ix class 2nd chapte
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CHAPTERCHAPTER--IS MATTER AROUND USIS MATTER AROUND USPUREPURE
CLASSCLASS --IX CIX C
CHEMISTRYCHEMISTRY
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MATTER
PURE SUBSTANCESFIXED COMPOSITION
MIXTURES-NO FIXED COMPOSITION
ELEMENTS-
CANT BEBROKENDOWN
COMPOUNDS-
CAN BE BROKEN
METALS NON METALS METALLOIDS
HOMOGENOUS UNIFORMCOMPOSITION
HETEROGENOUS NON
UNIFORM COMPOSITION
TRUE SOLUTION-PARTICLE SIZE LESSTHAN 1 nm
Colloids-
particle size
1-100nm
SUSPENSIONSSIZE GREATERTHAN 100 nm
MIXTURESCOMPONENTS OF A MIXTURE
CAN BE SEPARATEDBY VARIOUS TECHNIQUES
EVAPORATION
CENTRIFUGATION
SEPARATING FUNNEL
CHROMATOGRAPHY
SIMPLE & FRACTIONAL
DISTILLATIONCRYSTALLISATION
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PURE SUBSTANCEPURE SUBSTANCE
Hasa composition that cannot be altered byHasa composition that cannot be altered byphysical means.physical means.
Substance that consist ofsingle type of particles.Substance that consist ofsingle type of particles.
All constituent particles ofthatsubstance areAll constituent particles ofthatsubstance aresame in their chemical nature or hasa definitesame in their chemical nature or hasa definiteset of properties.set of properties.
All elementsand compoundsare pureAll elementsand compoundsare puresubstances.substances.
For exampleFor example--Water, sugar, sodium, methaneWater, sugar, sodium, methane
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MIXTUREMIXTURE
DEFINITIONDEFINITION--------MIXTUREMIXTURE isa combination oftwo orisa combination oftwo ormore substancesthatare not chemically united and domore substancesthatare not chemically united and donot existin fixed proportionsto each other.not existin fixed proportionsto each other.
CHARACTERISTICSCHARACTERISTICS Components mixed in any proportionComponents mixed in any proportion
Showsthe properties ofits constituentsShowsthe properties ofits constituents
No energy change involvedNo energy change involved
Components ofa mixture can be separated by physicalComponents ofa mixture can be separated by physicalmeanslike Filtration, distillation and chromatography.meanslike Filtration, distillation and chromatography.
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MIXTURESMIXTURES TWO KINDS OF MIXTURESTWO KINDS OF MIXTURES
A)A) Homogenous mixturesHomogenous mixtures same uniform appearance and compositionsame uniform appearance and compositionthroughoutits mass.throughoutits mass.
--components dontshowany visible boundariescomponents dontshowany visible boundaries
ExamplesExamples Saltwater.Saltwater.a dilute solution ofhydrochloric acida dilute solution ofhydrochloric acidwinewine
B)B) Heterogeneous MixturesHeterogeneous Mixtures: do not have uniform composition: do not have uniform compositionthroughout its mass,throughout its mass,
-- components show visible boundaries.components show visible boundaries.
examplesexamples-- sandy watersandy watercarbonated beverage or beer (the CO2 gascarbonated beverage or beer (the CO2 gasis mixed withthe liquid)is mixed withthe liquid)orange juice with pulp in itorange juice with pulp in itwater withice cubesin itwater withice cubesin itchicken noodle soupchicken noodle soup
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SOLUTIONSOLUTION
--Hasasolventand asolute asitsHasasolventand asolute asitscomponentscomponents
SolventSolvent--component presentin largercomponent presentin larger
quantityquantitySoluteSolute-- Component presentin lesserComponent presentin lesserquantity.quantity.
Solid solutions (alloy), GaseoussolutionsSolid solutions (alloy), Gaseoussolutions(Air)(Air)
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WHY IS AN ALLOYWHY IS AN ALLOY
CONSIDERED AS ACONSIDERED AS AHOMOGENOUS MIXTURE?HOMOGENOUS MIXTURE?
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TYNDALL EFFECTTYNDALL EFFECT
Visible scattering oflightalong theVisible scattering oflightalong thepath of beam throughasystempath of beam throughasystem
containing discontinuities by colloidcontaining discontinuities by colloid,suspension.,suspension.
Named after a British physicist JohnNamed after a British physicist JohnTyndall.Tyndall.
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SOLUTIONS,SUSPENSIONS AND COLLOIDSSOLUTIONS,SUSPENSIONS AND COLLOIDS
PROPERTIESPROPERTIES SOLUTIONSOLUTION SUSPENSIONSUSPENSION CCOLLOIDSOLLOIDS
Particle sizeParticle size Less than 1nmLess than 1nm Greater thanGreater than100nm100nm
Size between 1Size between 1to 100nmto 100nm
NatureNature HomogenousHomogenousmixturemixture
HeterogenousHeterogenousmixturesmixtures
Appear to beAppear to behomogenoushomogenous
but actuallybut actuallyheterogenousheterogenous
TyndallTyndallEffectEffect
Do not showDo not showTyndall effectTyndall effect
May or may notMay or may notshow Tyndallshow Tyndalleffecteffect
Will showWill showTyndall effectTyndall effect
StabilityStabilitySolutions areSolutions arestablestable
SuspensionsSuspensions
settle down whensettle down whenleft standingleft standingundisturbed,soundisturbed,sounstableunstable
ColloidalColloidal
dispersions dodispersions donot settle if leftnot settle if leftundisturbed for aundisturbed for along time, hencelong time, henceunstableunstable
Separation ofSeparation of
ComponensComponens
Components cantComponents cant
be separated bybe separated bythe processthe process
Filtration can beFiltration can be
used to separateused to separatethe componentsthe components
Cant be separatedCant be separated
by the process ofby the process offiltration.centrifufiltration.centrifu
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CONCENTRATION OF A SOLUTIONCONCENTRATION OF A SOLUTION
TheThe concentrationconcentration of a chemicalof a chemical solutionsolution refers to therefers to theamount ofamount ofsolutesolute that is dissolved in athat is dissolved in a solventsolvent..
We normally think of a solute as a solid that is added to aWe normally think of a solute as a solid that is added to asolvent (e.g., adding table salt to water), but the solutesolvent (e.g., adding table salt to water), but the solutecould just as easily exist in another phase. For example, ifcould just as easily exist in another phase. For example, if
we add a small amount of ethanol to water, then thewe add a small amount of ethanol to water, then theethanol is the solute and the water is the solvent.ethanol is the solute and the water is the solvent.
Dilute SolutionDilute Solution:Hasasmallamount ofsolute in:Hasasmallamount ofsolute inthe solvent.the solvent.
Concentrated SolutionConcentrated Solution:Hasalarge amount of:Hasalarge amount ofsolute in the solvent.solute in the solvent.-- For ex; 1 tablespoon of salt in 2 cups water is more diluteFor ex; 1 tablespoon of salt in 2 cups water is more dilute
than 3 tablespoons in 2 cups waterthan 3 tablespoons in 2 cups water
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How To Calculate Concentration OfHow To Calculate Concentration Of
a Solutiona Solution
1 Mass by mass percentage of a solution1 Mass by mass percentage of a solution
==mass of solute x 100mass of solute x 100
mass of solutionmass of solution
22 Mass by Volume percentage of a solutionMass by Volume percentage of a solution== mass of solute x100mass of solute x100
volume of solutionvolume of solution
-- MassMass--volume percentage is often used forvolume percentage is often used forsolutions made from asolid solute dissolved in asolutions made from asolid solute dissolved in aliquid.liquid.
-- For exampleFor example, a 40% w/v sugar solution contains, a 40% w/v sugar solution contains40 g ofsugar per 100 mL of resulting solution.40 g ofsugar per 100 mL of resulting solution.
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SOLUBILITYSOLUBILITY
TheThe solubilitysolubility ofasolute isthe maximum quantityofasolute isthe maximum quantity
ofsolute that can dissolve in a certain quantity ofofsolute that can dissolve in a certain quantity ofsolvent or quantity ofsolution ataspecifiedsolvent or quantity ofsolution ataspecified
temperature.temperature.
FACTORS AFFECTING SOLUBILITY
11 nature of the solute and solventnature of the solute and solvent --While only 1 gram ofleadWhile only 1 gram oflead(II) chloride can be dissolved in 100 grams ofwater at room(II) chloride can be dissolved in 100 grams ofwater at roomtemperature, 200 grams of zinc chloride can be dissolved.temperature, 200 grams of zinc chloride can be dissolved.
22 temperaturetemperature ---- Generally, an increase in the temperature ofGenerally, an increase in the temperature ofthe solution increasesthe solubility ofasolid solute. For allthe solution increasesthe solubility ofasolid solute. For all
gases, solubility decreasesasthe temperature ofthe solutiongases, solubility decreasesasthe temperature ofthe solutionrises.rises.
33PPressureressure --Increase in pressure increasesIncrease in pressure increasessolubilitysolubility
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SATURATED SOLUTIONSATURATED SOLUTION
A solution that has dissolved asA solution that has dissolved asmuch solute as it is capable ofmuch solute as it is capable ofdissolving at a particulardissolving at a particulartemperaturetemperature..
oror
When no more solute can beWhen no more solute can bedissolved in a particular solutiondissolved in a particular solutionat a particular temperatureat a particular temperature..
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Saturated, Unsaturated andSaturated, Unsaturated and
Supersaturated solutionSupersaturated solution
Saturated solutionSaturated solution--AA solution that can hold nosolution that can hold nomore ofthe solute ata particular temperature ismore ofthe solute ata particular temperature issaid to be asaturatedsaid to be asaturated solution atthatsolution atthattemperature.temperature.
unsaturated solutionunsaturated solution isasolution, whichisasolution, whichcontainslessamount ofsolute than is required tocontainslessamount ofsolute than is required tosaturate itsaturate it atthattemperature.atthattemperature.
Supersaturated SolutionSupersaturated Solution asolution thatisasolution thatismore concentrated than asaturated solution ismore concentrated than asaturated solution isknown assuper saturated solution. Ifaknown assuper saturated solution. Ifa crystalcrystalofsolute isadded to thissolution, the excess ofofsolute isadded to thissolution, the excess ofsolute crystallizes.solute crystallizes.
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EXAMPLES OF COLLOIDSEXAMPLES OF COLLOIDS
DISPERSEDDISPERSEDPHASEPHASE
DISPERSINGDISPERSINGMEDIUMMEDIUM
TYPETYPE EXAMPLEEXAMPLE
LIQUIDLIQUID GASGAS AEROSOLAEROSOL FOG,CLOUDSFOG,CLOUDS
SOLIDSOLID GASGAS AEROSOLAEROSOL SMOKESMOKE
GASGAS LIQUIDLIQUID FOAMFOAM SHAVINGSHAVINGCREAMCREAM
LIQUIDLIQUID LIQUIDLIQUID EMULSIONEMULSION MILK,FACEMILK,FACECREAMCREAM
SOLIDSOLID LIQUIDLIQUID SOLSOL MILK OMILK OMAGNESIAMAGNESIA
LIQUIDLIQUID SOLIDSOLID GELGEL CHEESE,BUTTER CHEESE,BUTTER
SOLIDSOLID SOLIDSOLID SOLID SOLSOLID SOL MILKY GLASSMILKY GLASS
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SEPARATING COMPONENTS OF A MIXTURESEPARATING COMPONENTS OF A MIXTURE
1 Technique for the separation ofVolatile component from non1 Technique for the separation ofVolatile component from non-- volatilevolatile
componentcomponent--------------------------EVAPORATIONEVAPORATION
2 Technique used for the separation of denser particles from lighter2 Technique used for the separation of denser particles from lighterparticlesparticles--------------------------------CENTRIFUGATIONCENTRIFUGATION
3 Technique for the separation oftwo immiscible liquids based on3 Technique for the separation oftwo immiscible liquids based on
difference in their densitiesdifference in their densities--------SEPARATING FUNNELSEPARATING FUNNEL
4 Technique for the separation of Sublimable from the non4 Technique for the separation of Sublimable from the non--sublimablesublimablecomponentcomponent------------------SUBLIMATIONSUBLIMATION
5 Technique for the separation ofsolutesthat dissolve in the same5 Technique for the separation ofsolutesthat dissolve in the same
solventsolvent----------------------------------------------------CHROMATOGRAPHYCHROMATOGRAPHY6 Technique for the separation oftwo or more miscible liquids.6 Technique for the separation oftwo or more miscible liquids. ------
--------------------------------------------------------------------------DISTILLAION(SIMPLE ANDDISTILLAION(SIMPLE AND
FRACTIONAL DSTILLATION)FRACTIONAL DSTILLATION)
77 Technique for separation of pure compound from impure sampleTechnique for separation of pure compound from impure sample
----------------------------------------------------------------------------CRYSTALLISATIONCRYSTALLISATION
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SEPARATING FUNNELSEPARATING FUNNEL
KEROSINE OIL
WATER
STOP COCK
PRINCIPLE- SEPARATION BASEDON DIFFERENCE IN THEDENSITIES OF TWO IMMISCIBLELIQUIDS
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SUBLIMATIONSUBLIMATION
PRINCIPLE-SEPARATION OFSUBLIMABLE COMPONENT FROMNON- SUBLIMABLE COMPONENT
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PAPER CHROMATOGRAPHY
PRINCIPLE- SEPARATION OF COMPONENTS THAT DISSOLVE IN
THE SAME SOLVENT
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CHROMATOGRAPHY-SEPARATION OF MIXTUREPIGMENTS OF CHOROPLAST
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DISTILLATIONDISTILLATION SEPARATION OF COMPONENTS BY REPEATEDSEPARATION OF COMPONENTS BY REPEATED
HEATING,BOILING AND CONDENSATIONHEATING,BOILING AND CONDENSATION
SIMPLE DISTILLATIONSIMPLE DISTILLATIONPrinciplePrinciple--Separation of a mixture of two miscibleSeparation of a mixture of two miscible
liquids that boil without decomposition and haveliquids that boil without decomposition and havesufficient difference in their boiling points.sufficient difference in their boiling points.
FRACTIONAL DISTILLATIONFRACTIONAL DISTILLATION
PrinciplePrinciple--separation of a mixture of two or more miscibleseparation of a mixture of two or more miscible
liquids having difference in Boiling points less than 25Kliquids having difference in Boiling points less than 25K
For ex.For ex.--MIXTURE OF ETHANOL AND WATER(BOILINGMIXTURE OF ETHANOL AND WATER(BOILINGPOINT OF ETHANOLPOINT OF ETHANOL--78.4 C)78.4 C)
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SIMPLE DISTILLATION
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FRACTIONAL DISTILLATION
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CRYSTALLISATIONCRYSTALLISATION
Technique used to purify soilds from an impure sampleTechnique used to purify soilds from an impure sample
The solution iswarmed in an open container,The solution iswarmed in an open container,allowing the solventto evaporate, leaving asaturatedallowing the solventto evaporate, leaving asaturatedsolution.solution.
A solution whichhasas muchsolid dissolved in itA solution whichhasas muchsolid dissolved in itasit can possibly contain, is called aasit can possibly contain, is called asaturated solutionsaturated solution..
Asthe saturated solution isallowed to cool,Asthe saturated solution isallowed to cool,the solid will come out ofthe solution and crystalswillstartthe solid will come out ofthe solution and crystalswillstart
to grow.to grow.The crystals can then be collected and allowed to dry.The crystals can then be collected and allowed to dry.
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HOW IS CRYSTALLISATIONHOW IS CRYSTALLISATIONBETTER THAN EVAPORATION?BETTER THAN EVAPORATION?
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QUESTION ANSWERSQUESTION ANSWERS
QUESQUES--How can you prove that Air is a mixture?How can you prove that Air is a mixture? Answer:Answer: a) The composition ofair is variable. The composition varies from place to place anda) The composition ofair is variable. The composition varies from place to place and
withaltitude. For instance, athigher altitudes, there isless oxygen in the air. In industrialareas,withaltitude. For instance, athigher altitudes, there isless oxygen in the air. In industrialareas,due to the waste gases coming out ofindustrial chimneysin the form ofsmoke more impuritiesaredue to the waste gases coming out ofindustrial chimneysin the form ofsmoke more impuritiesareadded in the air.added in the air.
b) Air has no definite set of properties. Its propertiesare an average ofits constituents. For e.g.,b) Air has no definite set of properties. Its propertiesare an average ofits constituents. For e.g.,vapour density of oxygen is 16, vapour density of nitrogen is 14 and vapour density ofair is 14.4vapour density of oxygen is 16, vapour density of nitrogen is 14 and vapour density ofair is 14.4
c) The components ofair can be separated by physical means. Fractional distillation ofliquid air canc) The components ofair can be separated by physical means. Fractional distillation ofliquid air canseparat2 and O2. Boiling point ofaliquid N2 =separat2 and O2. Boiling point ofaliquid N2 = --1960 C, Boiling point ofaliquid O2 =1960 C, Boiling point ofaliquid O2 = --1830 C1830 C
d) The formation ofair does notinvolve any energy change. No energy is released or absorbedd) The formation ofair does notinvolve any energy change. No energy is released or absorbedwhen the constituents ofair are mixed in the right proportion. e) Air cannot be assigned a fixedwhen the constituents ofair are mixed in the right proportion. e) Air cannot be assigned a fixedchemical formula.chemical formula.
Question:Question: Classify the following as element, compound or mixture.i) Zinc amalgam (ii) SeawaterClassify the following as element, compound or mixture.i) Zinc amalgam (ii) Seawater(iii) Iodine vapour (iv) Gold coin (v) Water.(iii) Iodine vapour (iv) Gold coin (v) Water.
Answer:Answer: i) Mixturei) Mixture
ii) Mixtureii) Mixture
iii) Elementiii) Element
iv) Mixtureiv) Mixture
v) Compound.v) Compound.
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uest on answersuest on answers
QUESTIONQUESTION Howwill you separate a mixture of NH4ClHowwill you separate a mixture of NH4Cl
and I2?and I2?
ANSWERANSWER--:: Heating cannotseparate the mixture, as bothHeating cannotseparate the mixture, as bothsubstancessublime on heating.However, when water isadded tosubstancessublime on heating.However, when water isadded tothe mixture, NH4Cl dissolves but I2 does not. The mixture is filtered.the mixture, NH4Cl dissolves but I2 does not. The mixture is filtered.The filtrate isasolution of NH4Cl, while the residue isiodine. TheThe filtrate isasolution of NH4Cl, while the residue isiodine. Thefiltrate isheated to obtain NH4Cl crystals.filtrate isheated to obtain NH4Cl crystals.
3 Question3 Question:: Give one example for each ofthe following mixtures:Give one example for each ofthe following mixtures:i) Solid/solid (homogeneous) ii) Solid/solid (heterogeneous) iii)i) Solid/solid (homogeneous) ii) Solid/solid (heterogeneous) iii)Liquid/liquid (homogeneous) iv) Liquid/liquid (heterogeneous) v)Liquid/liquid (homogeneous) iv) Liquid/liquid (heterogeneous) v)Gas/liquid (homogeneous).Gas/liquid (homogeneous).
ANSWERANSWER i) Brassi) Brassii) Clayii) Clay
iii) Ethylalcohol + wateriii) Ethylalcohol + wateriv) Oiland wateriv) Oiland waterv) Sodawater.v) Sodawater.