Ix Class 2nd Chapte

8/8/2019 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.

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