Chemistry Notes v16 Extra 11

OLevelSc(Chemistry)v1.6XtraShortSummarizedExamNotesYoushouldreadthroughthisbookletbeforeenteringtheexamhall!ThisbookletcontainsextranoteshavenotbeenincludedintheFullScienceChemistrySummarizednotes1.5booklet.SomeofthenotesmightbethedirectanswertoyourupcomingOLevelpaper!http://www.rayrevision.webs.comRAYNotes2009February2009AllRightsReserved
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Science(Chemistry)Summarizedversion1.6(ExtraExamNotesEdition)RAYNotes2009(Hardcopy)

RemembertodrawthisoutinChemistryexams!(Solubilitytablesfromyourtextbooksarehardertomemorise)

Soluble Insoluble Nitrate All -

Sulfate Rest Ba, Ca, Pb

Chloride Rest Ag, Pb

Carbonate Group1 Rest

Remembervia:BakedChickenPastaAtPastamania

SecretTablecontributedbyMsAida(BtVSS,MOESingapore)

Thistablehelpsyouknowwhetherasaltissolubleornot.

Below: Preview of the Modified Periodic Table.FullversionavailableforfreedownloadatRayrevision.webs.com


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.

TestingforANIONS:

ANION Testedwith

Observations

Chlorine AgNO3 AgCl White

ColourofObservationSolubleorInsolubleinexcessAlkali

Carbonate Acid CO2 CarbonDioxide(TurnLimewaterchalky)

Sulphate Ba(NO3) BaSO4 White

Nitrate Al,NaOH NH3 Ammonia(Turnredlitmusblue)

Iodide Pb(NO3)2 PbI2 Yellow


TestforGASES:

AmmoniaUsedamplitmusPaperTurnsfromredtoblue

CarbonDioxideUseLimewaterWhitepptformed(TurnsChalky)

ChlorineUseDampbluelitmuspaperBleachesLitmuspaper(LitmusTurnscolourless)

HydrogenUseBurningSplint'Pop'SoundHeard

OxygenUseGlowingSplintGlowsBrighterorBurstintoflames

SulphurDioxidePlaceadropofPotassiumDichromate(VI)onFilterpaperOrangeDichromateturnsgreen._________________________________________________________________________________

Mole Concept - Memorise this 4 IMPORTANT Formulas:

Massof

SampleVolumeof

Gas

No.of

Mole

No.of

Particles

No.of

MoleMolarMass

No.of

Mole 24dm36x1023

Mole

Volume Concentration


RandomNotes

SomePropertiesofAllacidicsolutions

1. Allacidschangebluelitmusred2. Acidsreactwithmetalswhichareabovehydrogeninthereactivityseries.3. Acidreactswithbasestoformsaltandwater.

UsesofAmmonia

1) Manufactureofnitricacid2) Usedtoproducefertilisers

Note:

Hydrogencanbeusedasafuel! Ehtene(Alkene)isusedtomakeplastic

PotassiumDichromate(VI)

Actsasanoxidisingagent. Ifsomethingisoxidised,itwillturnfromorangetogreen! UsedtotestforSulphurDioxidePlaceadroponfilterpaper,colourchangesfromorangetogreen.

*Note:PotassiumDichromateturnsfromOrangetogreenwhenAlcoholispresent!BecauseP.D,whichisanoxidisingagent,canoxidisealcoholintoorganicacid.AndP.Dturnsgreenwheneversomethingisoxidised.

PotassiumIodide

Actsasanreducingagent. Ifsomethingisreduced,itwillturnfromcolourlesstobrown!

(*orifanOxidisingagentispresent)

UsesofEthanol

1) Solventfororganiccompounds.2) Tomakealcoholicdrinks.

Note:Somethingthatcontainsmorecarboncontentisstronger!


SomeReactionrequirements:

1) Fermentation

37oC Enzymes NoOxygenpresent

2) Alkeneadditionofsteam,tobecomealcohol

Phosphoricacid(Catalyst) 300oC Hightemperature/pressure!

3) AlkeneadditionofHydrogen,tobecomeAlkane

NickelCatalyst

FractionalDistillationofPetroleum(Pleaseupdatepg43ofversion1.5withthisidealanswerbelow)

ImportantProcess(BetterAnswer):

1) Thecrudeoilisseparatedintodifferentfractionsbyfractionaldistillation2) Thecrudeoilisboiled.Eachfractionboilsatadifferenttemperature.3) Thesmaller,lightermoleculesseparateatlowboilingpoints.

Theheavierpartshavehigherboilingpoints.4) Thefractionsarerunofffromthefractionatingcolomnatdifferentboilingpoints.

GeneralLinks

ElecticalConductivityMovingIons

HeatConductivityFreeMovingelectrons

BoilingpointStrongelectrostaticattraction


WhyIonicgothighB.P?

1) Ioniccompoundsconsistentirelyofions.2) Theoppositechargedionsareheldclosetooneanotherbyverystrongelectrostatic

attraction,knownasionicbonds.3) Hencelargeamountofenergyisneededtobreakionicbonds;

Thereforehighboilingpoint.

WhyCovalentLowBP?

1) Covalentcompoundsconsistentirelyofmoleculesastheyareformedbysharingofelectrons.

2) Forcesbetweenmoleculesareveryweak.3) Henceonlysmallamountofenergyisneededtobreakbonds.

WhyIoniccompoundsconductinMolten/Aqueousstate?

Theionsbecomefreetomoveaboutandcanconveycharges.

#WhycannotconductinSolidstate?

Theionsarefixedrigidlybystrongelectrostaticattractionhencecannotconductelectricity.

WhyattachingMagnesiumtoundergroundpipeincreaseworkinglife?(AboutSacrificialProtectionPreventionofrusting)

Magnesiumisaboveironinthereactivityseries. WaterwillreactwithMagnesiuminsteadofiron,andMagnesiumgetswornout. Ironrustingismuchreduced. ThisisknownasSacrificialProtection

#WhycannotusecopperinsteadofMagnesium??

Copperisbelowironinthereactivityseries. HenceIronrustsfasterwhencopperisattachedtoiron.

WhyHydrogenMorereactive(thanHelium)?

Hydrogenhas1valenceelectron.Itcangainonemoretobecomestable. Heliumhas2valenceelectrons,makingitverystable.


PhysicalPropertiesofMetals

1. Goodconductorsofheatandelectricityusedtomakewires2. HighBp/Mpusedtomakecoolingutensils3. MalleableandDuctile.usedtomakejewellery

WhyisCopperrecycled?

1. Copperisexpensive2. Copperisnotseenasextensiveassomeothermetals.

NaminganEster

Whenyounameordrawthestructureofester,followthisFormula:

(DevelopedbyMsAida,BtVSSSingapore)

NOLmeansNameAlcoholFirst

NOLDAC

DACmeansDrawAcidFirst

SoinEthylPropanoate(Ester),theoneontheleftisAlcohol,rightisAcid.

PropanoicAcid(Acid)

Ethanol(Alcohol)

Butwhenyoudrawthechemicalstructure,theAcidpartmustbeontheleftside,Alcoholontherightside.

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3AmphotericOxides:

1. AluminiumOxide2. ZincOxide3. LeadOxide


OH O||COH

Whenyouseethisinachemicalstructure,itisanAcid

Whenyouseethisinachemicalstructure,itisanalcohol.

Alkane:CnH2n+2

Alkene:CnH2n

Alcohol:CnH2n+1OH

Acid:CnH2n+1CO2HORCnH2nO2

Thisnewformulaworksthesameastheoriginal!

Itishighlyrecommendedyouusethisformulatoavoidconfusions.

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Oxidation

1. GainOxygen2. LossHydrogen3. Losselectrons4. Increaseinoxidationstate

Reduction

1. Gainhydrogen2. Gainelectron3. LossOxygen4. Decreaseinoxidationstate

Note:Whencheckingifasomethingisoxidisedorreduced,usetheoxidationstatetocheck!Thisproduces100%Correctanswer.Ifyouchosetousethelose/gainofoxygenorelectrons,youranswermightnotbecorrect.


Proteinundergoeshydrolysistoformaminoacids!

Remember4alkalis(Solubleoxides/Hydroxides)

1. PotassiumHydroxide

2. SodiumHydroxideNaOH

3. CalciumHydroxideCa(OH)2

4. AmmoniaNH3

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ReactivitySeries:

1. Potassium

2. Sodium

3. Calcium

4. Magnesium

5. Aluminium

6. Zinc

7. Iron

8. Lead

9. Hydrogen

10. Copper

11. Silver

12. Gold

*Justrememberthephrase:

Playingsoccercanmakeallzappy,IloveHannacozshesgorgeous


MrofC60:(Carbonmolecule)

12x60=720

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Exothermic

Absorbenergy Breakbonds Absorbheat Testtubeturncold Eg.Icemeltingtowater(Absorbenergytobreakbonds)

Endothermic

Giveoutenergy BondForming ReleaseHeat Testtubeturnshot.

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Hydrogenusedasafuel

Etheneusedtomakeplastics

SolventsuitableforChromatography:Ethanol

__________________________________________________________________

ChemicalReactionsinBlastFurnace

1. Cokeburnsinairtoproducecarbondioxideandlotsofheat.C+O2 CO2

2. CarbonDioxidereactswithmorecoketoproduceCarbonMonoxide.C+CO2 2CO

3. CarbonMonoxidereactwithiron(III)Oxidetoproducemolteniron&carbondioxide.3CO+Fe2O3 3CO2+2Fe

4. Impuritiesinmoltenironareremovedbylimestone.CaCO3 CaO+CO2

5. CalciumOxideformedcombineswithSilicapresentintheoretoformslag,whichistappedout.CaO+SiO2 CaSiO3

#ImpurityinBlastFurnace:Silica


Process:Cracking

ALKANE STRONGHEAT ALKENE

Cracking A reaction in which big hydrogen molecules are broken into smaller molecules by heat.

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Group 7 - Halogens

Fluorine: Pale yellow gas Chlorine: Yellowish Green gas Bromine: Reddish Brown liquid Iodine: Black Solid Astatine: Black Solid

*DownloadtheModifiedPeriodicTableformorenotesonPeriodicTablehttp://www.rayrevision.webs.com

Note:whenBromineisaddedtoIodide,Gotreaction! Displacementreaction(BrominemorereactivethanIodide)

Forgroup7elements,themorereactiveelementswilldisplacethelessreactiveelementsinreactions.

Whyplasticcausepollution?

Itisnonbiodegradable

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DescribeatestforChlorine

Itturnsthebluelitmuspaperredfirstthenwhite.(Chlorinebleacheslitmuspaper)

HowtodistinguishwhichisAcid,whichisalcohol

Test:PutsomeSodiumCarbonateResultforAlcohol:NoreactionResultforAcid:Agasisreleased

BecauseAlcoholdoesnotreactwithcarbonate!

BecauseAcidcanreactwithcarbonateACID+CARBONATE SALT+WATER+CARBONDIOXIDEGAS
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UsesofNobleGases:

1. Helium:FillBaloons(LowDensity)2. Neon:LightTubes3. Argon:LightBulbs(unreactive)

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*Commonquestions:

DoesmetalliberatehydrogenfromDiluteHydrochloricAcid?

YesMorereactive NoLessreactive

Isthemetalreducedbyheatingwithcarbon?

YesLessReactive NoMoreReactive

HowdoescalciumionshowthatCalciumisametal?

Metalsformpositiveions.Calciumhas3valenceelectronsthusitisametal.________________________________________________________________

#Methodsofpreparingsalts

1) Titrationmethod(Formakingallgroup1salts)use:Soluble+Soluble

2) Formakingsolublesaltsnotfromgroup1,use:

Soluble+SolubleSoluble+Insoluble

3) PrecipitationMethodFormakingInsolublesalts,use:

Soluble+Soluble


Important:Memorisethestepsofpreparingsalts:TitrationMethod(SolubleBase+Acid)

ToprepareanysaltthatisfromGroup1.(Eg.PreparingSodiumSulfate)1) Add25cmofacidtoaconicalflask2) Addafewdropsofindicator.(eg.PhenolPhthalein)3) AddSodiumHydroxideusingaburetteuntilindicatorchangescolour.4) Repeatexperimentwith25cm3ofSulfuricAcidbutNOindicator!5) AddsamevolumeofSodiumHydroxide.6) SodiumSulfateisobtainedbyevaporating&crystalisingthesalt.

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PrecipitationMethod(Soluble+Soluble)

ToprepareanyInsolublesalt.1) Addsolublesaltwithsolublesalt.2) Filterouttheprecipitate.3) Washtheresiduewithdistilledwater.4) Leavetheresiduetodry.

***MUSTKNOWformulas:

Amonium NH4+

Ammonia NH3Hydroxide OHNitrate NO3

Carbonate CO3

2Sulfate SO4

2HydrochloricAcid HClSulfuricAcid H2SO4NitricAcid HNO3Oxygen O2SodiumChloride NaClCarbonDioxide CO2

Memorisethistemplate,andreplacetheunderlinedwordsduringexams!


Whyimportanttorecyclemetals?

1) Itcanhelpconservethemetaloresintheground,makingitlastlonger.2) Itsavesthemoneyneededforextractionofmetals.

_______________________________________________________________________

#Whypeopleconcentrateonrecyclingcopper?

Copperismorescarce,hencemoreexpensivethaniron.

AdvantagesofRecycling:

1. Metaloresinthegroundcanlastlonger.

2. Moneysavedinenergyneededtoextractnewmetalsfromore.

3. Scrapmetalisremovedfromtheenvironment,preventsland&waterpollutionduetocorrosion.

DisadvantagesofRecycling:

1. Expensivetocollectstrapmetalsfrommanysources

2. Metalfumesproducedinmeltingofscrapmetalscancausepollution._______________________________________________________________________

MembersofHomologousserieshave:

DifferentEmpiricalformula DifferentPhysicalProperties

Remember:Abaseisametaloxideorhydroxide!_____________________________________________________________________________

#Whichcompoundformsanacidicsolutionwithwater??

Ans:CarboxylicAcid(Acid+Water AcidicSolution)

*NotethatexcessAcidorAlkalicanpollutetheenvironment!!

Ifaquestionasksforthechemicalpropertiesofacid,avoidwritingItturnsbluelitmuspaperred writeacidreactswithbasetoform...


Effectsofacidrain

1) Corrodescementandstonesusedinbuildings2) Killsfishesinfreshwaterlakes.3) Makesagriculturallandacidicresultingincropsgrowingpoorly.

ImportantTip:

AnyquestionthatwantsyoutowritetheIonicEquationofanyneutralisationreaction,justwritethisout:

H++OH H2O___________________________________________________

Notethatsaltdonotreactwithacid!

Eg.Copper(II)NitratedonotreactwithSulphuricAcid

Salt

However,Copper(II)OxidewillreactwithSulphuricAcid!

+ Gotreaction

AcidBase

ChemicalPropertiesofGroup7elements

1) Allarediatomicmolecules.2) Allarecoloured.3) Allareoxidisingagents.4) Allarenonmetals.

PhysicalPropertiesofGroup7elements

1) TheyhavelowMp/BpTheyarepoorconductor

3) Theyarecolouredsubstances,colourbecomedarkerdownthegroup2) ofelectricity


oremoveSulphur

Ans:Use:

SlakedLimeciumHydroxide

tantNote:Isotopeshave:

Samechemicalproperties(Becozsameno.ofvalenceelectrons)ties

try,LimeisAlkaline!NOTsameasLEMON!!!

Ironsreactsrapidlyinsteam,slowlyincoldwater__________

Howt Dioxidefrom......??

Acidic

Cal

Impor

Differentphysicalproper

Info:Inchemis

________________________________________________________

Air

1%OtherGas(mainlyargon) 20%Oxygen 79%Nitrogen

Others:CO2,Water

oleumFractionsractionalDistillationofPetroleumprocessatPg7)

1. Petroleum Cylindergasforcooking

Kerosene(Paraffin) JetfuelDiesel FuelforLubricatingOilBitumen Surfacing

Vapour

Petr (F

2. Petrol Fuelforcars3. Naptha MakingChemicals4. 5. bus6. Wax,Polishes,Lubricants7. roads


articlesTheory

Mustmemorisethefollowing:

P

#Factorsaffectingspeedofreaction

1) Concentrationofsolution

tion,thefastertherateofreaction.

ertogethersotheycollidemorefrequently

________________________

ressure

ThehighertheconcentrationofsoluBecausetheparticlesareclosandsothereweremorefrequentreactions.Note:Onlyappliestoreactionsofsolutions._____________________________________

2) P

heparticlesaresqueezedclosertogether,sotheycollidemore

_______________

articlesizeofsolid

Thehigherthepressure,thhigheristherateofreaction.Becausetfrequentlyandsothereweremorefrequentreactions.Note:Onlyappliestoreactionsofgases.______________________________________________

3) P

ceareaofthesolidincreasessoreactingparticles

dsotheremorefrequentreactions.

____________________________________

emperature

Thesmallertheparticlesize,thehighertherateofreaction.BecausethetotalsurfaofliquidandgasescollidemorefrequentlywiththesurfaceanareNote:Onlyappliestoreactionsofsolids._________________________

4) T

ertemperature,theparticleshavegreaterkineticenergy,

Thehigherthetemperature,thefastertherateofreaction.Becauseathighsotheyreactmoreoftenwhentheycollide.


VeryReactiveMetals

For:

(Decomposingmetalcompoundwithelectricity) PotassiumSodiumCalciumMagnesium

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ModeratelyReactiveMetals

ZincIronLead

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LowReactivityMetals

CopperSilver

v1.6booklet)

Foundmistakesonnotes?Sendmeanemail.Correctionswillbemadewithin2days.

*Hardcopynotesforothersubjectsarealsoavailablea http://www.rayrevision.webs.com

*MethodsofextractionThemethoduseddependsonhowreactiveisthemetals!

Electrolysis

Aluminium

Heatingmetaloxidewithcoke For:

______________________________

Heatingmetalcompoundsinair For:

(Endofexamnotes

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Chemistry Notes v16 Extra 11

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