ÉXPERIMENT L(b)

Preparation of a suspension of soil, chalk powder and fine

sand in water.

MATERIALS REQUIRED
Three boiling tubes (bigger in size), test tube stand, glass rod, a spatula, measuring pipette or
measuring cylinder, smallsample of soil, chalk powder, fine s¡nd and clean water.

THEORY/PRINCIPLE.
A suspension is a heterogeneous mixture of two or more substances. In suspension,
the solute
particles do not dissolve but remain suspended throughout the bulk of the medium. These
particles are visible to the naked eye.
The particle size is greater than 100 nm (10 m). Rays of light cannot pass through suspension.
down due to
On allowing the suspension to stand for a while, the particles of the solute settle
effect of gravity. Hence, a suspension is unstable in nature.
water
When small amount of solid (solute) such as soil, chalk powder and fine sand is added to
(solvent) and stirred, a heterogeneous mixture is obtained which is opaque, unstable and settle
filtration
lb
down after some time. These particles can be separated from the solvent by using
method. 9th
muddy
Some common examples of a suspension are paint dyes suspended in turpentine oil, Class
water, etc.
sCIE
PROCEDURE
1. To prepare suspension of soil Man
" Take a clean boiling tube.
pipette.
" Pour 30 ml of distilled water in it, with the help of a
spatula.
" Add about 1 g of soil in boiling tube with the help of a Lab
some time.
" With the help of glass rod, stir the mixture for
should not be disturbed during
Allow the boiling tube to stand for 5-6 minutes. This solution
the standing time.

21
Shot onOnePlus
 1.
shownin Fig.
Suspension of soil is
The process of preparing a

Spatula
Pipette

Soil Glass rod

-Water
Soil + Water
Soil

Suspension
Dissolving soil of soil
Boiling tube Water poured Adding soil by glass rod
into boiling tube to water
a suspension of soil
Hg. 1 Process of preparing

Observation
Soil particles in boiling tube are clearly visitble.
S2 To prepare suspension of chalk powder
" Take a clean boiling tube.
" Pour 30 mL of distilled water in it, with the help of a pipette.
" Add about 1g of chalk powder inboiling tube with the help of a spatula.
" With the help of glass rod, stir the mixture for some time.
" Allow the boiling tube to stand for 5-6 minutes. This solution should not be disturbed during
the standing time.
The process of preparing a sSuspension of chalk powder is shown in Fig. 2.
1.b
9th
Spatula
Class Pipette

SCIENCE Chalk
powder

-Glass rod
uInua

-chalk powder
+ Water
Boiling tube Water poured
into boilingtube Adding chalk
Dissolving
powder to water
powder chalk
by glass rod Suspension of
Fia. 2 Process of chalk powder in water
Observation preparing a suspension of chalk
powder
Particles of chalk powder in boiling tube are
clearly visible.

22
 sand
Soprepare suspension of fine
" Take a clean boiling tube. pipette.
water in it, with the help of a
" Pour 30 mL of distilled with the help of a spatula.
of fine sand in water in boilingtube
" Add about 1 g time.
help of glass rod, stir the mixture for some
" With the
stand for 5-6 minutes. This solution should not be disturbed during
" Allow the boiling tube to
the standing time. Fia. 3.
preparinga suspension of fine sand is shownin
The process of

Spatula
Pipette

Fine
sand Glass rod

fine sand
+ Water

Dissolving fine Suspension of

Water poured Adding fine fine sand in water
Boiling tube sand to water sand by glass rod
into boiling tube

suspension of fine sand

Fig. 3 Process of preparinga

ebservation
Particles of fine sand in boiling tube are clearly visible.

RESULT
suspension in water in which small solid particles
settled 1b
Soil, chalk powder and fine sand form
down at the bottom of boiling tube. 9th
Class
PRECAUTIONS
the fine powder of chalk. sCIE
While preparingsuspension of chalk thoroughly, take
sieve the ordinary sandthrough muslin cloth so
While preparing suspension of fine sand in water,
as to obtain fine sand.
Stir the contents of the test tube thoroughly. Man

Lab
EXPERIMENT L(C)
solution of starch and caa
Preparation of a colloidal
albumin n weter.

MATERIALS REQUIRED glass, a glass rod, starch, egg albumin,

mL capacity, a watch
Two clean beakers each of 100 and tripod stand.
clean water, Bunsen burner, wire gauze

THEORY/PRINCIPLE The particles of a

heterogeneous mixture, consisting of two or more substances.
A colloid is a particles
uniformly spread throughout the solution.Due to the relatively smaller size of
colloid are homogeneous. But actually, a
compared to that of a suspension, the mixture appears to be
as
colloidal solution is a heterogeneOus mixture.
cm in diameter.
size of the particles of solute in a colloid is in between 10 to 10
The cannot see them with naked eye.
Because of the small size of colloidal particles, we
added to the water and stirred well, the
When small amount of starch or egg albumin are
medium is homogeneous, but cloudy in
solid particles get dispersed in water such that
appearance.
1
PROCEDURE
water
1.Preparation of colloidal solution of starch in
upto about
. Take about 30 mL of distilled water in a beaker (100 mL capacity) and heat it
burner so that water
50°C ina water bath for about 5 minutes. Reduce the flame of the
remainS around 50°C.
like
Take 1 aof starch in a watch glaSS and add a few drops of cold water to make a paste
mass.
. Transfer the paste of starch to hot water with continuous stirring so that no lump formation
takes place.
Stir the contents thoroughly till the paste of starch disappears (Fig. 1).
. Heat the mixture of starch and water for about 10 minutes.
If there are suspended particles (umps), separate them by filtration.
" Collect the filtrate in a clean beaker.

25
Allow the beaker to stand for 5-6 minutes This solution should not be disturbed during
standing time.

Spoon

Beaker
Glass rod

-Water

-Starch

Fig. 1 Preparation of colloidal solution of starch

Observation
About 5 grans of starch dissolve completely in 30 mL of distilled water at particuiar conditon
(temperature and pressure). The solution obtained is translucent and no sediments settie down
at the bottom of the beaker.
 Pbservation
Egg albumindissolves completely in 30 mLofdistilled water at particular condition (termperature
and pressure). The solution that obtained is translucent. Component of colloidal solution cannot
be separated by filtration.

RESULT
Colloidal solutions of starch in water andegg-albumin-in-water are obtairned.

PRECAUTIONS
continued so that no lump formation
While adding starch slurry into warm water, stirring must be
takes place.
water to prevent lump formation.
Dry starch should never be added to warm controlled
albumin, temperature of water should be
While preparing the colloidal solution of egg
(-35°C) properly.
EXPERIMENT L{d)
To distinguish between a true solution, asuspension and a
colloidal solution on the basis of transparency, filtration
and stability.

MATERIALS REQUIRED
Three test tubes, funnel, filter paper, test tube stand, solution of common salt, solution of egg
albumin and solution of chalk powder (already prepared).
AAEORYIPRINCIPLE
Irue solutions are transparent and components of a true solution cannot be separated by
tiltration as particles size are vervy small. In case of a true solution, no sediment settles down,
showing that it is a stable medium. The beam of light passes through the transparent true
solution without scattering.
Suspensions are opaque and components of a suspension can be separated by filtration.
Aresidue is left behind on the filter paper after filtration. Also the beam of light neither pass
through the suspension nor scattered.
Colloids are translucent solution and components of its solution cannot be separated by
filtration. In case of a colloidal solution, no sediment settles down, showing that it is a stable
medium. In this case, the beam of light gets scattered.

PROCEDURE
1d
1. Take three test tubes and label them as A, B and C.
9th
2. Mark each test tube in the lower half witha sign ofcross (x).
3. Place these test tubes on atest tube standsuch that the mark () is on the opposite side of the Class
test tubes.
4, Fill test tube Awith true solution of common salt [Refer experiment 2(a)], test tube Bwith SciENC
Suspension of chalk powder [Refer experiment 2(b)]and test tube Cwith colloidal solution of
eggalbumin in water [Refer experiment 2(c)] [as shown in Fig. 1].
Manua

Labora

Fig. 1 Test tubes containing true solution, a suspension and a colloidal solution

29
 OBSERVATION
Experiment Observation Inference
S.No. Property
1 Transparency Fill half of the test tube A
with The mark (×) is clearly The common salt
Common salt solutioh. Visible when seen solution is transparent,
through the test tube A. and therefore, it is a true
solution.
Fill half of the test tube B with The mark (x) is rnot The suspension of chalk
the suspension of chalk visible when seen powcder is opaque. So, it
through the test tube B. is a suspension.
powder.
Fill half of the test tube C with The mark (x) is faintly The solution of egg
colloidal solution of egg visible when seern alburnin is translucent.
albumin. through the test tube C. So, it is a colloidal
solution.
View through each sample
and record your
observations and
inferences].
Filter the conternts of each In the case of test tube Comrnon salt cannot be
2 Filtration A, a clear filtrate is separated from its
criterion test tube separately through
obtained (in test tube D) solution in water by
a filter paper andcollect the and no residue is left on filtration. So, sample Ais
filtrate in three clean test
tubes. Also label them as D, the filter paper. atrue solution.
E and F respectively.
Observe the filtrate and the
residue left on the filter
paper, if any as shown in
Fig. 2.
In the case of test tube Chalk powder can be
B, aclear filtrate is separated from its
obtained (in test tube E) Suspension in water by
and some residue filtration. So, sample Bis
(chalk powder) is left on a suspension.
the filter paper.
In the case of test tube Egg albumin cannot be
separated from its
C,a translucent filtrate is colloidal solution in
obtained (in test tube F)
water by filtration. So,
d and no residue is left on
the filter paper. sample Cis a colloidal
solution.

True solution of
The contents of test is
Leave the test tubes Common salt in water
Stability tube Ashow no change.
3
(A, B and C) on a test tube
about
stable.
stand undisturbed for
min, andnote your
5observations and inference.
of chalk
The suspension
Bigger particles tend to powder in water is
settle down at the unstable.
bottom of test tube B.
solution of
The colloidal
The contents of test water is
eggalbumin in
tube Cremain stable.
unchanged and no solid
particles settle down.
 Cone of filter paper

Funnel
Funnel

-Residue
D E

Translucent
(cloudy) colloidal -Clear water Clear -Test tube
solution of egg stand
solution
albumin

Clear water collects No residue is left

No residue is left
behind during during filtration of behind during
Suspension of chalk filtration of the solution
filtration of colloidal
powder in water. The of common salt.
solution of egg
albumin in water. residue (chalk powder) is
left behind on filter paper.

Fig. 2 To distinguish between a true solution, a suspension and

a colloidal solutionon the basis of filtration

RESULT
From the experiments performed, the following results are obtained:
1. Common salt solution, ie solution Ais transparent, stable and its components cannot be
separated by filtration.
2. The suspension of chalk powder in water, i.e solution B is opaque, unstable and its
components can be separated by simple filtration.
and its
3. The colloidal solution of egg albumin in water, i.e solution C is translucent, stable
components cannot be separated by simple filtration, 1.d
PRECAUTIONS
9th
Use a laboratory coat while carrying out the experiment. Class
Chalk should be ground well in a mortar by using pèstle to get a fine powder.
tubes.
Use aseparate glass rod for stirring the contents of the different test SCIE
Allthe solutions should be stirred well.

Man

Labo
EXPERIMENT 2
To prepare
() amixture (i) acompound
Using iron filings and sulphur powder and distinguish
between these on the basis of
(a) appearance, i.e. homogeneity and heterogeneity.
(b) behaviour towards a magnet.
(c) behaviour towards carbondisulphide as asolvent.
(d) effect of heat.

MATERIALS REQUIRED
China dish, pestle-mortar, petridish,watch glass, test tubes, glass rod, Bunsen burner, tripod
stand, wire gauze, magnifyingglass, bar magnet, funnel, filter paper, iron filings (10 g),sulphur
powder (5 g), carbon disulphide (5 mL), dilute hydrochloric acid or dilute sulphuric acid.
THEORY/PRINCIPLE
Mixture is a substance containing two or more elements or compounds in any proportion. The
formation of mixture involves a physical change. Hence, the components of a mixture retain
their individual properties. The componernts of a mixture can be separated by physical meáns. 2
The appearance of a mixture can be homogeneous or heterogeneous. The mixture of iron
filings (Fe) and sulphur powder (S) is heterogeneous in appearance. The components can be
present in any proportion and their proportion can be changed. No energy change is involved 9th
in the preparation of a mixture. Class
Examples of mixture are air, sand, salt, iron filing and sulphur, etc. Amixture is not represented
by any chemical formula and it does not have a fixed boiling point. scIENC
Acompound is apure substance which is formed by combination of two or more elements in
definite proportion by mass. It is homogeneous in nature. The formation of a compound
involves a chemical change. Hence, the components of a compound lose their individual
properties and the resulting compound(s) acquire(s) new properties. Manual
The components of a compound cannot be separated by physical means, Examples of
compounds are Common salt, water, etc. Acompound (e.g. iron sulphide, FeS) is represented
bya chemical formula and has a fixed melting and boiling points. Laborat
Jn a mixture of Fe (iron filings) and S (sulphur powder), the iron filings can be
separated by
means of a magnet and sulphur can be separated by dissolving in carbon disulphide (CS ).
However, iron sulphide (FeS) which is a compound, is neither attracted by the magnet nor it
dissolves in carbon disulphide (CS, ).

35
 PROCEDURE sulphur(S) powder mortar
and pestle and
1. Preparation of mixture of iron (Fe)filing a Grind
Keep it asidethe
in
sulphur powder and sulphur.
Take 10g of iron filings and 5 g obtainedis a mixture of iron
powderso
constituents properly. The Fig. 1(a).
in
as Aas shown and
in a China dish and label this mixture
sulphide) of iron filings mixture in sulphur powder
Preparation of a compound (FeS,iniron Heatthe
another China dish. mass is obtained
the China dish
Take one-half portion ofthe mixture black as shown in
with a glass rod, till a
strongBy. stirring continuously black mass COol.
Fig. 1(b). Then stop heating. and let the Heat FeS
Fe(s)+ S(s) Iron (l) sulphide
Iron Sulphur

China dish

Mixture A(Fe+S)
Wire gaUze

China dish China dish

-Burner

Compound B

(a) (b) (c)

Fig. 1 Preparation of FeS
(a) Mixture A (Fe+S)
(b) Mixture A(Fe+S) is heated and becomes black mass B(FeS)
(c) CompOund B[FeS]
Grind the solid black mass in a clean pestle and mortar to a fine powder. Keep it aside in a
.2 China dish. Label the powder of black mass as B as shown in Fig. 1(c).
3. To distinguish between the compound and the mixture
9th Now take required amounts of mixture A and
black mass B to conduct various tests as
Class mentioned in the following table and record your observations and inferences in tabular torm.
OBSERVATION TABLE
SCIENCE
S.No. Test/ Experiment
Property Observation Inference
Appearance Take a small quantity of the
Manual mixtureA prepared in a Grey particles of iron and
yellow The mixture A(Fe +S) is
petridish. Observe it first with particles of sulphur
are seen heterogeneous in appearance
the nakedclearly
the naked eye and then with
a magnitying glass. eye. even with at room temperature.
Laboratory
Take a small quantity of the
Compound B of iron and The whole
sulphur in a petridish. massin appears
uniform black The compound B(FeS) iS
Observe it first with the colour. nomogeneous in appearanoe
naked eye and then with
a magnifying glass.

36
S.No. Test/
Experiment Observation Inference
Property
Behaviour Move a bar magnet over the Iron particles get attracted The component elements of a
towards prepared mixture Aof iron and
magnet towards the magnet and mixture retain their properties.
sulphur. sulphur is left behind. Iron retains its properties in
Bar magnet mixture.
Mixture Aof iron
and sulphur
(Fe+S)
Petridish

Move a bar magnet over the The black coloured Thecomponents forming a
prepared compound B of iron particles of the compound compound lost their properties.
and sulphur. B do not get attracted to Iron has lost its properties of
-Bar magnet the magnet. being attracted by magnet.
Compound B
(FeS) of iron
and sulphur
Petridish

3 Behaviour Take a small quantity of Carbon disulphide (CS,) The components forming a
towards prepared mixture A of iron and dissolves sulphur and iron mixture can be separated by
carbon sulphur in a test tube. Add 1-2particles are left on filter simple physical methods.
disulphide mL of carbon disulphide. paper. Yellow sulphur
(CS,) asa Shake well and filter. Collect crystals can be seen in the
solvent the filtrate in a China dish. Let China dish after carbon
carbon disulphide evaporate. disulphide has evaporated.
Take a small quantity of the The conmpound of iron and Constituents of a compound
prepared compound Bof iron sulphur does not dissolve cannot be separated by simple
and sulphur in a test tube. in carboh disulphide. physical methods.
Add 1-2mL of carbon
disulphide to it and shake
well.

4. Æffect of Take a small quantity of the At higher temperature, iron The components of the mixture
heat prepared mixture A of iron and and sulphur react to form a A iron and sulphur react on
Sulphur in a China dish and black coloured substance
heat it. which does not show the
properties of iron and
heatingto give a compound B
called iron sulphide. 2
sulphur.
Fe(s) + S(s) Heat FeS(s)
Iron sulphide
9th
Take a small quantity of the No reaction occurs. The The compound B (iron sulphide)
prepared compound B of iron substance on strong remains chemically unchanged
Class
andsulphur in a China dish heating, starts glowing and on heating.
and heat it. on cooling, it returns to its sCIEN
original colour.
5 Reaction with Take a small quantity of the Bubbles of a colourless Iron reacts with dilute H,SO, to
prepared mixture A of iron and and odourless gas are give hydrogen gas.
dilute
sulphuric sulphur in aboiling tube. Add evolved which burns with a Fe(s) + H,SO,(aq)’ Manu
acid, H,SO4 1-2 mL of dilute H,SO, and blue flame with a popping FeSO, (aq) + H,(g)
(aq) heat it. Bring burning splinter sound. Yellow powder
near the mouth of the boiling (sulphur) remains
tube. unreacted. Labo
Take a small quantity of the A
gas having the smellof The liberated gas is hydrogen
prepared compound B of iron rotten eggs is evolved. sulphide.
and sulphur in a test tube. FeS+ H,SO,(aq)
Add 1-2 mL of dilute H,SO4: FeSO, (aq) + H,S(g)

37
RESULT mixture'A (Fe +S) is obtained
sulphur powder are mixed together, a
1. When iron filings and obtained.
When this mixture is heated, a compound 'B (FeS) is
shown by mixture A only not by cornpound B
2. Magnetic behaviour towards maanet is nature
nature and compound B is hornogen0us in
3. The mixture A is heterogeneous in
can be separated into its constituent by physical methods
mixture A
X 4. Constituents of
Y compound B cannot be separated out.
(dissolving in CS. ) but constituents of
iron and sulphur (mixture) combine chemically to form FeS. However,
5. On heating strongly,
heat has no effect on compound FeS.
added to mixture Aa colourless and odourless H, gas is obtained which
6. When dil. H, S0, is
is added to compound B, H, S gas with a
burns with pop sound whereas when dil. H, S0,
smell of rotten eggs is obtained.

PRECAUTIONS
ordinary glass tube, as the test tube may crack
Donot heat the mixture of iron and sulphur in an tube to heat the mixture.
boiling
due to strong heating. Use a China dish or a
flammable.
KKeep CS, away from the flame, as it is forceps
bare hands to avoid injury, use
Do not touch the pieces of the black mass(FeS)with
while observing FeS pieces in the experiment.
Donot inhale gases evolved directly.
performing various experiments.
Use asmallamount of the mixture or compound for
EXPERIMENT 3
Toseparate the components of a mixture of sand, common
salt and ammonium chloride (or camphor) by sublimation.

MATERIALS REQUIRED
China dish, glass funnel, tripod stand, burner, test tube, cotton plug, perforated filter paper,
beaker, spatula, wire gauze, distilled water, sand, ammonium chloride/camphor, common
salt and water.

THEORY/PRINCIPLE
The given mixture contains three components: ammonium chloride (or camphor),common salt
andsand. These components differ in their properties as followS:
Ammonium chloride (or camphor) sublimes on heating, whereas there is no effect on
sand and common salt. The process by which asolid directly changes to vapour state
on heating is called sublimation.
Heating
Solid Vapour
Cooling

NH,CI(SOlid)
Ammonium chloride
Heat
Cool
NH,CI (Vapour)
Ammonium chloride 3
So. ammonium chloride is separated from sand and common salt by the process of
sublimation. 9th
Class
Common salt is soluble in water, whereas sand is insoluble in water.
So, common salt can be separated by dissolving it in water and filtering it. The filtrate
salt solution
contains common salt and the residue in the filter paper cone is sand. The SCIENCE
(filtrate) is evaporated when pure common salt is left behind.

Manual

Laborator

43
 Summarisedin Fig.
The scheme of separation is
Mixture Common salt)
Sand +
(Ammonium chloride Sublimation Sand filter
Commonsalt + inwaterand
Dissolve
Sublimate cone
(Ammonium chloride) Residue in titer paper
(Sand)
Filtrate
(Solution of common salt)
Evaporation
Water escapes
intoatrmosphere
Solid sample left behind
(Common salt)
ofseparation
Fig. 1 Scheme

PROCEDURE
following steps:
This experiment can be performed throughthe sublimation
(camphor) by
Step 1. Separation of ammonium chloride
containing common salt, sand andammonium chloride ina
(0 Take atbout 10-15 gofftthe mixture
China dish. (having holes)
() Place this China dish on atripod stand and
cover it with a perforated asbestos
sheet.
(Mi) Place an inverted funnelon the perforated sheet.
(Iv) Plug the openingof the funnel with a cotton plug.
(v) Heat the China dish on a low flame.
condensed on the
(vi) It is observed that vapours of ammonium chloride are formed and get
Cooler sides or inner wallof the funnel (as shown in Fig. 2).
Cotton plug

3 Inverted funnel

Sublimate (Pure
9th ammonium chloride)
Class Perforated
asbestos sheet
SCIENCE

-Mixture
Manual
Wire gauze
Laboratory
Burner

Fia. 2
Separation of ammoniunm chloride by
sublimation
 burner and allow it to cool.
(vi) After fewminutes, put off the deposit of ammonium chloride with
the nelp of a
scrape the white
(vii) Remove the funnel and
China dish.
spatula.
ie. Common salt and sand, areleft behindin the
substances,
(ix) Non-sublimate
common salt and sand
Step 2.Separation of mixture containing common salt and
sand to a beaker.
() Transfer the left over and stir it wellwith a glass rod (see Fig.
3).
of distilled water into the beaker
(i) Add about 20mL
sand remains as such.
(i) Commonsalt dissolves in water while

China dish containing

/common salt and sand
Common salt
+ Sand in water

Filter paper cone

-Sand
Glass rod

-Filtrate (Solution of
Filter Common salt)
Water

Fig. 4 Fltration
salt in water by
Fig. 3Dissolving common + sand mixture
stirring the common salt

glass funnel and place it on a funnel stand.

(iv) Take a clean
then make a tilter paper cone (as shown in Fig. 5). Set this filter
and
(v) Fold the filter paper twice
funnel.
paper cone in the

First fold Second fold Cone

Fig. 5 Folding a filter paper

beaker under the funnel.

(vi) Place a small aglass rod.
Transfer the contents of the beaker into the flter paper cone with the help of
(vii) Fig. 4)
Collect the filtrate in the beaker placed under the funnel (see
(vii)
water on the Sand in the ilter paper cone. Collect this filtrate also in the same
(ix) Soray a little cold
beaker. sand)
the filter paper Cone trom the Tunnel, open it and place the filter paper (having
(x) Remove
in the sun.
dry. Collect it in a plastic pouch.
(xi) After some time, the sand gets
 ^tép 3. Recovery of common salt from filtrate
China dish and heat it
() Transter the commonsalt solution (filtrate) from the beaker into a
jas shown in Fig. 6(a)].

China dish
Common salt solution

Burner Common salt

(a (b)
Fig. 6 Water evaporates to leave behind solid common salt
(i) When the water starts evaporating rapidly, lower the flame.
(ii) Put off the burner when slightly wet residue is left.
(iv) The white residue left behindin the China dish is solidcommon salt [as shown in Fig. 6(b)].
(v) Scrape the common salt with the help ofa spatula and pack it in a plastic pouch.
OBSERVATIONS
1. When the mixture is heated, dense white fumes are seen as the volatile ammonium chloride
sublimes. When its vapours coolat the cooler region of the funnel, the vapours change back
to solid state, and ammonium chloride is again obtained as sublimate. This way, ammonium
chloride is separated from the mixture.
2. Sand particles, which are insoluble in water, collect as residue on the filter paper cone. The
filtrate, containing commonsalt, passes through the filter paper.
3. Common salt, which is soluble in water, can be collected from the filtrate by evaporation of
water.

3 RESULT
() Ammonium chloride is separated from the mixture by sublimation.
(iü) Sand is removed from the mixture of sandand
common salt by
and then by filtration, where sand remain over filter paper anddissolving
9th the mixture in water
Class salt escapes with filtrate.
(iüi) Common salt from the filtrate is separated by
evaporation.
SCIENCE PRECAUTIONS
Heat ammonium chloride gently. Since, it is a volatile
Put a cotton plug carefully so that the
substance.
vapours not escape out.
do
Manual During evaporation, heating should be stopped as
soon as a slightly wet residue is obtained.
Scrape the condensed ammonium chloride from the
inner walls of the funnel carefully.
Handle all hot apparatus carefully.
Laboratory Take care while filtering so that the filter
paper does not tear off.
Sublimation process should be carried out carefully.
While filtering a solution, drop the solution
Wire gauze should be usedwhile heating content along a
glass rod into the funnel.
solution in beaker or in China dish.
Use distilled water only to prepare
solutions.

46
 EXPERIMENT 4
reactions and classify them as
AO carry out the following
physical or chemical changes:
sulphate solution in water
a iron with copper
6 Burning of magnesium in air
Ac) Zinc with dilute sulphuric acid
d) Heating of copper sulphate chloride inthe form of their
et Sodiumsulphate with barium
solutions in water

MATERIALS REQUIRED with clamp,sand paper, thread, stand,

solution, test tubes, stand
Iron nails, copper sulphate burner, tong, watch glass, zinc granules, dilute
sulphuric
test tube stand, magnesium ribbon, barium
hydrated copper sulphate crystals, sodium sulphate solution and
acid, conical flask,
chloride solution.

THEORYIPRINCIPLE

4 Physical Change process in which the chemical composition of the substance

remains
A physical change is a
new substance. A physical change
unchanged, and which does not result in the production of
material. The reactant substance in a
9th involves a change only in the physical properties of the
methods. Hence, a physical change is
Class physical change can be recovered by simple physical
reversible.
SCIENCE
Chemical Change
substance gives rise to new substance(s)
A chemical change is a process in which reactant
reactant substances in a chemical
having different chemicalcomposition and properties. The change is usualy
chemical
Manual change cannot be recovered bysimple physical methods.Hence, a
of bonds in the atoms
irreversible. Achemical change (chemical reaction) involves the breaking products.
between the atoms of A chemical
of reactingsubstances and making of new bonds
Laboratory change is represented by a chemical reaction.
Different types of chemical reactions are as follows:
() Iron (Fe) with copper sulphate (CuSO,)solution
Fe(s) + CuSO4a (ag) FeSO, (aq) + Cu(s)
Iron Ferrous sulphate
Copper sulphate Copper metal (displaced,
(light green) less reactive)
(more reactive) (blue coloured)

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 (i) Burning of magnesium in air
Heat
2Mg(s) + O, (g) Burn with dazzling
2MgO
Magnesium Oxygen Magnesium oxide
(from air) white light (white powder)
(ii) Zinc with dil. sulphuric acid
Zn(s) + H,SO,(aq)
Zinc metal
’ ZnSO,(ag) + H, (g)
Hydrogen
Sulphuric acid Zinc sulphate
gas

Av) Heating of copper sulphate

Heat
CuSO,(Blue)
5H,O(s) ’ Cuso,(s) + 5H,0
(White)
The abOve process is reversed. when water is added to anhydrous copper Sulphate.
CuSO,(s) +5H,0 CuSO, 5H,0s)
(white)
sulphur trioxide gas
On turther heating, anhydrous copper sulphate decomposes to form
and copper oxide.
Heat
CuSO,(s) ’ CuO(s) + SO,(g)
pentahydrate can be given bythe following
Ihe whole change of heating of copper sulphate
equation:
CuO(s) + SO,(g)+5H,0
Heat
CuSO4-5H,O(s) Water
Sulphur
Copper sulphate Copper trioxide
pentahydrate oXide

in the form of their solution in water

Y) Sodium sulphate with barium chloride
Na,SO, (aq) + BaCl, (aq) BaSO,(s) + 2NaCI(aq)
Sodium chloride Barium sulphate
Sodium sulphate Barium chloride

PROCEDURE,OBSERVATION AND INFERENCE

1. Iron with copper sulphate solution
in water
Observation Inference
S.No. Experiment
in a The blue On reaction of iron nail with CuSO,.
Take about 10 mL of CuSO, solution and coloured solution solution, FeSO, is formed which is
and drop a clean
clean, dry test tube test becomes light light green in colour and free Cu is
Keep the
rust free iron nail into it. green in colour. formed which is deposited over the
undisturbed for about 10 min [as
tube iron nail as a reddish brown
shown in Fig. 1(a)]. deposit. This shOWs that iron is
more reactive than copper as Fe+
CuSO, (aq) + FeIron(s) ’
Copper sulphate ions have displaced Cu ions from
FeSO, (aq)+ Cu (s) Displaced
copper sulphate solution.
Ferrous sulphate
copper

The iron nail gets This is an example of chemical

from the solution.
2. Remove the iron nails Coated with a change as in this reaction,colour
blue colour of
Compare the intensity of both test reddish brown change, deposition of residue and
solution of
Copper sulphate compare the colour deposit. the new substances are formed
tubes A and B. Also which have different properties.
with
in CuSO, solution
of iron naildipped 1(b)].
shown in Fig.
kept aside •as

53
 Test tutbe
Stand
Thread
Coppersulphate
solution
Ironnail

(a)

Test tube B
A Iron sulphate
solution (light green)
(after experiment)

Iron nail
Test tube stand
(after experiment)
Iron nail
Copper Sulphate solution (before experiment)
(blue colour)
(before experiment) (b)
solution
dipped in copper sulphate conmpared before and after the experiment
Fig. 1 (a) Iron nails sulphate solution
(b) Iron nails and copper

in air
2. Burning of magnesium Observation
Inference
Experiment Mg burns with O, to
S.No. The magnesium ribbon
and rub it with sand form a new chemical
1 Take a magnesium ribbon burns with a dazzling
one end of about 5 compound, Mg0.
paper to remove rust. Hold white flame to form a
pair of tongs and
cm of magnesium ribbon with a white powder which
other end of the
4 bring a burning burner near the
ribbon (as shown in Fig. 2).
keeps dropping tillthe
ribbon is burning.
2Mg (s) + O, (g) ’ 2MgO (s)
Magnesium oxide
9th Magnesium Oxygen
(white)
MaO is basic in nature.
Class 2 Collect the white pOwder on a watch glass and
The pH paper/red litmus
Since, new substance
add few drops of water. Dipa pH paper or red strip turns blue.
is formed, so it is a
scIENCE litmus strip in the solution.
chemical change.

Magnesium ribbon
Manual
Tong

Watch glass
Laboratory Burner.
Magnesium oxide

Fig. 2 Burning of magnesium ribbon in air

54
3. Zinc with dilute sulphuric acid
Inference
Experiment Observation
which burns with a
Take 2-3 pieces of Zinc reacts with acid Hydrogen gas is produced
granulated zinc in a test producing bubbles of gas pop sound.
tube and to this, add about which burns with a pop sound
Zn(s) + H,SO, (aq) ’ ZnSO,(aq)+ H,T
5 mL of dilute sulphuric when a matchstick is brought Dil.

acid and observe (as near it. change because a new

It is a chemical evolution of gas.
shown in Fig. 3). Substance is formed with the
displaces hydrogen from
Zn being more reactive
dil.H,SO4.

Flame
Fine jet

Ha
-Di. HzSO4

-Zinc pieces

with dilute sulphuric acid

Fig. 3 Granulated zinc

4. Heatingof copper sulphate Inference

S.No.
Experiment
Observation
The crystals turn It forms anhydrous copper
sulphate. 4
1 Take smallamount of white due to loss of CuSO, -5H,0 CuSO, + 5H,0
hydrated copper sulphate water -lb0 AnhydroUs Copper
boiling 5 molecules of Copper sulphate
sulphate Cla
th
SC
Crystals in a hard of crystalisation. pentahydrate
over a as no new
tube and heat it This is a physical change crystals
Fig. regain their
flame fas shown in substance is formed and
of water.
4(a)]. original colour on the addition
regained.
White anhydrous Copper sulphate pentahydrate is
Take anhydrous copper copper sulphate turns
2. boiling
sulphate in another drops blue.
few
tube and add a
is formed and
of water.
Black residue is Black residue of copper oxide
is acidic in
Heat anhydrous copper obtained and a SO, gas is evolved. SO, gas
3 in the
sulphate stronglybring pungent smelling gas nature.
a evolved which turns
250° C CuO + SO,T
boiling tube and paper is CuSO4
moist blue litmusof the blue litmus paper red. New substance is formed,
so it is a chemical
mouth
near the shown in change.
boiling tube fas
Fig. 4(b)].

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 Test tube holder
Test tube holder

Water
droplets -SO, gas
-Boiling tube
Boiling tube
Anhydrous copper.
Hydrated copper sulphate
sulphate crystals -Flame
Flame

-Burner
-Burner
0

Fig. 4 (a) Heating of hydrated copper sulphate crystals

(b) Testing of gas evolved with blue litmus paper
RESULT
a chemical change.
Iron with copper sulphate solution in water is
Burning of magnesium in air is a chemical change.
. Zinc with dilute sulphuric acid is a chemical change. on gentle heating and
become
loses water of crvstallisation
crystallisation
4 The hydrated copper sulphate further heating, it shows chemical change as
physicalchange. On
dirty white, this change is
new substances (CuO and SO)are formed. chloride solution is a chemical change.
sulphate and barium
5. Reaction between sodium
PRECAUTIONS
sand paper.
Clean the iron nal properly by rubbing with touched.
experiment, iron nailcoated with copper should not be
After conmpleting rubbingwith sand paper.
Magnesium ribbon should be clearned by
while burning i
Hold magnesium ribbon using tongs bright flame, students should wear dark glasses.
burns with a dazzling
Since, magnesium ribbon experiment.
granules should be cleaned before conducting the
Zinc
care.
Handle sulphuric acid with it should be handled with care.
poisonous nature. So,
Copper sulphate has a fumes should not be inhaled.
nature, its the
As sulphur trioxide is
acidic in
and sodium sulphate for 5-10 minutes, to allow
barium chloride
not disturb the mixture of down.
precipitate to form and settle