chemistry full

RAYNOTES 2009

09

OLevelSc(Chemistry)v1.5EasynotessummarizedforOLevels

Hong Ray Corporations

Science(Chemistry)Summarizedversion1.5RAYNotes2009(Hardcopy)

Chapter1Summary

1) Matterismadeupofparticles.

Solid(Fixedshape,HighDensity)Particlesclosetogether,OrderlyArranged,Heldbystrongforcesinfixedpositions

Liquid(Nofixedshape,HighDensity)Particlesclosetogether,NOTinorder,Strongforces,(betweenparticles)Vibrate&Freetomove

Gas(Nofixedshape,Lowdensity)ParticlesFarapartWeakforces(Betweenparticles)FreetomovearoundPressureisduetotheparticlesbouncingoffwallsofcontainer.

ApparatusTomeasure:

Mass ofchemical,useElectronicBalanceTemperature,useThermometerVol.ofgas,useMeasuringCylinderORBuretteORPipette.

ChangesofState

1) Melting(SolidLiquid)ParticlesgainenergyVibratemoreOccursatmeltingpointEndothermic*Reaction(Becauseparticlesgainenergytobreakbonds)

2) Freezing(LiquidSolid)Occursatfreezingpoint(Alsothem.p.ofpuresubstance)Exthothermic*Reaction(Becauseparticlesgiveoutenergytoformbonds)

*ENdothermicreactionmeansheatorenergyENTER(absorbed/gained)tobreakbond!

*EXothermicmeansheat,energyEXIT(giveout/lose)toformbonds!

NotethatforbothFreezing&Melting,temp.remainsconstantduringtheprocess!

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Chapter2Summary

SEPERATIONOFMIXTURES2.1MixTURES&Compounds

1) Compound2ormoreelementschemicallyjoinedtogetherEg.SodiumChlorideContainsCovalentorIonicBonds

2) Mixtures2ormoresubstanceswhicharenotchemicallyjoinedtogetherEg.IroninSulphurpowder.Canconsistof:

Elements(Iron&Sulphurpowder) Compounds(Saltinwatersalt&waterarebothcompounds) Elements+Compounds(Air)

#PureSubstances

1) Fixedcomposition2) FixedMp/Bp3) Producesonly1spotonchromatogram4) Allmoleculessame(equal)

#Mixture

1) VariableComposition2) VariableBp/Mp3) 2ormorespotsonChromatogram4) 2ormorediff.molecules

Personal Tips: Man Becomes what he thinks about Mooris Goodman - Visualize yourself being able to understand this set of notes perfectly. By truly believing, it must be Fact.

PerformanceimprovementTips:Listentoinstrumentalmusics;(BoroqueisNOTrecommended)asitcanmakeyoutiredTryidealmusicssuchasFreeasabirdandAdaywithyoubyOmar.Alsomakesureyoulistenusingearpiece,NOTspeakers!

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2.2Purification(NotethatmixturesareImpuresubstances)

*Solublemeanscandissolveinwater(eg.Salt)*Insolublemeanscannotdissolveinwater(eg.Sand)

SAND&WATER

CopperSulphatecrystalsfromCopperSulphatesolution

Waterfromseawater

Petroleumtopetrol/diesel

Separatingdyesininks

1) Insolublesolid&LiquidFiltration

2) Solid&LiquidsolutionCrystallization(Obtainingsolid)Solute

3) Solid&LiquidsolutionDistillation(ObtainingLiquid)Solvent

4) 2Liquidsmixed(Miscible)FractionalDistillation

5) MixtureofOrganicCompoundsChromatography(Eg.ColourDyes)

NotethatMisciblemeansmixable(Abletobemixed)

_____________________________________________________________________________________

#FiltrationSeparatingsolidfromliquidPossiblebecoz:

Liquidparticlessmallenoughtogothrufilterpaperpores Solidparticlestoolarge.

SolidobtainedResidue LiquidobtainedFiltrate#CrystalisationObtainingsolidfromSolid&LiquidsolutionORFormationofcrystalsfromacoolingliquid/Saturatedsolution

Process:

1. Dissolvesolidinsolventtogivesolution.2. Solutionheatedtoevaporatesolvent.3. >>Producesahotsaturatedsolution.4. Crystalsofpuresolidformedoncooling.

Generalnotes:ASATURATEDsolutionmeansnomoresolidcandissolveinitAnyquestionthatwantsthemethodtoobtain(make)~crystals,theprocesswillbeCrystalisation!Eg.WhatmethodisusedtomakeCopperSulphateCrystals?Ans:Crystalisation.

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#DistillationObtainingpureliquidfromsolution(Eg.Toobtainpurewaterfromseawater)

Process:

1. Heatsolutioninflask.2. Thesolutionboils3. Pureliquidturnstovapour,leavetheflask.4. Vapourcooledbycondenser,changesbacktoliquid5. >>LiquidobtainediscalledDistillate(Collectedinconicalflask)

Possiblebecause:

PureliquidchangetogaseasilyLowBP Soliddoesnotboil(soremainsinflask)HighBP

GeneralNote:Theconstanttemperatureofprocess=BoilingPointofpureliquid

#FractionalDistillationSeperating2liquidswhicharemixed(Miscible)

Process:

1. Mixtureheated2. LiquidwithlowestBPcomesout1st,(attopoffractionatingcolomn)3. Cooledbycondenser,Changesbacktoliquid4. >>LiquidobtainediscalledDistillate(Collectedinconicalflask)

#ChromatographyForSeperating/IdentifyingmixturesofOrganiccompounds.ForSeperatingmixturesofmetalions.

Personal Tips: Chemistry is actually very easy! I used to get D7 for my Chemistry, but with perseverance for 3 months, I scored A1 in my O-Levels 2008! - If you cant do a question, use a red-pen to circle it, fold the page! Arrive school earlier, clear doubts with teachers outside the staffroom. - You CAN ask ANY of the Science Teachers in your school! - Be Brave to take the 1st step, and everything will be smooth after that. Take the first step in faith. You dont have to see the whole staircase, Just take the first step Martin Luther King

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Chapter3Summary

STRUCTUREOFATOMS3.1Particlesinatoms

Atomsaremadeupof3particles:

1) ProtonsMass:1Charge:+1Location:Nucleus

2) NeutronMass:1Charge:0Location:Nucleus

3) ElectronMass:1Charge:1Location:ontheshells(aroundnucleus)

GeneralNotes:Ifanatomiselectricallyneutral,No.ofproton=No.ofneutronsNo.ofprotons=No.ofelectronNucleonnumbersumofproton&neutron.(Alsocalledmassno.)

3.2Isotopes

IsotopesAtomsofsameelement,butwithdiffno.ofneutron.(Sameprotonno.,diffneutronno.)

Note:

AllelementsformIsotopes IsotopeshaveSAMEchemicalproperties(becozhavesameno.ofoutershellelectrons)

*NotethatthechemicalpropertiesaredeterminedbythenumberofOutershellelectrons.If2~havesameno.ofoutershellelectrons,theywillhavesamechemicalproperties.

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3.3Electronsarrangementinatoms

Anatomwithstableelectronicstructurewillhave2OR8valenceelectrons*Eg:

2.8.88electroninoutermostshell(or2valenceelectron) 2.88electroninoutermostshell 22electroninoutermostshell

Valenceelectronselectronsontheoutermostshell._____________________________________________________________________________________

3.4Ions

IonsParticleswithapositiveornegativeelectriccharge.

Ifanatomdoesnothas2or8valenceelectrons,itisNOTSTABLE!

Notstablemeansitwillreactbygainingorlosingelectrons,justtomakesuretheygeteitheran2or8intheirno.ofvalenceelectrons.

So,whentheygainorloseelectrons,theywillformIons

Eg.Anatomwithelectronicstructure2.8.8.7willneedtogain1electrontoform2.8.8.8(STABLE)2.8.3willhavetolose3electronstoform2.8(STABLE)

Whenanatom:

Gainelectron,itformsNEGATIVEions Loseelectron,itformsPOSITIVEions

Generalnotes:

NegativeIon

Formedwhenanatomgainelectron FormedbynonmetalsPositiveIon

Formedwhenatomloseelectron Formedbymetals Atomsformionstoobtainelectronicstructureofnoblegas(NoblegasareSTABLE)

*ImportantFact:Metalsloseelectrons,nonmetalsgainelectrons

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Chapter4Summary

CHEMICALBONDS4.1CovalentBonding

CovalentBondsFormedbetweenatomsofnonmetals&nonmetals

ADoublebondmeanseachatomprovides2electronTotal=4electronsbeingshared

4.2IonicBonding

IonicBondingFormedbytransferofelectronsbetweenmetals&nonmetals,formingpositive&negativeions.

IonicBondistheforceofattractionbetween+ve&veions.

Eg.2atomsareionicallybonded;Sodium&Chloride.Sodium:2.8.1(Needstolose1)afterlosing1toChloride,itbecomesPOSITIVEionwith2.8Chloride:2.8.7(Needstogain1)aftergaining1fromSodium,becomeNEGATIVEionwith2.8.8

>>Then,theyllbecalledSodiumChloride(Acompound)Becozitschemicallyjoinedtogether..

GeneralExamples:

SodiumChlorideIonicBond;becozSodiumisametal,Chlorineisnonmetal.MagnesiumSulphateIonicBond;becozMagnesiumisametal,Sulphurisanonmetal

*RemembertonametheMETAL1stthentheNONMETAL!Eg.WedonotnameChlorideSodium,WeonlynameSodiumChloride!SowhyisntitcalledSodiumChlorine?AllelementsinGroupVIIchangestheirtailnamewithidei.e.FluorinebecomesFluoridewhenitformsacompound(eg.LithiumFluoride)IodinebecomesIodidewhenitformsPotassiumIodideCompound

CarbonDioxide(CO2)CovalentBond;becozCarbonisanonmetal,OxygenisalsononmetalMethane(CH4)CovalentBond;becozMethaneconsistofCarbon&HydrogenBothisnonmetal

*MustrememberthatHydrogenisconsideredaNONMETAL!

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4.3FormularofIonicCompounds

Theformularcanbeexplainedinastorymode..

FindingformularofBariumChloride,ItisNOTassimpleasBaCl!!

*RememberthatIonicCompoundsTransferofelectrons!*Metalsloseelectrons,nonmetalsgainelectrons*Gainelectron+veions/Loseelectronsveions

Readstorymode:(Forweakerstudents)

Bariumisfromgroup2,henceithas2valence(outershell)electrons ItisametalSoithastoLOSE2electronstobecomestable! Sowhenitloses2electrons,itformspositiveionswiththecharge+2 SoBariumisBa2+

Chlorineisfromgroup7,ithas7valenceelectrons ItisanonmetalsoIthastoGAIN1electrontobecomestable! Whenitgains1electron,itformsnegativeionswiththecharge1

Thuswhenyouput2together,itwillbeBa2+Cl1 Becausetheruleisthatthe+vechargemustbalancethevecharge, Sotomakeisbalance,justwriteisasBaCl2//Answer

Personal Tips: Feel grateful for receiving this set of notes, and you will experience more great things coming..

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TheShortcutmethodbelowwillworkeverytime!Itsthebestmethodtodeterminetheformularofioniccompound!

Question:FindtheformularofMagnesiumSulphate(MgS)

1. Writesymbolsofelementssidebyside(Metaldennonmetal)

MgS

2. Writetheionformedwhentheybecomestable

Mg2+S1

MgbecomesMg2+becauseitisfromgroup2,has2valencesoitlose2toformMg2+ion.SbecomesS1becauseitisfromGroup7,has1valence,sohastogain1toformS1ion

3. Crossthecharges(Ignoringthe+andsigns)Mg2+S1

Mg1S2MgS2(Ans)Practice makes perfect! Do not give up on your chemistry Clear doubts as often as possible If you are not interested in this subject, continue to clear doubt, and when you get good results, youll love chemistry! - Hong Ray (Former Student)

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4.4 PropertiesofCovalent&IonicCompoundsNotethatisthistopichasalwaysbeentestedeveryyear,andwillcontinuetobetestedinGCEOLevelexams!!

Justmemorisetheproperties:

#Covalent

1. Doesnotconductelectricityinanystate(Becozdoesnotcontainions)2. Lowmeltingpointlessthan200oC(Becozweakforcesofattractionbetweenmolecules)3. Insolubleinwater,Solubleinorganicsolvents!

#IonicCompound

1. Conductelectricityismolten,AqueousstateBecauseitcontainmovingionsDoesnotconductonsolidasionscannotmove

2. HighMeltingpointMorethan1000oChenceioniccompoundsaregenerallysolidsatroomtemp.Becauseofstrongforcesofattractionbetweenions

3. Solubleinwater

Ifaquestion(>5m)asksyoutoexplainwhyIoniccompoundshavehighBP,CovalenthasLowBP,answerinthisformat:

1) Ioniccompoundsconsistentirelyofions.2) Theoppositechargedionsareheldclosetooneanotherbyverystrongelectrostatic

attraction,knownasionicbonds.3) Hencelargeamountofenergyneededtobreakionicbonds.thereforehighB.P

4) Covalentcompoundsconsistentirelyofmoleculesastheyareformedbysharingof

electrons.5) Forcesbetweenmoleculesareveryweak.6) Onlysmallamountofenergyneededtobreakbinds.thereforelowB.P

Generalnotes:

Electricityconductivitylinkedtopresenceofmovingions Boilingpointlinkedtoforcesofattractionbetweenmolecules/ions.

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Chapter5Summary

METALS5.1PhysicalPropertiesofMetals

#Metals

1. Goodconductorsofheat/electricityContainelectronsthatarefreetomovethroughthemetal.Formakingcookingutensils/wires

2. HighMp,BpHavestrongbondsbetweenatoms,alotofenergyisneededtoweaken&breakbonds.

3. Malleable(Canbepressedintodiff.shapes)Layersofmetalscanslideovereachothereasily

#AlloysMixtureofmetal+otherelement

Brass=Zinc+Copper Steel=Iron+Carbon

Note:Alloysareusedbecausetheyarestronger&harderthanpuremetals.Atomshavedifferentsizes,whichpreventsthemfromslidingovereachother

Personal Tips: Always remember that if you experience doubts, NEVER HESITATE TO ASK! Asking the teachers is far better than discussing with your classmates!

- If one teacher cant make you understand, try another teacher. Youll surely get one that suits you!

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#5.2ReactivitySeries

1) PotassiumExplosionwithcoldwaterExplosionwithDilutehydrochloricacid

MoreReactive

Potassium

Sodium

Calcium

Magnesium

Aluminium

Zinc

Iron

Lead

Hydrogen

Copper

Silver

Gold

LeastReactive

2) SodiumVeryfastreactionwithcoldwaterExplosionwithHCl

3) CalciumFastreactionwithwaterFastreactionwithHCl

4) MagnesiumVeryslowreactionincoldwaterFastreactionwithHCl

5) ZincNoreactionwithcoldwater,BurnsinsteamFastreactioninHCL(heated)

6) LeadNoreactioninwaterVeryslowreactioninHCl

7) CopperNRinwaterNRinHCl

8) SilverNRinwaterNRinHCl

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#5.3ExtractionofMetalsfromOres

Orearockwhichusefulmetalscanbeobtained.

Metalisobtainedfromitsorebychemicalreaction:ExtractionExtractionisdoneinsideafurnace.

*MethodsofextractionThemethoduseddependsonhowreactiveisthemetals!

VeryReactiveMetals

Electrolysis For:(Decomposingmetalcompoundwithelectricity) Potassium

SodiumCalciumMagnesiumAluminium

_________________________________________________

ModeratelyReactiveMetals

Heatingmetaloxidewithcoke For:

ZincIronLead

_________________________________________________

LowReactivityMetals

Heatingmetalcompoundsinair For:CopperSilver

Note:Electrolysisisexpensive,hencealuminumisexpensive.

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#ExtractionofIronIronExtractedfromoreHaematite(Impureiron(III)oxide)intheblastfurnace

Blastfurnacecontains:

1. Ironore2. Coke3. Limestone

Blastsofhotair(containingoxygen)areblownintothefurnacenearthebottom.

MoltenIron

MoltenSlag

HotairHotair

Ironore,coke,limestone

WasteGasesWasteGases

ChemicalReactionsinBlastFurnace

1. Cokeburnsinairtoproducecarbondioxideandlotsofheat.C+O2CO2

2. CarbonDioxidereactswithmorecoketoproduceCarbonMonoxide.C+CO22CO

3. CarbonMonoxidereactwithiron(III)Oxidetoproducemolteniron&carbondioxide.3CO+Fe2O33CO2+2Fe

4. Impuritiesinmoltenironareremovedbylimestone.CaCO3CaO+CO2

5. CalciumOxideformedcombineswithSilicapresentintheoretoformslag,whichistappedout.CaO+SiO2CaSiO3

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#5.4Recycling

RecyclingmetalsCollecting,meltingdownstrapmetalstomakeblocksoffreshmetals(Formakingnewmetalobjects)

AdvantagesofRecycling:

1. Metaloresinthegroundcanlastlonger.

2. Moneysavedinenergyneededtoextractnewmetalsfromore.

3. Scrapmetalisremovedfromtheenvironment,preventsland&waterpollutionduetocorrosion.

DisadvantagesofRecycling:

1. Expensivetocollectstrapmetalsfrommanysources

2. Metalfumesproducedinmeltingofscrapmetalscancausepollution.

_____________________________________________________________________________________

#5.5Aluminium

1) Quiteareactivemetal(Higherinreactivityseries) CorrosionResistant

ThinlayerofAluminiumOxidepreventscorrosion.(Preventsair,waterfromreachingthemetalunderneath)

Uses: Food/drinkcontainerCorrosionResistant. AircraftbodiesLowdensitysothataircraftbodyislight. OverheadpowercablesGoodelectricalconductor,lessdense

comparedtocopper(Cablecanbelighter)

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#5.6Iron&Steel

RustingDuetoairandwaterreactingwithiron.Afterreaction,ironbecomesIron(III)Oxide,FeO3

#RustingPrevention

I. BarrierMethodUseofpaint,grease,oiloranothermetal.eg.tin

II. SacrificialProtectionCoatingironorsteelwithamorereactivemetal.

Eg.

GalvanisingCoatingiron/steelwithzinc.(Ironcorrodesinsteadofzinc)

Magnesiumattachedtoironpipelinestoprotectfromrusting.

IronPipeline

Magnesium

InsulatedCoppercable

Personal Tips: To remember Chemistry Facts, write out in a piece of plain paper (NOT FOOLSCAP).. Just repeat writing them out..

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18

Chapter6Summary

THEPERIODICTABLE6.1TheStructureofthePeriodicTable

1) Elementsarrangedinorderofprotonnumbers.

2) VerticlesColomnsGroupsAllelementsinGroup2have2valenceelectronsAllelementsinGroup3have3valenceelectrons..etc

3) HorizontalrowPeriodLeftRight=MetalsNonmetalsAllelementsinPeriod1have1outershellofelectrons(Eg.Hydrogen:1.Helium:2.)AllelementsinPeriod2have2outershellsofelectronseg(Eg.Lithium:2.1Oxygen:2.6)

AllelementsinPeriod3have3outershellof...~(Eg.Magnesium:2.8.2Chlorine:2.8.7)

*NotethatHydrogenisconsideredanonmetal(ForansweringOLevelexaminations)

Elementsinsamegroup:

Samechemicalproperties Sameno.ofvalenceelectrons Diffphysicalproperties Differentempiricalformula

Notethatthechemicalpropertiesofanelementislinkedtotheno.ofvalenceelectrons.Sobecozelementsinsamegrouphavesameno.ofvalenceelectrons,theywillhavesamechemicalproperties.


#6.2Group1Elements

Group1elementsarecalledAlkalimetals

Becauseitsfromgroup1,ithas1valenceelectron

Andbecauseitsametal,itcanlose1electronandformapositivechargedion:+1(whichismorestable)

Eg.Potassium:2.8.8.1Lithium:2.1Sodium:2.8.1

Group1elementsareveryreactive!!!(BottomMOREREACTIVEthanTOP)

TheyreactwithcoldwatertoformAlkalinesolutionofMetalhydroxide&Hydrogengas.

Soft,Silverymetalswithlowdensityandmeltingpoint(BottomLOWERm.pthanTOP)!!

Examplereactions:

1) Lithium+WaterLithiumHydroxide+HydrogenGas

2Li+2H2O2LiOH+H2

2) Sodium+WaterSodiumHydroxide+HydrogenGas

2Na+2H2O2NaOH+H2

3) Potassium+WaterPotassiumHydroxide+HydrogenGas

2K+H2OKOH+H

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#6.3Group7Elements

Group7elementsarecalledHalogens Becauseitsfromgroup7,ithas7valenceelectrons

Andbecauseitsanonmetal,itcangain1electronandformanegativechargedion:1(whichismorestable)

Eg.Fluorine:2.7Chlorine:2.8.7

Group1elementsareveryreactive!!!(BottomLESSREACTIVEthanTOP)

Theyformacidicsolutions

Colouredsubstanceswithlowmeltingpoint(BottomHigherm.pthanTOP)!! Theyarediatomicmolecules(Eachmoleculecontains2atoms)

Eg.Cl2,Br2,I2,etc

Coloursofelementsbecomedarkerdownthegroup,LiquidSoliddownthegroupFluorine:PaleYellow(Gas)Chlorine:YellowishGreen(Gas)Bromine:ReddishBrown(Liquid)Iodine:Black(Solid)Astatine:Black(Solid)

Morereactiveelementsdisplacelessreactiveelements(Displacemeansreplaceotherlessreactiveelements)

Eg.WhenChlorinereactswithPotassiumIodide,:(DisplacementReaction)

ChlorineismorereactivethanIodide WhichmeansChlorinehavethepowertokickoffIodide,andreplaceitsposition! Soafterthereaction,itllbeleftwithPotassiumChlorineANDIodide.

ChemicalEquation:

Cl2+2KII2+2KCl

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#6.4TransitionMetals(ForstudentstakingPureChem)

TransitionElementsareallmetals,theydonotbelongtoanygroup Theyhavehighdensityandmeltingpoint(1500oC) Actsasgoodcatalysts Formcolouredcompounds Theyhavevariablevalencies(donothavefixedno.ofvalenceelectrons)

*AlsonotethatGroup2elementsarecalledAlkalineMetals

*RAYResource2009:Refertotheattachedmodifiedperiodictabletogetamoredetailedviewoftheentirechapter.Thiswillhelpyourememberthefactsbetter!Alternatively,thisresourceisavailableforfreedownloadatrayrevision.webs.comBelow:PreviewofPeriodicTable

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22

Chapter7Summary

THEENVIRONMENT7.1CompositionofAir

Airisamixtureofgases. 79%Nitrogen 20%Oxygen 1%Othergases(mainlyargon) AlsocontainsmallamountofCarbonDioxide&watervapour.

7.2UsesofOxygen

1) Oxygenisusedforcombustion.CombustionmeansburningEg.CombustionofCarboninblastfurnacetoproduceCO2

Otherinfo:2) Oxygententshelpspeopletobreathe3) Makingsteelbyburningimpuritiestooxidesthenremoved.4) OxyacetyleneAcetylenegasburninO2,hightemp.meltsteel

5) LimestonerockaformofCalciumCarbonate


7.3AirPollution

Aircontainslargenumberofharmfulsubstances(Pollutants):1) CarbonMonoxide

DuetoincompletecombustionofCarbonFuelsCausebreathingdifficulties/headaches!!Solution:SupplyexcessairtoensurecompletecombustionEg.Fitvehicleswithcatalyticconverters.

MoreFACTS:

Incompletecombustionmeanslackofoxygentoburn. CarbonMonoxideisabsorbedbyhaemoglobininourblood, Preventsourbloodfromabsorbingoxygen Breathingdifficulties,etc.

2) MethaneDuetoBacteriaDecayofvegetation(Farmanimalsdung)CauseGlobalwarmingNoeasysolutions

3) OxidesofNitrogenLightning&VehicleenginesBreathingdifficulty/Acidrain/Produceozone!!FitvehicleswithCatalyticconverters

4) OzoneSunlightactingonunburnedhydrocarbons&NitrogendioxideIrritateseyes&lungs!!Reducevehicleemissionsofpollutants.

5) SulphurdioxideCombustionoffossilfuelslikecoalBreathingdifficulty/AcidrainBurnlesssulphurcontainingfuels

6) UnburnedhydrocarbonsVehicleenginesProducesOzoneFitvehicleswithcatalyticconverters.

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AcidRain

SulphurDioxideandNitrogenDioxidearemaincausesofacidrain. Killsfishinfreshwaterlakes PreventedbyFittingmotorvehicleswithcatalyticconverterstoreduceemissionsof

nitrogenoxides.

GeneralNote:Metalsformbasicoxides,Nonmetalsformacidicoxides.ThusBothSulphur&NitrogenformAcidicoxidesbecoztheyarebothnonmetals.

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25

Chapter8Summary

ACID&BASES8.1PropertiesofAcids

CommonAcids:

1. HydrochloricAcidHCl2. NitricAcidHNO33. SulphuricAcidH2SO44. EthanoicAcidCH3COOH

Whenanaciddissolveinwater,itproducesHydrogenIons,H+. Acidturnsbluelitmuspaperred Acidturnsuniversalindicatorred pHvaluelessthan7Rules:(MUSTREMEMBER!)

1) ACID+METALSALT+HYDROGENGAS(Pleasenotethataciddonotreactwithanymetalsbelowhydrogeninthereactivityseries!!!)

SOwhatImeanbysalt?YoujustneedtoknowthatNitrate,Sulfate,Chloride,CarbonateARESalts!Thenameofsaltproducedsimplydependsonwhatacidisused.SoifyouuseHydrochloricacidtoreactwithametal,itwillformmetalChloride&HydrogenGas.Eg.IfyouputHydrochloricAcidandSodium,ItformsSodiumChloride&HydrogenGasEg.IfyouputSulphuricAcidandZinc,ItformsZincSulfate&HydrogenGas

2) ACID+BASESALT+WATER*Mustremember:AbaseisMetalOxideorHydroxide(OxidecontainsO,HydroxidecontainsOH)

WhichmeansanymetalthatcontainsanoxideorhydroxideinitsnameisaBASE!!

Eg.H2SO4+CuOCuSO4+H2OACIDBASESALTWATER

Eg.HCl+NaOHNaCl+H2OACIDBASESALTWATER


3) ACID+CARBONATESALT+WATER+CARBONDIOXIDEGASNote:AnythingthatcontainsaCO3initsnameisacarbonate.i.e.MgCO3,CuCO3,etcarecarbonates

Eg.2HCl+CuCO3CuCl2+H2O+CO2ACIDCARBONATESALTWATERCARBONDIOXIDE

Eg.H2SO4+MgCO3MgSO4+H2O+CO2ACIDCARBONATESALTWATERCARBONDIOXIDE

*Extranotes:Beforeyoubalancetheequation,alwayscheckifyouhavewrittenthecorrectformulas.Eg.CuCl2notCuCl.Ifyouareunabletobalance,itmustbeduetoincorrectformulas.Approachteachersforhelponbalancingequationsasthistypeoftopicisbettertaughtverbally.Again, BE BRAVE! Take the 1st step in faith..

8.2PropertiesofBasesRemember?BasesareMetalOxidesorHydroxides,soanythingthatcontainsthis2wordsareBases!

Thereare2typesofBases;SolubleBase&InsolubleBase

AlkaliareSolubleBases

Youonlyneedtoremember4alkalis:1. PotassiumHydroxide2. SodiumHydroxideNaOH3. CalciumHydroxideCa(OH)24. AmmoniaNH3

Justrememberthe4solubleBasesbyPO,CA,SO,NH4

WhenanAlkali(SolubleBase)dissolvesinwater,itproducesHydroxideIons,OH. AlkaliturnsRedlitmuspaperBlue Alkaliturnsuniversalindicatorblue pHvaluemorethan7

*ExtraInfo:Farmersputalkali,CalciumHydroxide,ontothefieldstoneutralizeexcessacids.

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8.3ThepHScale

ThesmallerthepH,themoreacidicisthesolution.(MeanshigherconcentrationofHydrogenIons,H+)

TheLargerthepH,themorealkalineisthesolution.(Meanshigherconcentrationofhydroxideions,OH)

Eg.SomethingwithpHvalueof3ismoreacidicthansomethingwithpHvalue9.

pHvalues:

16=Acidic 7=Neutral 814=Alkaline

ThepHofasolutioncanbemeasureusing:

1. UniversalIndicator2. pHmeter

8.4Oxides

OxidesAreCompoundsofoxygenwithotherelements

3TypesofOxides:

1. Acidic2. Basic3. Amphoteric

Remember?Metalsformbasicoxides,Nonmetalsformacidicoxides.

HenceAcidicOxidesOxidesofNonmetalsBasicOxidesOxidesofmetals

Eg.SO3,CO2,SO2,NO2areAcidicOxidesbecozS,C,Narenonmetals.

Eg.MgO,CuO,CaOareallBasicOxidesbecozMg,Cu,Caaremetals.

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AcidicOxide+WaterAcidEg.SO3+H2OH2SO4

Acid+BaseSalt+WaterRememberthatabasereferstometaloxidesorhydroxides.

ThusBasicOxide(Base)+AcidSalt+Water

Eg.CaO+2HNO3Ca(NO3)2+H2O

AmphotericoxidesMetalOxidesthatreactwithbothacid&alkalistoformsalts

ForOLevels,youonlyneedtomemorisethe3AmphotericOxides:

1. AluminiumOxideA2O32. ZincOxideZnO3. LeadOxidePbO

Personal Tips: You must memorize the Acid+MetalSalt+Hydrogen Gas etc.. A full list of equations summarized from all chapters is attached with this .zip package. To remember better, photocopy that list, paste it on the wall of your room or restroom - It works!

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8.5SaltPreparation

Personal Tips: This might seem the hardest chapter to you now. But in truth, it interesting and simple to do! - You MUST Clear Doubts with your teachers regularly, and youll see miracles in your next test results.

First,Youmustmemorisethesecretmethodtoseeifasaltissoluble.(Solubilitytablesfromyourtextbooksarehardertomemorise)

Soluble Insoluble Nitrate All -

Sulfate Rest Ba, Ca, Pb

Chloride Rest Ag, Pb

Carbonate Group1 Rest

Remembervia:BakedChickenPastaAtPastamania

SecretTablecontributedbyMsAida(BtVSS,MOESingapore)

ThistablehelpsyouknowwhetherasaltissolubleornotHowtouse?

Factsoftable:

AllNitratesaresoluble AllCarbonatesthatarefromgroup1intheperiodictablearesoluble;therestare

insoluble.Eg.PotassiumCarbonateissoluble,BariumCarbonateisinsoluble

AllsulfatesaresolubleexceptBariumSulfate,Cacium~,Lead~.Eg.ZincsulfateissolublewhileCalciumsulfateisinsoluble

AllChloridesaresolubleexceptSilverChloride,LeadChloride..Eg.CalciumChlorideissoluble,LeadChlorideisinsoluble

SoisMagnesiumSulfatesoluble?YES

IsSodiumCarbonatesoluble?YES

Youstillneedtoknow1fact:Allgroup1saltsareSOLUBLE!WhichmeansLithiumCarbonate,PotassiumChloride,etcareconfirmedsolublesincetheyrefromgroup1ofperiodictable.Youcanprepare(make)saltsinmanyways,dependingonwhattypeofsaltitis.

29


*ImportantNotes:

TitrationMethod(SolubleBase+Acid)

ToprepareanysaltthatisfromGroup1.(Eg.PreparingSodiumSulfate)1) Add25cmofacidtoaconicalflask2) Addafewdropsofindicator.(eg.PhenolPhthalein)3) AddSodiumHydroxideusingaburetteuntilindicatorchangescolour.4) Repeatexperimentwith25cm3ofSulphuricAcidbutNOindicator!5) AddsamevolumeofSodiumHydroxide.6) SodiumSulfateisobtainedbyevaporating&crystalisingthesalt.

______________________________________________________________________________

PrecipitationMethod(Soluble+Soluble)

ToprepareanyInsolublesalt.(Eg.PreparingSilverChloride)1) AddSilverNitratewithSodiumChloride.2) Filterouttheprecipitate.3) Washtheresiduewithdistilledwater.4) Leavetheresiduetodry.

Touseprecipitation,justmakesurethesaltyouwanttomakeisinsoluble.ThemethodrequiresyoutouseSolublesalt+Solublesaltsousingthetable,justfind2saltsthataresolubleandcontainpartofthename.______________________________________________________________________________

Forexample,IwanttomakeaninsolublesaltcalledCalciumSulfate.

1st,IneedtofindCalcium~thatissoluble.AndIalsoknowthatAllnitratesaresolubleSothe1stsaltIuseisCalciumNitrate.

Next,Ineedtofindsomethingsulfatethatissoluble.IalsoknowthatallGroup1saltsaresoluble..SoIcanuseLithiumSulfateasmy2ndsalt.

Byreacting2salts,IllgetwhatIwant,whichisCalciumSulphate!!

Ca(NO3)2+Li2SO4CaSO4+2LiNO3

Whentheyreact,theysimplyjustchangepartners..

30


ToprepareSolublesalt,butNOTfromGroup1:

Thereare2ways:1) Solublesalt+solublesalt2) SolubleSalt+InsolubleSalt

Eg.ToprepareMagnesiumSulfate:

IuseMagnesiumNitrate&SodiumSulfate(Botharesoluble)

Mg(NO3)2+Na2SO4MgSO4+2NaNO3

Alternatively,IcanalsouseSoluble+Insolubleway.IuseMagnesiumNitrate&BariumSulfate(1issoluble,otherisnot)

Mg(NO3)2+BaSO4MgSO4+Ba(NO3)2

Soluble Insoluble

Nitrate All -

Sulfate Rest Ba, Ca, Pb

Chloride Rest Ag, Pb

Carbonate Group1 Rest

Rememberingthetable

3rdrow:BakedChickenPastaAtPastamania

1strow:NoSuperChildishChildren

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32

Chapter9Summary

ChemicalAnalysisChemicalAnalysisisaboutfindingthenameofanunknownsaltbycarryingoutseveralexperiments/tests..Allsaltscontains2parts:Cation(+vechargesions)&Anion(vechargedions)

Thequestionusuallyshowstheobservationsoftests,andyouwillhavetofindoutwhatisthesaltaccordingtotheobservation.

TestingforCATIONS:Withthistable,youdontneedtomemorisethecoloursofdifferentsalts!JustdrawoutthistableduringyourOLevels

CATION NaOH NH3

Colour Soluble or Insoluble

Colour Soluble or Insoluble

Cu2+ B I B S

Fe2+ G I G I

Fe3+ R I R I

Ca2+ W I - -

NH4+ N - - -

Zn2+ W S W S

Al3+ W S W I

Pb2+ W S W I

TheCATIONStableshowsthecolourchangesobservedwhenthesaltisaddedtoSodiumHydroxide,NaOH,orAqueousAmmonia,NH3.

Italsoshowswhetherthesaltissolubleinexcessalkali(NaOH,NH3)

Forexample,Icarryoutanexperimenttofindoutwhatanunknownsaltcontain. WhenIaddNaOHtothesalt,colourchangestowhite,andwhenIaddexcessofNaOH,

itdissolved(Soluble). Next,ItriedaddingNH3tothesalt.Thecolouralsochangestowhite,anditisalso

solubleinexcessNH3. Then,Imatchthetestresultswiththetable.TheunknownsaltcontainsZinc,Zn2+

ColourofObservationSolubleorInsolubleinexcessAlkali


TestingforANIONS:

ANION Testedwith

Observations

Chlorine AgNO3 AgCl White

Carbonate Acid CO2 CarbonDioxide(TurnLimewaterchalky)

Sulphate Ba(NO3) BaSO4 White

Nitrate Al,NaOH NH3 Ammonia(Turnredlitmusblue)

Iodide Pb(NO3)2 PbI2 Yellow

Eg.ItestedsaltxwithSilverNitrateAgNO3,awhiteprecipitateisformed.ThismeansthatsaltxcontainsChlorine..(ThewhiteprecipitateisAgCl)

TestforGASES:

AmmoniaUsedamplitmusPaperTurnsfromredtoblue

CarbonDioxideUseLimewaterWhitepptformed(TurnsChalky)

ChlorineUseDampbluelitmuspaperBleachesLitmuspaper(LitmusTurnscolourless)

HydrogenUseBurningSplint'Pop'SoundHeard

OxygenUseGlowingSplintGlowsBrighterorBurstintoflames

SulphurDioxidePlaceadropofPotassiumDichromate(VI)onFilterpaperOrangeDichromateturnsgreen.

ImportantTips:YouMUSTmemorisethe3powerfultablesabove!Theyregoingtohelpyoumemorisethingssoeasily.Youwontbeabletofindanyeasystuffslikethatinyourtextbook!Soitsyourchoicetouseitorleaveit.Whateveryouchooseisright.

33


34

Chapter10Summary

MOLECONCEPT10.1CountingAtoms:TheMole

*This chapter is better to be taught verbally by your teachers as its not easy to explain in words. Thus, approach teachers when in any doubt!

Memorise this 4 IMPORTANT Formulas:

Somefacts:

1. 1Mole=6x1023particles2. MolarMassMassof1moleofanysubstance3. RelativeAtomicmass=Molarmass,thediff.isthatMolarmasshasagramsonit.

32

4. Eg.Sulfur:S16hasamolarmassof32g.Whichalsomeansitcontain32gpermole.

#10.2MolarVolumeofGases

1Moleofanygas,hasthesamevolumeof24dm3atroomconditions(25oC,1Atmosphere) Eg.AmmoniaNH3MolarMass=17g

CarbonDioxideCO2MolarMass=44g 1dm3=1000cm3

Massof

Sample

No.of

MoleMolarMass

No.of

Particles

No.of

Mole 6x1023

Volumeof

Gas

No.of

Mole 24dm3

Mole

ConcentrationVolume

24dm3


#10.3Concentrationofsolutions

+ SOLIDLIQUIDSolute Solvent Solution

DissolveinToForm

Concentrationismeasuredinmol/dm3

#10.4MolecularFormula

The Molecular formula shows the actual number of each type of atoms present in a compound

Tofindthemolecularformulaofacompound,youneed:

1. EmpiricalFormulaofcompound2. Relativemolecularmass

Forexample:

Therelativemolecularmassofacompoundis62Theempiricalformulaofthecompoundis(COH3)

1) Calculate:(COH3)=12+16+3=312) Writethestatement:62=n(31)

3) Findn:n=62/31=24) n=2

5) Add2intotheformula:(COH3)2=C2O2H6(ans.)

#10.5EmpiricalFormula

Empirical Formula the simplest formula of a compound which shows the ratio between the atoms of each element.

Findingtheempiricalformulaisaboutfindingtheno.ofmolesofbothitems,dendevidetheirvalueswiththesmallervalue.

35


36

Eg.Asubstancecontain80%Copper,20%SulfurFindtheempiricalformula.

1) Findtheno.ofmoleofbothitems!no.ofmoleofCopper: 80/64=1.25molno.ofmoleofSulfur:20/32=0.625mol

2) Youcompare2values;0.625isasmallervalueright?

3) So,devidebothvalueswith0.625:1.25/0.625=20.625/0.625=1

4) Den,youputthenumbersinthisform:Cu2S(ans)


37

Chapter12Summary

OXIDATION&REDUCTIONMustmemorise:

Oxidation

1. GainOxygen2. LossHydrogen3. Losselectrons4. Increaseinoxidationstate

Reduction

1. Gainhydrogen2. Gainelectron3. LossOxygen4. Decreaseinoxidationstate

Eg.PbO+MgPb+MgO

Generalnotes:

Asubstancethatcausessomethingtobeoxidisedisanoxidisingagent. Asubstancethatcausessomethingtobereducedisanreducingagent.

Anoxidisingagentitselfisbeingreducedinthereaction Anreducingagentitselfisbeingoxidisedinthereaction*RedoxreactionAreactioninwhichOxidationandreductiontakesplace.

OxidisingAgent(CausesMgtobeoxidised)

Reduced(ItlosesoxygentobecomePb)

OxidisedbecauseitgainsoxygentobecomeMgO

Reducingagent(CausesPbotobereduced)


#Loss/Gainofelectrons

Eg.2Na0+Cl202Na+Cl

SodiumloseselectronitisoxidisedChlorineGainselectronReduced

#OxidationState

*Allelementsonlyhavechargeswhentheyformcompounds.Eg.MgNOCHARGEMg+OGotchargeOxidationstateisthechargeonaniondependsonwhichgroupoftheperiodictabletheelementsarein.

Eg.WhatistheoxidationstateofSulfurinH2SO4?

H2+

(H+ each) Oxidationstateof8(Each2)

Note:Thenumberofpositivechargesmustbalanceno.ofnegativecharges.

HenceOxidationstateofSulfuris82=+6

Personal Tips: You must ASK YOUR TEACHERS if you dont understand any question or topic! Do Not Delay or you might regret soon If you still dont understand after his/her explanations, DO NOT pretend to have understood! Just ask him/her to explain again.

38


#Oxidation&ReductionaschangesinOxidationstate

Remember:

IncreaseinOxidationstateOxidationEg.MgMg2+(Oxidationstategainsfrom0to+2)Mgisoxidised.

DecreaseinOxidationstateReductionEg.ClCl(Oxidationstatedecreasesfrom0to1)Clisreduced.

39


40

Chapter13Summary

RATEOFREACTIONS Slowreactions:

RottingapieceofwoodinthegroundRustingofasteelfence

Fastreactions:DynamiteexplodingBurningapieceofmagnesiuminair

Notes:

1. Reactionstakesplacewhenparticlescollide.2. Mostcollisionsdonotproduceareactionbecausecollidingparticlesneedaminimum

energytoreactwhentheycollide.ThisiscalledActivationEnergy

#Factorsaffectingspeedofreaction(ParticlesTheory)

1) ConcentrationofsolutionThehighertheconcentrationofsolution,thefastertherateofreaction.Becausetheparticlesareclosertogethersotheycollidemorefrequentlyandsothereweremorefrequentreactions.Note:Onlyappliestoreactionsofsolutions.

2) PressureThehigherthepressure,thhigheristherateofreaction.Becausetheparticlesaresqueezedclosertogether,sotheycollidemorefrequentlyandsothereweremorefrequentreactions.Note:Onlyappliestoreactionsofgases.

3) ParticlesizeofsolidThesmallertheparticlesize,thehighertherateofreaction.Becausethetotalsurfaceareaofthesolidincreasessoreactingparticlesofliquidandgasescollidemorefrequentlywiththesurfaceandsotherearemorefrequentreactions.Note:Onlyappliestoreactionsofsolids.


4) TemperatureThehigherthetemperature,thefastertherateofreaction.Becauseathighertemperature,theparticleshavegreaterkineticenergy,sotheyreactmoreoftenwhentheycollide.

#Chapter14Heatchangesinreactions

1) Exothermicve

Energy/HeatReleased Solution/TesttubeBecomeshot BondForming H=ve(NegativeValue) Eg.AllcombustionreactionlikeburningMagnesiuminair/Reactionofacidwithalkalis

Why solution turns hot when heat is given out?Heatisreleasedfromthesolutiontoyourhandssoyoufeelthetesttubeishot.ReactionDiagram:

TemperatureDiagram:

41


2) Endothermic+ve

Energy/HeatAbsorbed Solutionturnscold BondBreaking

Eg.Freezingofice

H=+ve(PositiveValue)

Why solution turns cold when heat is taken in?

Theheatinyourhandsisabsorbedsoyou'llfeeltesttubebecomingcold.

ReactionDiagram:

TemperatureDiagram:

*Mostreactionsareexothermicastheymakethetesttubeturnhot.Info:Energyistakenintobreakbonds.Energyisgivenoutforbondforming.

HreferstoDeltaHHistheamountofheatenergytakenin/givenoutduringachemicalreaction.

42


Chapter15Summary

FUELS

#15.1FossilFuels

1) Petroleum&NaturalGasarethe2mainfossilfuels.Fossilfuelswereproducedfromplantandanimalremains(Longago)

2) PetroleumAstickyblackliquidandamixtureofhydrocarbons.3) NaturalGasconsistmainlyofmethane

#15.2FractionalDistillationofPetroleum

Petroleumisseparatedtodifferentfractionsbyfractionaldistillation. Seperationcantakeplacebecausepetroleumisamixtureofsubstanceswith

differentboilingpoints.

ImportantProcess:

1. Thepetroleumisheatedinafurnacetovapouriseit.2. Thevapourcondensestoliquidatdifferentheightsupthefractionatingcolomn,where

itcomesoutasdifferentfractions.3. Afractionismixtureofhydrocarbonwitharangeofboilingpoints.

Thehydrocarbonsarealkanes.

43


44

#15.2(b)FractionatingColomn

3575oC

70170oC

170250oC

250340oC

350500OC

PetroleumGases(Propane,Butane,etc)TomakeCylinderGasforcooking

Petrol(Gasoline)Fuelsforcars

Naptha(MakingChemicals)

Kerosene(Paraffin)Fuelforjetaircraft

Diesel Fuelfordieselenginesinbuses

LubricatingOilsmakingLubricants,Polishes,wax

BitumenSurfacingRoads

Petroleum

LowerBoilingpoint(Below25oC)Smallermolecules

HigherBoilingpoint(Above500oC)Largermolecules


45

Youmustremembertheorderoffractionsandtheiruses!

2) Petrol

e(Paraffin)

n

1) Petroleum

3) Naptha4) Kerosen5) Diesel6) LubricatingOil7) Bitume

#CombustionofFossilFuels

airproducewaterandcarbondioxide(Completecombustion)

*Carbonmonoxideandsootwillalsobeproducedifnotenoughair(Incompletecombustion)

1) Hydrocarbonburnsin

CH4+CO2CO2+2H2O

2)

#15.2(c)

Petrolanddieselareneededasfuelsforvehicles Petroleumdoesnothaveenoughofthem. HenceCrackingisdone

Alkane(Hydrocarbon)

Air(Oxygen)Mainlycarbon

Areactioninwhichbighydrocarbonmoleculesarebrokendownintosmallermoleculesbyheat.


46

Chapter16Summary

HYDROCARBONS16.1Alkanes

1) Alkanesaresaturatedhydrocarbons(Nomoreatomscanbeaddedtotheirstructure)2) Generalformula:C H

mallerMolecules(LessCarbonAtoms)LowerB.p

eC H

HigherB.p(MoreCarbon

omologousseriesA set of organic compounds in which the formula of each one differs from the previous one by an extra CH2- group of atoms.

embersinaHomologousSerieshave:

n 2n+2

S

1. MethaneCH42. Ethan 2 63. PropaneC3H84. ButaneC4H105. PentaneC5H126. HexaneC6H14

LargerMoleculesatoms)

H

M

.OH,COOH)

Samechemicalreactions Samefunctionalgroup(Eg Samegeneralformula DifferentPhysicalProperties!

#ReactionsofAlkanes

AlkanesreactwithChlorineinsubstitutionreaction(Slowreaction,requireslight)

Note:AlkanescanonlyundergocombustionreactionsandSubstitutionreactionwithchlorine!Otherwise,Alkanesisunreactive.

GAS

Liquid

Eachcarbonatomforms4bonds. Boilingpointincreasesasmoleculesgetlarger

Wh higherb.p?

y Intermolecularforcesofattractionbetween

esasmoleculesbecomelarger.moleculesincreas

HomologousseriesofAlkanes


47

16.2Alkenes

1) Alkenesareunsaturatedhydrocarbons(Theycanreactwithmanysubstancesinadditionreactions)forular:CnH2n

) AllalkenescontainC=Cdoublebonds

C2H4. PropeneC3H6

atoms)

2) General3

SmallerMolecules(LessCarbonAtoms)LowerB.p

7. MetheneCH28. Ethene910. ButeneC4H811. PenteneC5H1012. HexeneC6H12

LargerMoleculesHigherB.p(MoreCarbon

#ReactionsofAlkenes

1) Alkenesburninair(Combustion)ProduceCarbonDioxide&Water2 4 2 2+2H2O

uced!

C H +3O 2COIfincompletecombustion,Carbon(Soot)andcarbonmonoxidewillbeprod

*Additionreaction

C=Cdoublebondsarebroken,extraatomsareadded

2H4+Br2C2H4Br2Alkenes

colourisesifAlkeneispresent)

thatthecolourcanonlybepresentifremainssingle(Notreacted).

Ifitformsacompound,thecolourwilldisappear.Henceafterthereaction,orangebromine

2) AdditionofBromineC

Thisreactionisusedtotestfor(Orangebrominesolutionde

Info:BromineisfromGroup7,soithascolour.NoteBromine

turnscolourless.

GAS

HomologousseriesofAlkenes


48

3) AdditionofWaterAlkene+SteamAlcohol(RequirePhosporicAcidascatalyst,hightemperature&pressure)

lkene+HydrogenAlkane

4) AdditionofHydrogen(NickelCatalystisneeded)A

Thisreactionisusedtochangevegetableoiltomagarine.

16.3CrackingofAlkanes

CrackingA reaction in which big hydrogen molecules are broken into smaller molecules

1smallalkanemolecule1alkenemolecule

1) Alkanestrolforvehicles

) Hydrogen

by heat.

Donebypressingbigalkanemoleculesoverasolidcatalystathightemperature Products:

*Crackingofalkanesisusedtoproduce:

2) Morepe3


49

Chapter17Summary

ALCOHOLSANDORGANICACIDS17.1Alcohols

1. AlcoholsareorganiccompoundscontainingOHgroupofatoms.2. GeneralFormula:C H OH

Smaller oleculesLowerB.p

anolCH3OHEthanolC H OH

HigherB.p

dsofMakingEthanol:

Ethanol

n 2n+1

M

1. Meth2. 2 53. PropanolC H OH3 74. ButanolC H OH4 9

LargerMolecules

#Metho

Method1:

Ethene+Steam(Alkene) (Alcohol)

Cottonwooltopreventlossofliquid,allowsescapeofgas(CO2)

ConicalFlask

Warmwater(37oC)

AqueousGlucose& Yeast

Allalcoholsareliquids!

HomologousseriesofAlcohol


50

Method2

Fermentationofglucosewithyeast.

Theenzy toethanolmesinyeastchangeglucosein andCarbonDioxide

Reactionisbestat37oC(Ifhighertemp,enzymestructurewillbedamaged,nolongeractsascatalyst!)

Productsoffermentation:DilutesolutionofethanolPureethanolisobtainedbyfractionaldistillation.

#UsesofEthanol:

1. Solvents(Eg.Perfumes)2. Alcoholicdrinks(Beer/wine)3. ars)Fuel(Petrolforc

#Reactions

1) AlcoholburninairCarbonDioxide+Water

ofAlcohol

toProduce

organicacids

H OH+O CH3COOH+H2O(Lose2hydrogen,Gain1Oxygen=Oxidation!)

ctsascatalysttothereaction.

Eg.Ethanol+OxygenCarbonDioxide+Water

2) AlcoholsareoxidisedtoEg.Ethanol+OxygenEthanoicAcid+WaterC2 5 2

Bacteriainaira

ConditionsforFermentation:37oCEnzymesinyeastNoOxygenpresent


51

#17.2CarboxylicAcids1. CarboxylicAcidsOrganiccompoundsco2. GeneralFormula:CnH2n+1CO2H

ntainingCO2Hgroupofatoms.

kingformula:CnH2nO2onfusingformoststudents!Thenewformulais

proventoworkonallOlevelquestions!NoProbs!)

SmallerMoleculesLowe B.p

13. ethanoicAcidC1H2O214. thanoicAcidC2H4O215. ropanoicAcidC3H6O216. utanoicAcidC4H8O2

LargerMoleculesHigh

*Tip:Youshouldusethisalternatewor

(TheoriginalformulaCnH2n+1CO2Hmakesitveryc

r

MEPB

erB.p

#Acid+AlcoholEster+Water

mixture

littleconcentratedSulphuricAcidactsascatalyst.

Ethanoate.(Ester)

ReactionsofCarboxylicAcids

Boilthe A

Eg.EthanoicAcid+Ethanol Ethyl

#UsesofEsters:

1. Solvents2. Flavouringinfood

Liquid

Formulasgeneratedusingthisnewformula:

CnH2nO2

HomologousseriesofOrganicAcids

Estershavesweetsmell

Reactionofmaking

nEstersiscalledEsterificatio


52

Chapter18Summary

MACROMOLECULESger tested in Science (Chemistry) new 20 lla

r sendmeanemailtorequestforsummarizednotesonthistopic.Theupdatednoteswillthenbemadeavailableintheextversionofthisnotesseries.

ThePeriodicTableandFullChemistryequationsisattachedwiththis.zippackage.isrecommendedthatyouphotocopyextrasandpastethemontowallsofyourroomorevenwashrooms!Itllhelpyouto

mistakesonnotes?Sendmeanemail.Correctionswillbemadewithin2days.

copynotesforothersubjectsarealsoavailableathttp://www.rayrevision.webs.com

(Topic is skipped as it is no lon 08 sy

syllabus,

bus)Ifyouretakingpurescienceandthistopicisinyou

n

Itremember!

Found

*Hard

chemistry full

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