2016 chemistry written examination 2 · pdf filechemistry written examination tuesday 8...

CHEMISTRYWritten examination

Tuesday 8 November 2016 Reading time: 9.00 am to 9.15 am (15 minutes) Writing time: 9.15 am to 11.45 am (2 hours 30 minutes)

QUESTION AND ANSWER BOOK

Structure of bookSection Number of

questionsNumber of questions

to be answeredNumber of

marksA 30 30 30B 11 11 90

Total 120

• Studentsarepermittedtobringintotheexaminationroom:pens,pencils,highlighters,erasers, sharpeners,rulersandonescientificcalculator.

• StudentsareNOTpermittedtobringintotheexaminationroom:blanksheetsofpaperand/orcorrectionfluid/tape.

Materials supplied• Questionandanswerbookof44pages.• Databook.• Answersheetformultiple-choicequestions.Instructions• Writeyourstudent numberinthespaceprovidedaboveonthispage.• Checkthatyourname andstudent numberasprintedonyouranswersheetformultiple-choice

questionsarecorrect,andsignyournameinthespaceprovidedtoverifythis.• Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.• AllwrittenresponsesmustbeinEnglish.At the end of the examination• Placetheanswersheetformultiple-choicequestionsinsidethefrontcoverofthisbook.• Youmaykeepthedatabook.

Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.

©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2016

SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education 2016

STUDENT NUMBER

Letter

2016CHEMISTRYEXAM 2

SECTION A – continued

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eaQuestion 1

Whichoneofthefollowinglistscontainsonlyanalyticaltechniquesthatcanbeusedtodeterminetheconcentrationofasubstance?A. AAS,GCandHPLCB. HPLC,GCandTLCC. UV-visand1HNMRD. UV-vis,AASandTLC

Question 2

H HC

H

CH C C C H

H HH H

H

H

H

HHH

C

C HH

C

H

HH

C

Whatisthecorrectsystematicnameforthecompoundshownabove?A. 4-methyl-5-ethylhexaneB. 2-ethyl-3-methylhexaneC. 4,5-dimethylheptaneD. 3,4-dimethylheptane

SECTION A – Multiple-choice questions

Instructions for Section AAnswerall questionsinpencilontheanswersheetprovidedformultiple-choicequestions.Choosetheresponsethatiscorrect orthatbest answers thequestion.Acorrectanswerscores1;anincorrectanswerscores0.Markswillnotbedeductedforincorrectanswers.Nomarkswillbegivenifmorethanoneansweriscompletedforanyquestion.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.

3 2016CHEMISTRYEXAM

SECTION A – continuedTURN OVER

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Question 3Hydrogenperoxidesolutionsarecommerciallyavailableandhavearangeofuses.Theactiveingredient,hydrogenperoxide,H2O2,undergoesdecompositioninthepresenceofasuitablecatalystaccordingtothereaction

2H2O2(l) →2H2O(l)+O2(g)

Inthisreaction,oxygenA. onlyundergoesoxidation.B. onlyundergoesreduction.C. undergoesbothoxidationandreduction.D. undergoesneitheroxidationnorreduction.

Question 4Apaperchromatographoffourdyes,G,P,RandY,isshownbelow.

solvent front

origin

G P R Ydye

20191817161514131211109876543210

TheRfvalueofthedyemoststronglyadsorbedontothestationaryphaseisA. 0.25B. 0.33C. 0.75D. 0.78

2016CHEMISTRYEXAM 4


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Question 5Apieceofdouble-strandedDNAis300basepairsinlength.Itcontains180guaninebases.Thenumberofthymineandcytosinebases,respectively,isA. 120and120B. 120and180C. 180and120D. 180and180

Question 6Asolutionofapproximately0.1Mbenzoicacid,C6H5COOH,istitratedagainsta0.1004M solutionofsodiumhydroxide,NaOH.WhichoneofthefollowingpHcurvesrepresentsthistitration?

25volume of NaOH (mL)

14

7pH

025

volume of NaOH (mL)

14

7pH

0

25volume of NaOH (mL)

14

7pH

025

volume of NaOH (mL)

14

7pH

0

A. B.

C. D.

5 2016CHEMISTRYEXAM


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Use the following information to answer Questions 7 and 8.Agroupofstudentswasrequiredtodeterminetheconcentrationofasolutionofhydrochloricacid,HCl,providedforatitrationcompetition.Ineachtitration,a25.00mLaliquotofafreshlystandardisedsolutionof0.2450Msodiumhydroxide,NaOH,waspipettedintoaconicalflaskandtitratedagainsttheHClsolution.Anappropriateindicatorwasadded.Theexperimentwasrepeateduntilthreeconcordantresultswereobtained.Thedataforthesetitrationsisshowninthefollowingtable.

volumeofaliquotofNaOH 25.00mL

concentrationofNaOHsolution 0.2450M

meantitreofHClsolution 13.49mL

Question 7Basedontheseresults,theconcentrationofHClisA. 0.1322MB. 0.4540MC. 1.322MD. 2.202M

Question 8TheexperimentalvalueoftheconcentrationofHClobtainedfromthesetitrationswaslessthantheactualvalue.Whichoneoftheseactionsbythestudentsmostlikelyaccountsforthelowerthanexpectedresult?A. rinsingtheburettewithwaterB. rinsingthepipettewithwaterC. rinsingtheconicalflaskwithwaterD. leavingthefunnelinthetopoftheburette

Question 9ThemostsuitableindicatorforatitrationofNaOHagainstbenzoicacid,C6H5COOH,isA. bromophenolblue.B. methylorange.C. thymolblue.D. phenolred.

2016CHEMISTRYEXAM 6


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Question 10Astudentcalibratedacalorimeterusinganelectricheatingcoil.Acurrentof1.50Awithapotentialdifferenceof4.50Vwasappliedfortwo-and-a-halfminutes.Adigitalproberecordedatemperatureriseof5.35°C.Thevalueofthecalibrationfactor,inJ°C–1,isA. 189B. 42.1C. 3.15D. 0.317

Question 11Met-enkephalin(Tyr–Gly–Gly–Phe–Met)isapeptidefoundinthecentralnervoussystemandthegastrointestinaltractofthehumanbody.Whichofthefollowingarethecorrectstructuresforthetwoterminalendsofmet-enkephalinataverylowpH?

A. –NH2 –COOH

B. –NH2 –COO–

C. –NH3+ –COO–

D. –NH3+ –COOH

Question 12Acondensationreactioninvolving200glucosemolecules,C6H12O6,resultsinapolysaccharide.Themolarmass,ingmol–1,ofthepolysaccharideisA. 36000B. 35982C. 32418D. 32400

7 2016CHEMISTRYEXAM


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Question 13Achemicalreactionhasthefollowingenergyprofile.

250

200

150enthalpy

(kJ mol–1)100

50

0

reactants

products

Theenthalpychangeoftheforwardreaction,inkJmol–1,isA. –170B. –80C. +70D. +240

2016CHEMISTRYEXAM 8


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Use the following information to answer Questions 14–16.Achemistinjected0.10molcarbonmonoxidegas,CO,and0.20molchlorinegas,Cl2,intoapreviouslyevacuatedandsealed1.0Lflask.Atthatinstant,thefollowingreactionbegantooccur.

CO(g)+Cl2(g)⇌COCl2(g) H=–108kJmol–1

Theconcentrationsofthethreespeciespresentintheflaskweremonitoredovertime.Theflaskwasheldataconstanttemperature.Thefollowingconcentration–timegraphwasobtained.

0.2

concentration(mol L–1)

0.1

01 2 3 4

time (minutes)5 6

Cl2COCOCl2

Key

Question 14Themostlikelysuddenchangemadetothesystematthetwo-minutemarkwouldbethatA. acatalystwasinjectedintotheflask.B. thevolumeoftheflaskwasincreased.C. aninertgaswasinjectedintotheflask.D. someofthegasmixturewasremovedfromtheflask.

Question 15ThemagnitudeoftheequilibriumconstantforthereactionatthetemperatureoftheexperimentisA. 0.15B. 1.4C. 3.0D. 6.7

9 2016CHEMISTRYEXAM


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Question 16Iftheequilibriumsystemweresuddenlyheatedatconstantvolumeatthefive-minutemark,whichoneofthefollowingchangeswouldresult?A. TheconcentrationofCOCl2wouldincrease.B. Thetotalgaspressureintheflaskwoulddecrease.C. Theequilibriumconstantforthereactionwouldincrease.D. Thetotalnumberofgasmoleculesintheflaskwouldincrease.

Question 17Thecombustionofhexanetakesplaceaccordingtotheequation

C6H14(g)+192O2(g)→6CO2(g)+7H2O(g) ΔH=–4158kJmol–1

Considerthefollowingreaction.

12CO2(g)+14H2O(g)→2C6H14(g)+19O2(g)

ThevalueofΔH,inkJmol–1,forthisreactionisA. +8316B. +4158C. –2079D. –3568

Question 18Themoleculewiththestructuralformulashownbelowreactswithhydrogenbromide,HBr,toformC5H11Br.

H

H

HH

HH H

H

CC

H

CC

C

H

ThenumberofdifferentstructuralisomerstheoreticallypossibletobeproducedbythisreactionisA. 1B. 2C. 3D. 4

2016CHEMISTRYEXAM 10


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Question 19Anelectroplatingprocessusesasolutionofchromium(III)sulfate,Cr2(SO4)3,todepositathinlayerofchromiumonthesurfaceofanobject.Acurrentof5.00Aismaintained.Howlongdoesittake,inseconds,todeposit0.0192molchromiumontothesurface?A. 371B. 1110C. 1860D. 5570

Question 20Howdoesdilutinga0.1Msolutionoflacticacid,HC3H5O3,changeitspHandpercentageionisation?

pH Percentage ionisation

A. increase decrease

B. increase increase

C. decrease increase

D. decrease decrease

Question 21TheammoniumionNH4

+actsasaweakacidaccordingtotheequation

NH4+(aq)+H2O(l)⇌NH3(aq)+H3O+(aq)

The[H3O+]ofa0.200MammoniumchloridesolutionisclosesttoA. 4.79×10–6MB. 9.55×10–6MC. 1.06×10–5MD. 1.51×10–5M

11 2016CHEMISTRYEXAM


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Question 22WhenetheneismixedwithchlorineinthepresenceofUVlight,thefollowingreactiontakesplace.

CH2CH2(g)+Cl2(g)UV light

CH2ClCH2Cl(l)

Reactionsoforganiccompoundscanbeclassifiedinanumberofways.Thefollowinglistshowsfourpossibleclassifications:1. addition2. substitution3. redox4. condensation

Whichclassification(s)appliestothereactionbetweenetheneandchlorine?A. 1B. 1and2C. 1and3D. 4

Question 23SubstancePisapeptidefoundinthehumanbody,anditisassociatedwithinflammationandpain.ThestructureofSubstancePisshownbelow.

H2N C C N

NH2

C C N C C N C C N C

H H H H H H H H H

C

CH2 O CH3 O H O CH2 O CH2

CH2

CH2

NH

COH

HN

O

OH

Whataretheabbreviatednamesofthetwocircledaminoacidresidues?A. ArgandPheB. LysandTyrC. PheandTyrD. MetandArg



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Question 24Methanolisaliquidfuelthatisoftenusedinracingcars.Thethermochemicalequationforitscomplete combustionis

2CH3OH(l)+3O2(g)→2CO2(g)+4H2O(l) ΔH =–1450kJmol–1

Octaneisaprincipalconstituentofpetrol,whichisusedinmanymotorvehicles.Thethermochemicalequationforthecompletecombustionofoctaneis

2C8H18(l)+25O2(g)→16CO2(g)+18H2O(l) ΔH =–10900kJmol–1

Themolarmassofmethanolis32gmol–1andthemolarmassofoctaneis114gmol–1.Whichoneofthefollowingstatementsisthemostcorrect?A. Burningjust1.0gofoctanereleasesalmost96kJofheatenergy.B. Burningjust1.0gofmethanolreleasesalmost23kJofheatenergy.C. Octanereleasesalmosteighttimesmoreenergyperkilogramthanmethanol.D. Theheatenergyreleasedbymethanolwillnotbeaffectediftheoxygensupplyislimited.

Question 25AclassofChemistrystudentsinvestigatedthereactionofcoppermetalandiodinesolution.Aftermakingpredictionsaboutthereaction,theyplacedacopperstripintoaniodinesolutionandcomparedtheirpredictionswiththeirobservations.Anumberofgroupsrecordedthefollowing.

Reactants Prediction Observation over 10 minutes

Cumetal + I2solution

Areactionshouldoccur.TheexpectedproductsareCu2+andI–.ThesolutionshouldturnfrombrowntoblueasI2isconsumedandCu2+isformed.TheCumetalshouldlookcorroded.

noapparentchange

Thepredictedresultswerenotobserved.Theclasswasaskedtosuggestsomehypothesestoexplaintheunexpectedresult.Whichoneofthefollowinghypothesescouldnotexplaintheunexpectedresult?A. Thereactionratemighthavebeentooslowforthetimeallowed.B. Anequilibriumwasestablishedand[Cu2+]wastoolowtobevisible.C. Abrominesolutionwasaccidentallyusedinplaceoftheiodinesolution.D. Thesurfaceofthecoppermetalwasgreasy.



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Question 26Dilutenitricacidreactswithanhydroussodiumcarbonatetoproducecarbondioxidegas.

2HNO3(aq)+Na2CO3(s)→2NaNO3(aq)+CO2(g)+H2O(l)

Inanexperiment,0.142molanhydrousNa2CO3powderwasaddedtoexcessHNO3insolution,ina2.00Lreinforced,sealed,metalvessel.Pressureandtemperaturesensorswereusedtomonitorthereaction.Thevesselwasinitiallyat101.3kPaand22.0°C.Whenthereactionwascomplete,thefinaltemperaturewas24.1°C.Whatistheadditionalpressure,inkPa,insidethevesselduetothecarbondioxidegasafterthecompletionofthereaction?(Assumethatthevolumeofthesolutioninthevesselisnegligible.)A. 349B. 175C. 28.3D. 14.2



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Question 27Astudentsetupanexperimenttotesttheeffectofdifferentfactorsontherateandextentofthereactionbetweenastrongacidandmarblechips(calciumcarbonate,CaCO3).Ineachtrial,themassoftheflaskanditscontentswasmeasuredevery30seconds,fromtheinstantthereactantsweremixed.

Trial 1Thestrongacidusedwashydrochloricacid,HCl.Theequationforthereactionisasfollows.

2HCl(aq)+CaCO3(s)→CaCl2(aq)+CO2(g)+H2O(l)

CO2

plug of cottonwool

100 mL 0.5 M HCl20 g marble chips

digital scales

Trial 2Onechangetothereactionconditionswasmadeandtheexperimentwasrepeated.

Theresultsofthetwotrialsweregraphedonthesameaxesandareshownbelow.

Trial 1

Trial 2mass of flask (g)

time (seconds)

InTrial2,thestudentmusthaveA. heatedthe0.5MHClbeforeaddingittotheflask.B. doubledthevolumeof0.5MHCladdedtotheflask.C. used100mLof0.5MH2SO4insteadof100mLof0.5MHCl.D. usedthesamemassofmarblebutcrusheditintoapowder.



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Question 28 Ateamofchemistswasinvestigatingthefollowingequilibriumreaction.

H2(g)+I2(g)⇌2HI(g) ΔHisnegative.

Hydrogengas,H2,andiodinegas,I2,wereinjectedintoasealedcontainerandthemixturewasallowedtoreachequilibrium.TheeffectofthefollowingchangesontheamountofHIwasmeasured:1. MoreH2gaswasinjectedintothecontainerataconstanttemperatureandvolume.2. Thetemperatureofthegaseswasdecreasedataconstantvolume.3. Someargongas,Ar,wasinjectedintothecontainerataconstanttemperatureandvolume.4. Thevolumeofthecontainerwasdecreasedataconstanttemperature.

Whichchange(s)wouldhaveresultedintheformationofagreateramount,inmol,ofHI?A. 1and2onlyB. 1,2and4onlyC. 3onlyD. 1and4only


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END OF SECTION A

Use the following information to answer Questions 29 and 30.Thefollowingdiagramshowsagalvaniccellthatissetupinauniversitylaboratory.

H2 gas (1 atm, 25 °C)

1 M H+ solution (25 °C)colourless

bubbles ofH2 gas

platinum electrode coatedwith tiny crystals of platinum

solid Fe rod

1 M Fe2+ solution (25 °C)pale green

salt bridge

Thehalf-cellontherightiscalledthestandardhydrogenelectrode(SHE).Itisthestandardagainstwhichallstandardredoxpotentialsarecompared.Hydrogengas,H2,iscontinuallybubbledintothishalf-cell.

Question 29Whichoneofthefollowingwouldoccurattheplatinumelectrodewhenthecelldischarges?A. Electronswouldmovefromtheplatinumelectrodethroughtheacidsolutiontowardsthesaltbridge.B. Theplatinumelectrodewouldactastheanodeinthiscellandhavepositivepolarity.C. ThepHofthesolutionsurroundingtheplatinumelectrodewouldincrease.D. Thehydrogengaswouldbeoxidisedattheplatinumelectrode’ssurface.

Question 30WhatisonechangethatwouldbeexpectedintheFe2+/Fehalf-cellasthecelldischarges?A. Crystalsofplatinumwouldbedepositedonthesurfaceoftheironelectrode.B. TheFe2+solutionwouldstartbubblingatthesurfaceoftheelectrode.C. Crystalsofironwouldbedepositedonthesurfaceoftheironelectrode.D. TheFe2+solutionwouldbecomeadarkergreencolour.


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SECTION B – continuedTURN OVER

SECTION B

Instructions for Section BAnswerallquestionsinthespacesprovided.Writeusingblueorblackpen.Toobtainfullmarksforyourresponses,youshould:• givesimplifiedanswers,withanappropriatenumberofsignificantfigures,toallnumericalquestions;

unsimplifiedanswerswillnotbegivenfullmarks• showallworkinginyouranswerstonumericalquestions;nomarkswillbegivenforanincorrectanswer

unlessitisaccompaniedbydetailsoftheworking• makesurechemicalequationsarebalancedandthattheformulasforindividualsubstancesincludean

indicationofstate;forexample,H2(g),NaCl(s).Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.


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SECTION B – continued

Question 1 (5marks)Aperfumewasanalysedusingagaschromatograph.Asimplifiedsectionoftheresultingchromatogramisshownbelow.ThefourpeakscorrespondtocompoundsP,Q,RandS.

detectorsignal

PQRS

10 20 30 40 50time (seconds)

60 70 80 90 100

a. Whatistheretentiontime,Rt,ofCompoundQ? 1mark

b. Allfourofthecompounds,P,Q,RandS,arefromthesamefamilyoforganiccompounds.

Whichofthesefourcompoundswouldhavethehighestmolecularmass?Statetheevidenceused. 2marks

Compound

Evidence

c. Usingthesameinstrumentonanotheroccasion,itwasfoundthatthechemicallimonenehadaretentiontimeof53seconds.

Canitbeconcludedthatlimoneneisoneofthecompoundsintheperfumeunderanalysis?Justifyyouranswer. 2marks


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Question 2 (6marks)Acommonironore,fool’sgold,containsthemineralironpyrite,FeS2.Typically,thepercentagebymassofFeS2inasampleoffool’sgoldisbetween90%and95%.Theactualpercentageinasamplecanbedeterminedbygravimetricanalysis.ThesulfurinFeS2isconvertedtosulfateions,SO4

2–.Thisisthenmixedwithanexcessofbariumchloride,BaCl2,toformbariumsulfate,BaSO4,accordingtotheequation

Ba2+(aq)+SO42–(aq)→BaSO4(s)

Whenthereactionhasgonetocompletion,theBaSO4precipitateiscollectedinafilterpaperandcarefullywashed.Thefilterpaperanditscontentsarethentransferredtoacrucible.Thecrucibleanditscontentsareheateduntilconstantmassisachieved.Thedataforananalysisofamineralsampleisasfollows.

initialmassofmineralsample 14.3g

massofcrucibleandfilterpaper 123.40g

massofcrucible,filterpaperanddryBaSO4 174.99g

M(FeS2) 120.0gmol–1

M(BaCl2) 208.3gmol–1

M(BaSO4) 233.4gmol–1

a. CalculatethepercentagebymassofFeS2inthismineralsample. 5marks

b. Stateoneassumptionthatwasmadeincompletingthecalculationsforthisanalysis. 1mark


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SECTION B – Question 3–continued

Question 3 (9marks)Thediagrambelowrepresentsacertainbiomolecule.

H

C

C

C

H

O

O

O

O

O

O

C

C

C

(CH2)11CHCH(CH2)7CH3



H

H

H

a. Nametheclassoforganicbiomoleculestowhichthebiomoleculeabovebelongs. 1mark

Thisbiomoleculecanbehydrolysedtoformglycerolanderucicacid,afattyacid.Erucicacidisclassifiedasmonounsaturated.

b. Explainwhyerucicacidisclassifiedasmonounsaturated. 1mark

Erucicacidcanbeextractedfromplants.Itcanreactwithmethanoltomakemethylerucate,whichcanbeusedasthebiofuelknownasbiodiesel.

c. Writethesemi-structuralformulaofmethylerucate. 1mark

d. Describeoneenvironmentaladvantageofusingbiodieselasafuelratherthanpetrodiesel,whichisproducedfromcrudeoil. 2marks


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e. Ethanolisanotherbiofuel.Itcanbeproducedbythefermentationofsugarsinplantmaterial.

i. Writeabalancedchemicalequationforthefermentationofglucose. 1mark

ii. Theethanolproducedcanbeseparatedfromthereactionmixturebydistillation.

Whatwouldbetheminimummassofpureglucoseneededtoproduce1.00Lofpureethanolfromfermentation?

d(C2H5OH)=0.785gmL–1 3marks


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Question 4 (10marks)Abottlecontaininganunknownorganiccompoundwasexaminedinauniversitylaboratory.Therewasanincompletelabelonthebottlethatgaveonlytheempiricalformulaforthecontents:CH4N.Achemisthypothesisedthattheunknowncompoundwas1,2-ethanediamine,NH2CH2CH2NH2.

a. Massspectrometryproducedthefollowingspectraldata.

100

80

60

40

relativeintensity

20

010 15 20 25 30 35

m/z40 45 50 55 60

Mass spectrum

Data:SDBSWeb,http://sdbs.db.aist.go.jp, NationalInstituteofAdvancedIndustrialScienceandTechnology

i. Onthediagramabove,circlethebasepeak. 1mark

ii. Atwhatm/zratioistheprincipalpeakthatsupportsthechemist’shypothesisthattheunknowncompoundhastheformulaNH2CH2CH2NH2?Justifyyouranswer. 2marks

iii. Writethesemi-structuralformulaofthespeciesthatproducesthepeakat30m/z. 1mark


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SECTION B – Question 4–continuedTURN OVER

Infrared(IR)spectroscopywasalsousedtoanalysethesample.Thespectrumisshownbelow.

100

50

0

transmittance (%)

4000 3000 2000wave number (cm–1)

1500 1000 500

IR spectrum


b. IsthisspectrumconsistentwiththeunknowncompoundbeingNH2CH2CH2NH2?UseevidencefromtheIRspectruminyourresponse. 2marks


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SECTION B – Question 4 –continued

Thesamplewasalsoanalysedusing13CNMR.Thespectrumisshownbelow.

13C NMR spectrum

200 180 160 140 120 100ppm

80 60 40 20 0


c. Isthe13CNMRspectrumconsistentwiththestructureofNH2CH2CH2NH2?Justifyyouranswer. 2marks


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d. NH2CH2CH2NH2formsacondensationpolymerwithbutanedioicacid,HOOCCH2CH2COOH.

Drawthestructureoftherepeatingunitonthecopolymerthatwouldbeformed. 2marks


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Question 5 (12marks)Bromomethane,CH3Br,isatoxic,odourlessandcolourlessgas.Itisusedbyquarantineauthoritiestokillinsectpests.Asimplifiedreactionforitssynthesisis

CH3OH(g)+HBr(g)⇌CH3Br(g)+H2O(g) ΔH=–37.2kJmol–1at298K

Themanufacturerofthischemicalinvestigatesreactionconditionsthatcouldaffectthetimetheprocesstakesandthepercentageyield.

a. Predicttheeffectofeachchangegivenbelowontherateofproductionofbromomethaneandcircleyourprediction(increase,nochangeordecrease).Giveyourreasoning. 4marks

• Increasingtemperature(constantvolume)

increase nochange decrease

Reasoning

• Increasingpressure(constanttemperature)


Reasoning


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b. Consideringthesystematequilibrium,predicttheeffectofeachchangegivenbelowonthepercentageyieldofbromomethaneandcircleyourprediction(increase,nochangeordecrease).Giveyourreasoning. 4marks

• Increasingpressure(constanttemperature)


Reasoning

• ContinuouslyremovingtheproductCH3Br(constantvolumeandtemperature)


Reasoning


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SECTION B – continued

c. ThegraphbelowrepresentstheconcentrationofthreeofthespeciesinvolvedintheproductionofCH3Brwhentheyareatequilibriumatconstanttemperature.Attimet1,asmallamountofHBrwassuddenlyaddedtotheequilibriummixture.

Completethegraphaftert1,showingthechangesinconcentrationforeachofthethreespecies. 3marks

CH3Br

HBr

CH3OH

concentration(mol L–1)

t1time (seconds)

d. Whenbromomethaneisusedbyquarantineofficers,itispumpedintoasealedroomthatcontainstheitemstobetreated.

Describeonesafetyprecautionthatquarantineofficerswouldneedtoconsiderwhenusingbromomethane. 1mark


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CONTINUES OVER PAGE


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Question 6 (6marks)Brassisanalloyofcopperandzinc.Todeterminethepercentageofcopperinaparticularsampleofbrass,ananalystpreparedanumberofstandardsolutionsofcopper(II)ionsandmeasuredtheirabsorbanceusinganatomicabsorptionspectrometer(AAS).Thecalibrationcurveobtainedisshownbelow.

0.6

0.5

0.4

0.3absorbance

0.2

0.1

00 1 2 3

Cu2+ concentration (g L–1)4 5 6

a. A0.198gsampleofthebrasswasdissolvedinacidandthesolutionwasmadeupto100.00mLinavolumetricflask.Theabsorbanceofthistestsolutionwasfoundtobe0.13

Calculatethepercentagebymassofcopperinthebrasssample. 3marks


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b. Iftheanalysthadmadeupthesolutionofthebrasssampleto20.00mLinsteadof100.00mL,wouldtheresultoftheanalysishavebeenequallyreliable?Why? 2marks

c. Nameanotheranalyticaltechniquethatcouldbeusedtoverifytheresultfrompart a. 1mark


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Question 7 (8marks)a. Butanoicacidisthesimplestcarboxylicacidthatisalsoclassifiedasafattyacid.Butanoicacidmay

besynthesisedasoutlinedinthefollowingreactionflowchart.

But-1-ene

Reagent(s)

Name:

Structural formula:

Butanoic acidSemi-structural formula:

H+/Cr2O72– (aq)

Compound Y

i. Drawthestructuralformulaofbut-1-eneintheboxprovided. 1mark

ii. Statethereagent(s)neededtoconvertbut-1-enetoCompoundYintheboxprovided. 1mark

iii. WritethesystematicnameofCompoundYintheboxprovided. 1mark

iv. Writethesemi-structuralformulaofbutanoicacidintheboxprovided. 1mark

v. Writeabalancedhalf-equationfortheconversionofCr2O72–toCr3+. 2marks

33 2016 CHEMISTRY EXAM

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b. An incomplete reaction pathway for the synthesis of aspirin is given below.

i. Draw the structural formula of salicylic acid in the box provided. 1 mark

ii. The structural formula of the other reactant is provided.

State its systematic name in the box provided. 1 mark

+

Structural formula: Structural formula:

Name: salicylic acid Name:

conc. H2SO4

Aspirin

O

O

OHO

O

O O

H3C CH3

C

CCH3

C C


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Question 8 (7marks)Thelithium-ionbatteryisasecondarycellthatisnowwidelyusedinportableelectronicdevices.Inthesebatteries,lithiumions,Li+,movethroughaspecialnon-aqueouselectrolytebetweenthetwoelectrodes.Thebatteriesarehousedinsealedcontainerstoensurethatnomoisturecanenterthem.Bothelectrodesaremadeupofmaterialsthatallowthelithiumionstomoveintoandoutoftheirstructures.TheanodeconsistsofLiC6,wherelithiumisembeddedinthegraphitestructure.Lithiumcobaltoxide,LiCoO2,iscommonlyusedasthematerialinthecathode.Thereactionatthecathodeisquitecomplex.Whenthecelldischarges,Li+ionsmoveoutoftheanodeandenterthecathode.Duringdischarge,thehalf-cellreactionattheanodeis

LiC6 →Li++e–+C6

a. Duringdischarge,whatisthepolarityofthegraphiteelectrode? 1mark

b. Writethehalf-equationforthereactionthatoccursatthecathodeofalithium-ionbatterywhenitisrecharged. 1mark

c. Inalithium-ionbattery,lithiummetalmustnotbeincontactwithwater.

Explainwhyandjustifyyouranswerwiththeuseofappropriateequations. 3marks


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d. Identifyonedesignfeatureofthelithium-ionbatterythatenablesittoberecharged. 1mark

e. Whatisoneadvantageofusingasecondarycellcomparedtousingafuelcell? 1mark


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Question 9 (8marks)Standardsolutionsofsodiumhydroxide,NaOH,mustbekeptinairtightcontainers.ThisisbecauseNaOHisastrongbaseandabsorbsacidicoxides,suchascarbondioxide,CO2,fromtheairandreactswiththem.Asaresult,theconcentrationofNaOHischangedtoanunknownextent.

a. CO2intheairreactswithwatertoformcarbonicacid,H2CO3.ThiscanreactwithNaOHtoformsodiumcarbonate,Na2CO3.

i. WriteabalancedoverallequationforthereactionbetweenCO2gasandwatertoformH2CO3. 1mark

ii. WriteabalancedequationforthecompletereactionbetweenH2CO3andNaOHtoformNa2CO3. 1mark

b. A10.00Lcontaineriscompletelyfilledwithafreshlymade0.1000MNaOHsolution. DuringaChemistryclass,9.90Lofthesolutionisusedandairenterstheemptyspaceabovethe

remainingsolutionbeforethecontaineriscompletelysealedofffromtheoutsideair. Thecontaineristhenopened.Airentersthecontainerat101.3kPaand21.5°C.Assumethatthe

concentrationofCO2intheairis0.0400%(v/v).

air

0.1000 M NaOH10.00 L container

i. CalculatetheamountofCO2,inmol,thatenteredthecontainer. 2marks


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ii. CalculatetheamountofNaOH,inmol,thatwouldbepresentinthesolutionthatremainsinthecontainer.AssumethattheNaOHdidnotreactwiththeCO2intheairthatenteredwhenthecontainerwasopened. 1mark

iii. Thecontaineristhenshakenthoroughly,ensuringthatalltheCO2intheairisabsorbedintothesolution.

CalculatetheresultingconcentrationofNaOHinthesolutioninthecontainer. 3marks


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Question 10 (12marks)AseniorChemistrystudentboughtapacketofKrispyKrackersfromthelocalfarmers’market.Thelabelonthepackethadnoinformationontheenergycontentofthebiscuits.ThestudentdecidedthathewouldmeasuretheenergycontentofaKrispyKrackersbiscuitbyburningitunderacanofwaterandmeasuringthetemperatureriseofthewater.Havingperformedasimilarexperimentinclass,heknewthatwhenthebiscuitwasburnt,heatenergywouldbelosttotheenvironment.Toincreasetheaccuracyoftheresult,somebutanegasfromabutanecanisterwasfirstburntandthetemperatureriseofthewaterfromthatwasmeasured.Theheatenergyreleasedbyburningbutanewasknown,andthepercentageenergylossusingtheequipmentcouldbedeterminedandadjustedtogettheresultforthebiscuit.Theexperimentalset-upandtheresultsforPart1oftheexperimentareshownbelow.

digitaltemperature

probe

canister of butane

Part 1

recorderPart 1 – The heat content of butane1. Measuretheinitialmassofabutanecanister.2. Measurethemassofametalcan,add250mLofwater

andre-weigh.3. Setuptheapparatusasinthediagramandmeasurethe

initialtemperatureofthewater.4. Burnthebutanegasforfiveminutes.5. Immediatelymeasurethefinaltemperatureofthe

water.6. Measurethefinalmassofthebutanecanisterwhen

cool.

Results table for Part 1

Quantity Measurement

massofemptycan 52.14g

massofcan+waterbeforecombustion 303.37g

massofbutanecanisterbeforeheating 260.15g

massofbutanecanisterafterheating 259.79g

initialtemperatureofwater 22.1°C

finaltemperatureofwater 32.7°C


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a. i. Writethebalancedthermochemicalequationforthecompletecombustionofbutane. 2marks

ii. Calculatetheamountofheatenergyabsorbedbythewaterwhenitwasheatedbyburningthebutane.Giveyouranswerinkilojoules. 2marks

iii. Calculatetheexperimentalvalueofthemolarheatofcombustionofbutane.GiveyouranswerinkJmol–1. 2marks

iv. Usetheknownenthalpychangeforbutanetocalculatethepercentageenergylosstotheenvironmentusingthefollowingrelationship. 1mark

percentage energy loss = theoretical value of experimental v∆H − aalue of

theoretical value of ∆

∆H

H( )

×100

1


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Theexperimentalset-upandtheresultsforPart2oftheexperimentareshownbelow.

crucibleand

biscuit

Part 2

recorder

digitaltemperature

probe

Part 2 – The heat content of a Krispy Kracker1. Measurethemassofacrucible,addabiscuitand

re-weigh.2. Setuptheapparatusasinthediagram,usingthesame

canofwaterasusedinPart1,andmeasuretheinitialtemperatureofthewater.

3. Burnthebiscuituntiltheflamerunsout.4. Immediatelymeasurethefinaltemperatureofthe

water.5. Measurethefinalmassofthecruciblewhencool.

Results table for Part 2

Quantity Measurement

massofcrucible 44.33g

massofbiscuit+cruciblebeforecombustion 46.75g

massofcrucibleaftercombustion 44.34g

massofwater(fromPart1) 251.23g

initialtemperatureofwater 28.5°C

finaltemperatureofwater 34.9°C


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b. i. CalculatetheenergycontentofKrispyKrackersusingthedataintheresultstableforPart2.GiveyouranswerinkJ/100g. 2 marks

ii. ExplainwhytheenergycontentofabiscuitcannotbegiveninkJmol–1. 1mark

c. AssumethatthesamepercentageheatenergylossoccurredwhenburningtheKrispyKrackeraswhenthebutanewasburntinPart1.

CalculateamoreaccuratevalueoftheenergycontentofKrispyKrackersinkJ/100g. 2marks


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Question 11 (7marks)Astudentinvestigatedtheelectroplatingofametalwithnickel.Thefollowingisherreport.

Electroplating a brass key with nickel

AimToinvestigatewhetherFaraday’slawsapplytotheelectroplatingofabrasskeywithnickel

ProcedureStep1–Theapparatuswassetupasinthediagrambelow.Theelectrolytesolutionwassupplied.Thebrass

keywassanded,weighedandplacedinthesolution,asshownbelow.

Ni electrode

holder

brass key

solutioncontaining Ni2+

Step2–Thecurrentwasturnedonforexactly20minutes.Thecurrentandvoltageweremeasuredwhenthepowerwasturnedon.

Step3–Thekeywasremovedfromthesolution,patteddrywithapapertowelandweighed. Steps1–3wererepeatedfortwomorekeys.

ResultsThreetrialsoftheexperimentwereconducted,X,YandZ.

Trial Initial mass of brass key

(g)

Final mass of brass key

(g)

Mass of nickel deposit

(g)

Current (A)

Voltage (V)

X 2.774 2.907 0.133 0.52 2.4

Y 3.068 3.269 0.201 0.54 2.2

Z 3.122 3.310 0.188 0.50 1.9

Predicted mass for Trial X using Faraday’s laws

m(Ni) g=× ×

× =0 52 20 60

9650058 7

20 19. . .

ConclusionFaraday’slawsapplytotheelectroplatingofabrasskeywithnickel.


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Evaluatethestudent’sexperimentaldesignandreport.Inyourresponse:• identifyandexplainonestrengthoftheexperimentaldesign• suggesttwo improvementsormodificationsthatyouwouldmaketotheexperimentaldesignandjustifyyour

suggestions• commentonthevalidityoftheconclusionbasedontheresultsobtained.


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END OF QUESTION AND ANSWER BOOK

Instructions

• Aquestionandanswerbookisprovidedwiththisdatabook.

Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.

CHEMISTRYWritten examination

Tuesday 8 November 2016 Reading time: 9.00 am to 9.15 am (15 minutes) Writing time: 9.15 am to 11.45 am (2 hours 30 minutes)

DATA BOOK

©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2016

Victorian Certificate of Education 2016

2016CHEMISTRYDATABOOK 2

Table of contents Page

1. Periodictableoftheelements 3

2. Theelectrochemicalseries 4

3. Physicalconstants 5

4. SIprefixes,theirsymbolsandvalues 5

5. 1HNMRdata 5–6

6. 13CNMRdata 7

7. Infraredabsorptiondata 7

8. 2-aminoacids(α-aminoacids) 8–9

9. Formulasofsomefattyacids 10

10. Structuralformulasofsomeimportantbiomolecules 10

11. Acid-baseindicators 11

12. Acidityconstants,Ka,ofsomeweakacidsat25°C 11

13. Valuesofmolarenthalpyofcombustionofsomecommonfuelsat298Kand101.3kPa 11

3 2016CHEMISTRYDATABOOK

TURN OVER

1. P

erio

dic t

able

of t

he el

emen

ts

1 H

1.0

hydrogen

2 He

4.0

helium

3 Li

6.9

lithium

4 Be

9.0

beryllium

5 B

10.8

boron

6 C

12.0

carbon

7 N

14.0

nitrogen

8 O

16.0

oxygen

9 F 19.0

fluorine

10

Ne

20.2

neon

11

Na

23.0

sodium

12

Mg

24.3

magnesium

13

Al

27.0

alum

inium

14

Si

28.1

silicon

15

P 31.0

phosphorus

16

S 32.1

sulfur

17

Cl

35.5

chlorine

18

Ar

39.9

argon

19

K

39.1

potassium

20

Ca

40.1

calcium

21

Sc

45.0

scandium

22

Ti

47.9

titanium

23

V

50.9

vanadium

24

Cr

52.0

chromium

25

Mn

54.9

manganese

26

Fe

55.8

iron

27

Co

58.9

cobalt

28

Ni

58.7

nickel

29

Cu

63.5

copper

30

Zn

65.4

zinc

31

Ga

69.7

gallium

32

Ge

72.6

germanium

33

As

74.9

arsenic

34

Se

79.0

selenium

35

Br

79.9

brom

ine

36

Kr

83.8

krypton

37

Rb

85.5

rubidium

38

Sr

87.6

strontium

39

Y

88.9

yttrium

40

Zr

91.2

zirconium

41

Nb

92.9

niobium

42

Mo

96.0

molybdenum

43

Tc

(98)

technetium

44

Ru

101.1

ruthenium

45

Rh

102.9

rhodium

46

Pd

106.4

palladium

47

Ag

107.9

silver

48

Cd

112.4

cadm

ium

49

In

114.8

indium

50

Sn

118.7

tin

51

Sb

121.8

antim

ony

52

Te

127.6

tellurium

53

I 126.9

iodine

54

Xe

131.3

xenon

55

Cs

132.9

caesium

56

Ba

137.3

barium

57–7

1 lanthanoids

72

Hf

178.5

hafnium

73

Ta

180.9

tantalum

74

W

183.8

tungsten

75

Re

186.2

rhenium

76

Os

190.2

osmium

77

Ir

192.2

iridium

78

Pt

195.1

platinum

79

Au

197.0

gold

80

Hg

200.6

mercury

81

Tl

204.4

thallium

82

Pb

207.2

lead

83

Bi

209.0

bism

uth

84

Po

(210)

polonium

85

At

(210)

astatine

86

Rn

(222)

radon

87

Fr

(223)

francium

88

Ra

(226)

radium

89–1

03

actinoids

104

Rf

(261)

rutherfordium

105

Db

(262)

dubnium

106

Sg

(266)

seaborgium

107

Bh

(264)

bohrium

108

Hs

(267)

hassium

109

Mt

(268)

meitnerium

110

Ds

(271)

darmstadtium

111

Rg

(272)

roentgenium

112

Cn

(285)

copernicium

114

Fl

(289)

flerovium

116

Lv

(292)

livermorium

57

La

138.9

lanthanum

58

Ce

140.1

cerium

59

Pr

140.9

praseodymium

60

Nd

144.2

neodym

ium

61

Pm

(145)

prom

ethium

62

Sm

150.4

samarium

63

Eu

152.0

europium

64

Gd

157.3

gadolinium

65

Tb

158.9

terbium

66

Dy

162.5

dysprosium

67

Ho

164.9

holmium

68

Er

167.3

erbium

69

Tm

168.9

thulium

70

Yb

173.1

ytterbium

71

Lu

175.0

lutetium

89

Ac

(227)

actinium

90

Th

232.0

thorium

91

Pa

231.0

protactinium

92

U

238.0

uranium

93

Np

(237)

neptunium

94

Pu

(244)

plutonium

95

Am

(243)

americium

96

Cm

(247)

curium

97

Bk

(247)

berkelium

98

Cf

(251)

californium

99

Es

(252)

einsteinium

100

Fm

(257)

fermium

101

Md

(258)

mendelevium

102

No

(259)

nobelium

103

Lr

(262)

lawrencium

Thevalueinbracketsindicatesthemassn

umberofthelongest-livedisotope.

79

Au

197.0

gold

atom

icnum

ber

relativeatom

icmass

symbolofelement

nameofelement


2. The electrochemical series

Reaction Standard electrode potential (E0) in volts at 25 °C

F2(g)+2e–⇌ 2F–(aq) +2.87

H2O2(aq)+2H+(aq)+2e–⇌ 2H2O(l) +1.77

Au+(aq)+e–⇌ Au(s) +1.68

Cl2(g)+2e–⇌ 2Cl–(aq) +1.36

O2(g)+4H+(aq)+4e–⇌ 2H2O(1) +1.23

Br2(l)+2e–⇌ 2Br–(aq) +1.09

Ag+(aq)+e–⇌ Ag(s) +0.80

Fe3+(aq)+e–⇌ Fe2+(aq) +0.77

O2(g)+2H+(aq)+2e–⇌ H2O2(aq) +0.68

I2(s)+2e–⇌ 2I–(aq) +0.54

O2(g)+2H2O(l)+4e–⇌ 4OH–(aq) +0.40

Cu2+(aq)+2e–⇌ Cu(s) +0.34

Sn4+(aq)+2e–⇌ Sn2+(aq) +0.15

S(s)+2H+(aq)+2e–⇌ H2S(g) +0.14

2H+(aq)+2e–⇌ H2(g) 0.00

Pb2+(aq)+2e–⇌ Pb(s) –0.13

Sn2+(aq)+2e–⇌ Sn(s) –0.14

Ni2+(aq)+2e–⇌ Ni(s) –0.23

Co2+(aq)+2e–⇌ Co(s) –0.28

Fe2+(aq)+2e–⇌ Fe(s) –0.44

Zn2+(aq)+2e–⇌ Zn(s) –0.76

2H2O(l)+2e–⇌ H2(g)+2OH–(aq) –0.83

Mn2+(aq)+2e–⇌ Mn(s) –1.03

Al3+(aq)+3e–⇌ Al(s) –1.67

Mg2+(aq)+2e–⇌ Mg(s) –2.34

Na+(aq)+e–⇌ Na(s) –2.71

Ca2+(aq)+2e–⇌ Ca(s) –2.87

K+(aq)+e–⇌ K(s) –2.93

Li+(aq)+e–⇌ Li(s) –3.02


TURN OVER

3. Physical constants

Avogadro’sconstant(NA) 6.02×1023mol–1

chargeononeelectron –1.60×10–19C

Faradayconstant(F) 96500Cmol–1

gasconstant(R) 8.31JK–1mol–1

ionicproduct(self-ionisationconstant)forwater(Kw)at298K 1.00×10–14mol2L–2

molarvolume(Vm)ofanidealgasat273K,101.3kPa(STP) 22.4Lmol–1

molarvolume(Vm)ofanidealgasat298K,101.3kPa(SLC) 24.5Lmol–1

specificheatcapacity(c)ofwater 4.18Jg–1K–1

density(d)ofwaterat25°C 1.00gmL–1

1atm 101.3kPa=760mmHg

0°C 273K

4. SI prefixes, their symbols and values

SI prefix Symbol Value

giga G 109

mega M 106

kilo k 103

deci d 10–1

centi c 10–2

milli m 10–3

micro μ 10–6

nano n 10–9

pico p 10–12

5. 1H NMR dataTypicalprotonshiftvaluesrelativetoTMS=0Thesecandifferslightlyindifferentsolvents.Wheremorethanoneprotonenvironmentisshownintheformula,theshiftreferstotheonesinboldletters.

Type of proton Chemical shift (ppm)

R–CH3 0.8–1.0

R–CH2–R 1.2–1.4

RCH=CH–CH3 1.6–1.9

R3–CH 1.4–1.7


Type of proton Chemical shift (ppm)

or CH3

ORC

OCH3

NHR

CO

2.0

CH3R

C

O

2.1–2.7

R–CH2–X(X=F,Cl,BrorI) 3.0–4.5

R–CH2–OH,R2–CH–OH 3.3–4.5

R

NHCH2R

CO

3.2

R—O—CH3 or R—O—CH2R 3.3

O C

O

CH32.3

R

OCH2R

CO

4.1

R–O–H 1–6(variesconsiderablyunderdifferentconditions)

R–NH2 1–5

RHC CH2 4.6–6.0

OH 7.0

H 7.3

R

NHCH2R

CO

8.1

R

H

CO

9–10

R

OC

H

O9–13


TURN OVER

6. 13C NMR data

Type of carbon Chemical shift (ppm)

R–CH3 8–25

R–CH2–R 20–45

R3–CH 40–60

R4–C 36–45

R–CH2–X 15–80

R3C–NH2 35–70

R–CH2–OH 50–90

RC CR 75–95

R2C=CR2 110–150

RCOOH 160–185

7. Infrared absorption dataCharacteristicrangeforinfraredabsorption

Bond Wave number (cm–1)

C–Cl 700–800

C–C 750–1100

C–O 1000–1300

C=C 1610–1680

C=O 1670–1750

O–H(acids) 2500–3300

C–H 2850–3300

O–H(alcohols) 3200–3550

N–H(primaryamines) 3350–3500


8. 2-amino acids (α-amino acids)

Name Symbol Structure

alanine Ala

H2N CH COOH

CH3

arginine Arg

H2N CH COOH

CH2 CH2 CH2 NH

NH

C NH2

asparagine Asn

H2N CH COOH

CH2

O

C NH2

asparticacid Asp

H2N CH COOH

CH2 COOH

cysteine Cys

H2N CH COOH

CH2 SH

glutamine Gln

H2N CH COOH

CH2 CH2

O

C NH2

glutamicacid Glu

H2N CH COOH

CH2 CH2 COOH

glycine Gly H2N CH2 COOH

histidine His

H2N CH COOH

CH2 NH

N

isoleucine Ile

H2N CH COOH

CH3 CH CH2 CH3


TURN OVER

Name Symbol Structure

leucine Leu

H2N CH COOH

CH2

CH3 CH CH3

lysine Lys

H2N CH COOH

CH2 CH2 CH2 CH2 NH2

methionine Met

H2N CH COOH

CH2 CH2 S CH3

phenylalanine Phe

H2N CH

CH2

COOH

proline ProHN

COOH

serine Ser

H2N CH COOH

CH2 OH

threonine Thr

H2N CH COOH

CH3 CH OH

tryptophan Trp

H2N CH

CH2

COOH

HN

tyrosine Tyr OH

H2N CH

CH2

COOH

valine Val

H2N CH COOH

CH3 CH CH3


9. Formulas of some fatty acids

Name Formula

lauric C11H23COOH

myristic C13H27COOH

palmitic C15H31COOH

palmitoleic C15H29COOH

stearic C17H35COOH

oleic C17H33COOH

linoleic C17H31COOH

linolenic C17H29COOH

arachidic C19H39COOH

arachidonic C19H31COOH

10. Structural formulas of some important biomolecules

OH

OH

OH

OH HO

O O

O

H H

H

H H

H

H H

CH2OH

CH2OH

HOCH2

sucrose

OH

HO

O

H H H H

H

HOCH2

deoxyribose phosphate

O

O

P OO

C

C

C

H

H

OH

OH

OH

H

H

H

glycerol

adenine guanine cytosine thymine

NH2 NH2

CC

CCH

CH

C

CCHC

HN HN

H2N

N N

N

C C

CO

C N N

O

C

C

O

ONH

CH

CH3CH

CHNH

NHN

HN


END OF DATA BOOK

11. Acid-base indicators

Name pH range Colour change Ka

Acid Basethymolblue 1.2–2.8 red yellow 2×10–2

methylorange 3.1–4.4 red yellow 2×10–4

bromophenolblue 3.0–4.6 yellow blue 6×10–5

methylred 4.2–6.3 red yellow 8×10–6

bromothymolblue 6.0–7.6 yellow blue 1×10–7

phenolred 6.8–8.4 yellow red 1×10–8

phenolphthalein 8.3–10.0 colourless red 5×10–10

12. Acidity constants, Ka, of some weak acids at 25 °C

Name Formula Ka

ammoniumion NH4+ 5.6×10–10

benzoic C6H5COOH 6.4×10–5

boric H3BO3 5.8×10–10

ethanoic CH3COOH 1.7×10–5

hydrocyanic HCN 6.3×10–10

hydrofluoric HF 7.6×10–4

hypobromous HOBr 2.4×10–9

hypochlorous HOCl 2.9×10–8

lactic HC3H5O3 1.4×10–4

methanoic HCOOH 1.8×10–4

nitrous HNO2 7.2×10–4

propanoic C2H5COOH 1.3×10–5

13. Values of molar enthalpy of combustion of some common fuels at 298 K and 101.3 kPa

Substance Formula State ΔHc(kJ mol–1)hydrogen H2 g –286carbon(graphite) C s –394methane CH4 g –889ethane C2H6 g –1557propane C3H8 g –2217butane C4H10 g –2874pentane C5H12 1 –3509hexane C6H14 1 –4158octane C8H18 1 –5464ethene C2H4 g –1409methanol CH3OH 1 –725ethanol C2H5OH 1 –13641-propanol CH3CH2CH2OH 1 –20162-propanol CH3CHOHCH3 1 –2003glucose C6H12O6 s –2816

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