBSERVATION
Reading of the thermometer when temperature of melting ice remains
constant=0oC
Result: Melting point of ice = 00c
Conclusion : Melting point of ice is 0 0c and at this temperature both ice and water
exist together.
PART – II
DETERMINATION OF THE BOILING POINT OF WATER
OBSERVATION:
Reading of the thermometer when temperature of boiling water remains constant=
100oC
Result: Boiling point of water = 1000 C
Conclusion: Boiling point of water is 100 oC and at this temperature both water and
steam exist together.
Precaution:
The bulb of the thermometer and the open end of the glass tube should be well
above the water level in the flask.
Record the temperature carefully when it remains constant for about 5 minutes.
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Experiment :6
Objective:
Verification of the law of conservation of mass in a chemical reaction.
Fundamentals:
A change in which the chemical composition of the substance is changed is called
a chemical change. Chemical change brings a change in chemical properties and
thus is called a chemical reaction.
Apparatus/ Materials Required:
Sodium sulphate , barium chloride, distilled water, glass beaker, glass rod ,a
physical balance, watch glasses, weight box, a measuring cylinder, etc.
Observation:
Mass of Na2So4 solution = mass of Na2SO4.10H2O + mass of 100ml of
distilled water
= 16.1g +100g = 116.1g
Mass of BaCl2 solution = mass of BaCl 2.2H2O + mass of 100 ml of distilled
water
= 7.2 g +100g = 107.2g
Mass of reactant = mass of Na2So4 solution + mass of BaCl2 solution
= 116.1 g +107.2g = 223.3g
Mass of products = mass of beaker with contents – mass of empty
beaker
= mc- me
= 223.3g
Precautions:
The apparatus used in the experiment should be clean and dry.
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