VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D...

42
SAMPLE CHEMISTRY Written examination Day Date Reading time: *.** to *.** (15 minutes) Writing time: *.** to *.** (2 hours 30 minutes) QUESTION AND ANSWER BOOK Structure of book Section Number of questions Number of questions to be answered Number of marks A 30 30 30 B 10 10 90 Total 120 Students are permitted to bring into the examination room: pens, pencils, highlighters, erasers, sharpeners, rulers and one scientific calculator. Students are NOT permitted to bring into the examination room: blank sheets of paper and/or correction fluid/tape. Materials supplied Question and answer book of 41 pages Data book Answer sheet for multiple-choice questions Instructions Write your student number in the space provided above on this page. Check that your name and student number as printed on your answer sheet for multiple-choice questions are correct, and sign your name in the space provided to verify this. Unless otherwise indicated, the diagrams in this book are not drawn to scale. All written responses must be in English. At the end of the examination Place the answer sheet for multiple-choice questions inside the front cover of this book. You may keep the data book. Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room. © VICTORIAN CURRICULUM AND ASSESSMENT AUTHORITY 2017 Version 2 – April 2017 SUPERVISOR TO ATTACH PROCESSING LABEL HERE Victorian Certificate of Education Year STUDENT NUMBER Letter

Transcript of VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D...

Page 1: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

S A M P L E

CHEMISTRYWritten examination

Day Date Reading time: *.** to *.** (15 minutes) Writing time: *.** to *.** (2 hours 30 minutes)

QUESTION AND ANSWER BOOK

Structure of bookSection Number of

questionsNumber of questions

to be answeredNumber of

marksA 30 30 30B 10 10 90

Total 120

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

• StudentsareNOTpermittedtobringintotheexaminationroom:blanksheetsofpaperand/orcorrectionfluid/tape.

Materials supplied• Questionandanswerbookof41pages• Databook• Answersheetformultiple-choicequestionsInstructions• 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.

©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2017

Version2–April2017

SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education Year

STUDENT NUMBER

Letter

Page 2: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 2 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

eaQuestion 1

MethaneisarenewableenergysourcewhenitisextractedfromA. naturalgas.B. coalseamgas.C. underthesedimentonoceanfloors.D. decomposingplantandanimalmaterial.

Question 2Whichstatementaboutpetrodieselandbiodieseliscorrect?A. Petrodieselemitssoot(smallcarbonparticles)whenburningisincomplete;biodieselispollutant-free.B. Petrodieselisproducedbydistillingcrudeoil;biodieselisproducedbyesterificationoffattyacids.C. Petrodieselconsistsoflong-chainhydrocarbons;biodieselcontainsbenzeneanditsderivatives.D. Petrodieselhasgreaterviscosityandhenceflowsmoreslowlyalongfuellinesthanbiodiesel.

Question 3Whichoneofthefollowingsubstancespresentinfoodprovidesthelowestamountofenergypergramforthehumanbody?A. tristearin(atriglyceride)B. alanine(anaminoacid)C. cellulose(apolysaccharide)D. fructose(amonosaccharide)

Question 4Asubstancethatcouldbeformedasaproductwhenapolysaccharideundergoesenzyme-catalysedhydrolysisisA. H2OB. CO2

C. C6H12O6

D. CH2OH.CHOH.CH2OH

SECTION A – Multiple-choice questions

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

Page 3: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 3 CHEMISTRY(SAMPLE)

SECTION A – continuedTURN OVER

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 5Insulinisaproteinthatcontrolsaperson’sbloodsugarlevel.Astudenttestedfourseparatesamplesofpureinsulinintheformofsolidcrystals.Inwhichoneofthefollowingtestswouldtheprimarystructureofaninsulinsamplemostlikelybedisrupted?A. Dissolvethecrystalsinhydrochloricacid,addtheenzymepepsin,thenheatthesolution.B. Dissolvethecrystalsinwater,thenblendthesolutionataveryhighspeed.C. Dissolvethecrystalsinsodiumhydroxidesolution,thenheatthesolution.D. Dissolvethecrystalsinwater,thencoolthesolutioninanicebath.

Question 6Agroupofstudentsperformedacid-basetitrationstodeterminethemassofaspirininsometablets.Themanufacturerguaranteedthatthetrueaspirincontentwasbetween300mgand303mgpertablet.Whichsetofresultsforthemassofaspirininthetabletstestedwouldbedescribedasofrelativelyhighprecisionandrelativelylowaccuracy?A. 278mg,280mg,279mg,281mgB. 301mg,299mg,302mg,300mgC. 295mg,301mg,306mg,299mgD. 282mg,312mg,289mg,306mg

Question 7Whenhydrochloricacid,HCl,isaddedtoaluminiumsulfide,Al2S3,thehighlytoxicgashydrogensulfide,H2S,isevolved.Theequationforthisreactionis

Al2S3(s)+6HCl(aq)→2A1C13(aq)+3H2S(g)

Ifexcesshydrochloricacidisaddedto0.200molofaluminiumsulfide,thenthevolumeofhydrogensulfideproducedatstandardlaboratoryconditions(SLC)willbeA. 1.63LB. 4.90LC. 7.35LD. 14.7L

Page 4: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 4 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Use the following information to answer Questions 8 and 9.GhimLiwishestoinvestigatetheeffectofpHontheactivityoftheenzymeprotease.

Question 8GhimLiperformshertestsinflasksthatareplacedinawaterbathtokeeptheflasksandtheircontentsataconstanttemperatureof37°C.Undertheseconditions,thetemperatureatwhichtheexperimentisconductedisreferredtoastheA. control.B. dependentvariable.C. controlledvariable.D. independentvariable.

Question 9Inonetest,GhimLiraisesthepHofasolutioncontainingthereactantsandtheenzymeto13.0Whichoneofthefollowingwilloccur?A. Therateofthereactionthattheenzymeiscatalysingwillincrease.B. Thehydrogenbondingholdingtheenzymeinitsshapewillnotbedisrupted.C. AnyNH3

+andCOOHgroupsontheenzymewillbechangedtoNH2andCOO–groups.D. Thenatureofthebondinginteractionsbetweentheenzymeandthesubstratewillremainthesame.

Page 5: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 5 CHEMISTRY(SAMPLE)

SECTION A – continuedTURN OVER

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 10Beta-caroteneisfoundnaturallyinorangeandyellowvegetables.Inhumans,itcanbeconvertedtovitaminA1, asshownintheflowchartbelow.

O

OH

beta-carotene

retinal

retinol(vitamin A1)

TheinformationintheflowchartindicatesthatA. allthreecompoundscanbedistinguishedbytheirinfra-redspectra.B. allthreecompoundsareclassifiedassaturatedhydrocarbons.C. allthreecompoundswouldbehighlysolubleinwater.D. retinalisaketone,whileretinolisanalcohol.

Page 6: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 6 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 11Themassspectrumofpropanoicacid,CH3CH2COOH,isshownbelow.

10 15 20 25 30 35 40 45m/z

50 55 60 65 70 75

100

80

60

40

relativeintensity

20

0

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

Thepeakatm/z74A. representstheparentioncontainingthecarbon-13isotope.B. representsthespecies[CH3CH2COOH]+.C. representsthespeciesCH3CH2COOH.D. iscommonlyknownasthebasepeak.

Question 12Considerthefollowingenergyprofileforaparticularchemicalreaction,whereI,IIandIIIrepresententhalpychangesduringthereaction.

I

II

IIIenthalpy(kJ mol–1) reactants

products

Whichoneofthefollowingstatementsiscorrect?A. Theactivationenergyforthereversereactionis(III–II).B. ThenetenergyreleasedfortheforwardreactionisrepresentedbyII.C. TheenergyrequiredtobreakthereactantbondsisrepresentedbyII.D. TheenergyreleasedbytheformationofnewbondsisrepresentedbyI.

Page 7: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 7 CHEMISTRY(SAMPLE)

SECTION A – continuedTURN OVER

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 13Theoxidationofsulfurdioxideisanexothermicreaction,asshownintheequationbelow.Thereactioniscatalysedbyvanadium(V)oxide.

2SO2(g)+O2(g)→2SO3(g)

Whichoneofthefollowingenergyprofilediagramscorrectlyrepresentsboththecatalysedandtheuncatalysedreactions?

enthalpy(kJ mol–1)

enthalpy(kJ mol–1)

enthalpy(kJ mol–1)

enthalpy(kJ mol–1)

A. B.

C. D.

catalysed reactionuncatalysed reaction

Key

Question 14Theequationforthefermentationofglucose,C6H12O6,inthepresenceofyeastisshownbelow.

C6H12O6(aq)yeast

2C2H5OH(aq)+2CO2(g)

Data

Reactant or product Concentration (g mol–1)

C6H12O6 180.0

C2H5OH 46.0

CO2 44.0

Whatisthepercentageatomeconomyfortheproductionofethanolbythisreaction?A. 25.6%B. 50.0%C. 51.1%D. 100%

Page 8: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 8 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Use the following information to answer Questions 15 and 16.Thenumberofmoleculespresentinasampleofoxygen,O2,gasincertainconditionshasadistributionofkineticenergiesshownbyCurve1inthegraphbelow.Afteronechangeismadetotheoriginalconditions,asecondcurveisdrawnonthesameaxes(Curve2).Theareasunderthetwocurvesarethesame.

Curve 1

Curve 2number of

O2 molecules

kinetic energy (J) Ea

Question 15WhatchangewasmadetotheoriginalconditionsshownbyCurve1,whichledtothedistributionshownbyCurve2?A. TheO2samplewasheated.B. MoreO2moleculeswereaddedtothecontainer.C. Apowderedcatalystwasblownintothecontainer.D. SomeO2moleculeswereremovedfromthecontainer.

Question 16Onthegraph,EarepresentstheactivationenergyforareactionbetweenO2andanothergas.Underitsfinalconditions,representedbyCurve2,thenumberofmoleculesofO2inthesamplethathavesufficientenergytoreactisrepresentedbytheA. areaunderCurve2totherightofEa.B. maximumheightofCurve2.C. totalareaunderCurve2.D. heightofCurve2atEa.

Page 9: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 9 CHEMISTRY(SAMPLE)

SECTION A – continuedTURN OVER

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 17Largedepositsofmethanehydratehavebeendiscovereddeepunderthesedimentontheoceanfloor.Ithasbeensuggestedthatmethanehydratedepositscouldbecommerciallyminedtoprovideacleanfueloncethetrappedmethaneisextracted.Methanehydratehasacomplexstructure.ThesimplifiedformulaformethanehydrateisCH4·6H2O.Theamountofenergyreleasedbythecompletecombustionofmethaneextractedfroma1.00kgsampleofCH4·6H2OatSLCisA. 8.89×102kJB. 7.17×103kJC. 4.30×104kJD. 5.56×104kJ

Question 18InrechargeablebatteriesA. theanodealwayshasanegativepolarity.B. whenthecelldischarges,itactsasagalvaniccell.C. whenthecellrecharges,electronsmustflowintothepositiveelectrode.D. theproductsofthehalf-cellreactionsmigratebackandforthbetweentheelectrodes.

Question 19

H HC

H

CH C C C H

H HH H

H

H

H

HHH

C

C HH

C

H

HH

C

WhatisthecorrectIUPACsystematicnameforthecompoundshownabove?A. 4,5-dimethylheptaneB. 3,4-dimethylheptaneC. 4-methyl-5-ethylhexaneD. 2-ethyl-3-methylhexane

Question 20CoenzymeQ10isasubstanceproducedbythehumanbody.Itisinvolvedintheprocessofcellularrespiration,whichistheprimarysourceofenergyinbodycells.InwhichoneofthefollowingprocessesiscoenzymeQ10mostlikelyinvolved?A. favouringtheforwardreactionofcellularrespirationB. actingasanantioxidanttoremoveelectronsfromthecellC. enablingthetransportofcarbondioxideawayfromthecellD. changingtheorientationofatomsattheactivesiteofthesubstrate

Page 10: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 10 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Use the following information to answer Questions 21–23.Potassiummetal,K,wasdiscoveredin1807inEnglandbySirHumphryDavy.Small,shinybeadsofmoltenpotassiumwereproducedwhenanelectriccurrentfromanearlybatterywaspassedthroughmoltenpotassiumhydroxide,KOH.Theelectrolyticcellisshowninthediagrambelow.

anode(graphite)

cathode(graphite)

globules ofmolten potassium

molten KOH

strong heat

Question 21Whatcurrentwasflowingthroughthecellif0.152gofmoltenpotassiumwasproducedinthefirstminute?A. 4.00×10–8 AB. 2.42×10–6 AC. 6.25AD. 375A

Question 22 IfinsteadDavyhadelectrolyseda1.0MKOHsolutionat25°C,stillusinggraphiteelectrodes,whatmainproductswouldbeobservedattheanodeandcathode,respectively?A. carbondioxidegas,hydrogengasB. oxygengas,moltenpotassiumC. carbondioxidegas,oxygengasD. oxygengas,hydrogengas

Question 23Today,somemetalsarestillextractedfromtheirmoltencompoundsusingelectrolyticcells.Aluminiumisextractedfromitsmoltenoxide,Al2O3,byelectrolysis.If0.60molofelectronsarepassedthroughmoltenAl2O3,whatamountofaluminiumwillbeproduced?A. 0.20molB. 0.30molC. 0.60molD. 0.90mol

Page 11: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 11 CHEMISTRY(SAMPLE)

SECTION A – continuedTURN OVER

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Use the following information to answer Questions 24 and 25.Titaniumisawidelyusedmetalthatisextractedfromitsore,titaniumdioxide,TiO2,intwostages.

Stage1 Theimpureoxideisconvertedtotitanium(IV)chloride,TiCl4,at1000°C. Theequationforthisreactionis

Reaction1 TiO2(s)+2Cl2(g)+2C(s)→TiCl4(g)+2CO(g)

TheTiCl4isthenpurifiedinanatmosphereofargongas.

Stage2 ThepureTiCl4vapourisreactedwithmoltenmagnesium,Mg,inanatmosphereofargongasat1000°C. Theequationforthisreactionis

Reaction2 TiCl4(g)+2Mg(l)→Ti(s)+2MgCl2(l)

Thisreactiontakesabouttwodays.Thetitaniummetalproducedisthenprocessedtopurifyit.

Question 24Whichstatementaboutthetworeactionsiscorrect?A. TheconjugateoxidisingagentofTiCl4inReaction2isTi.B. TheconjugatereducingagentofCinReaction1isCO.C. Boththecarbonandmagnesiumactasreducingagents.D. InReaction1,chlorinegasoxidisesTiO2toTiCl4.

Question 25Inthetworeactions,themostlikelyroleofargongasistoA. reducetheriskofanexplosionoccurringathightemperatures.B. drivethereactionsforwardtoincreasethepercentageyield.C. excludeoxygenandhencepreventTifromformingoxides.D. actasacatalysttolowerthecostofproduction.

Question 26Hydrogen,H2,isproducedonanindustrialscalefrommethane,CH4.Theequationforthereactionis

2H2O(g)+CH4(g)⇌CO2(g)+4H2(g)

Ifaninertgasisaddedtotheequilibriumsystemataconstanttemperatureandaconstantvolume,theconcentrationofH2willA. increase.B. decrease.C. notchange.D. decreasethenincrease.

Page 12: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 12 Version2–April2017

SECTION A – continued

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

Question 27Whichoneofthefollowingskeletalstructuresrepresentsaprimaryamide?

H

H

H

HN

N

O

O

O

HN

O

H

H

HH

H

HCN

N

H

HH

O

O

A. B.

C. D.

Question 28

NaOH(aq)

CH3CH2CH2CH2OH

HCl, solid AlCl3 catalyst NH3 (dissolved in ethanol)X Y Z

Whatarethesemi-structuralformulasofX,YandZforthereactionpathwayshownabove?

X Y Z

A. CH3CH2CH2CH3 CH3CH2CH2CH2Cl CH3CH2CH2CH2NH2

B. CH3CH2CHCH2 CH3CH2CHClCH3 CH3CH2CHNH2CH3

C. CH3CH2CH2CH3 CH3CH2CH2CHCl2 CH3CH2CH2CONH2

D. CH3CH2CHCH2 CH3CH2CH2CH2Cl CH3CH2CH2CH2NH2

Page 13: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 13 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

END OF SECTION ATURN OVER

Use the following information to answer Questions 29 and 30.Rubystandardisedacitricacid,C6H8O7,solutionagainstapreviouslystandardisedsodiumhydroxide,NaOH,solution.Theequationforthetitrationreactionwas

C6H8O7(aq)+3NaOH(aq)→Na3C6H5O7(aq)+3H2O(l)

Question 29Ruby’sresultsareshowninthetablebelow.

Quantity Measurement

volumeofNaOHsolution 20.00mL

molarityofNaOHsolution 0.125M

meantitreofC6H8O7solution 23.6mL

Whatwastheconcentrationofcitricacidinthesolution?A. 0.035MB. 0.049MC. 0.105MD. 0.316M

Question 30UnknowntoRuby,theNaOHsolutionsuppliedhadabsorbedsomecarbondioxide,CO2,fromtheair.CO2isweaklyacidicandreactswithNaOH.WhattypeoferrorwillthiscontaminationoftheNaOHleadtointhisanalysis,andwhatwillbeitslikelyeffectonthemeantitreofcitricacid?

Type of error Likely effect on the mean titre of citric acid

A. random greaterthanwouldbeifnocontaminationhadoccurred

B. random lowerthanwouldbeifnocontaminationhadoccurred

C. systematic greaterthanwouldbeifnocontaminationhadoccurred

D. systematic lowerthanwouldbeifnocontaminationhadoccurred

Page 14: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 14 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 1–continued

Question 1 (7marks)Whenmakingsaladsandwiches,Tomprefershomemademayonnaiseonhisbread,whileGitaprefersasoft,solidspreadthatismadefromhydrogenatedvegetableoil.Tommakeshismayonnaisewitholiveoil.Whenoliveoilismetabolised,onefattyacidthatisproducedislinoleicacid.Itsskeletalstructureisshownbelow.

O

OH

linoleic acid

Gita’sfavouritevegetableoilspreadismanufacturedfromcanolaoil.Whencanolaoilismetabolised,onefattyacidthatisproducediselaidicacid.Itsskeletalstructureisshownbelow.

O

OH

elaidic acid

a. Onbothoftheskeletalstructuresabove,circleallC=Cdoublebondsthatshowacisconfiguration. 1mark

b. Islinoleicacidclassifiedasanomega-3fattyacidorasanomega-6fattyacid?Justifyyouranswer. 2marks

SECTION B

Instructions for Section BAnswerallquestionsinthespacesprovided.Writeusingblueorblackpen.Givesimplifiedanswerstoallnumericalquestions,withanappropriatenumberofsignificantfigures;unsimplifiedanswerswillnotbegivenfullmarks.Showallworkinginyouranswerstonumericalquestions;nomarkswillbegivenforanincorrectanswerunlessitisaccompaniedbydetailsoftheworking.Ensurechemicalequationsarebalancedandthattheformulasforindividualsubstancesincludeanindicationofstate,forexample,H2(g),NaCl(s).Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.

Page 15: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 15 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

c. Chooseoneofthefattyacidsbelowbyticking()theboxbesideitandindicateifitissaturated,monounsaturatedorpolyunsaturated. 1mark

linoleicacid

elaidicacid

d. Consideratriglyceridethatcontainsthreelinoleicacidtailsandatriglyceridethathasthreeelaidicacidtails.

Predictwhichofthesetwotriglycerideswouldhavethehighermeltingpoint.Justifyyouranswer. 3marks

Page 16: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 16 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continued

Question 2 (5marks)Amylaseisanenzymethatcatalysesthehydrolysisofstarchandsugarsintoglucose.Therearetwomodelsthatexplainhowenzymeswork:thelock-and-keymodelandtheinducedfitmodel.

a. Applyyourunderstandingofthelock-and-keymodeltodrawandannotateasetofsimplediagramstoexplainhowamylasecatalysesthehydrolysisofadisaccharide. 3marks

b. Ifinsteadtheamylasecatalysesthehydrolysisofadisaccharideaccordingtotheinducedfitmodel,inwhatway(s)wouldtheinteractionbedifferent?Youmayuselabelleddiagramstoexplainyouranswer. 2marks

Page 17: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 17 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

Question 3 (6marks)Thefollowingtablelistsastudent’ssummarynotesaboutfoodchemistry.Itcontainssomecorrectandincorrectstatements.

Statementnumber

Statement

1 Themonomersofstarcharebondedbyglycosidiclinksandthemonomersofproteinsarebondedbypeptidelinks.

2 Thehydrolysisofaproteinrequiresthepresenceofbothanenzymeandacoenzyme.

3 Anenzymecanonlycatalyseaspecificbiochemicalreactiononce,sinceitisconsumedinthereaction.

4 Sucroseisadisaccharideformedbyacondensationreactionbetweenthemonomersglucoseandfructose.

5 Fatshavelowermeltingpointsthanoilsbuttheyarebothclassifiedastriglycerides.

6 Whenanoilishydrolysed,glycerolandthreefattyacidsareproduced.

7 Oxidativerancidityoccurswhenasaturatedtriglycerideisexposedtooxygen.Thiscausesthesaturatedtriglyceridetoformcompoundssuchasaldehydesandketones.

8 Antioxidantsarereducingagentsthatslowdowntherateofoxidativerancidity.

9 Thedenaturationofaproteinisthebreakingdownofitssecondaryandtertiarystructures.

10 Zwitterionsareionsthatareproducedwhenaproteinisbrokendownbyheat.

a. Identifytwocorrectstatementsbywritingthestatementnumbersintheboxesprovidedbelow. 2marks

Statementnumber Statementnumber

b. Identifytwoincorrectstatementsbywritingthestatementnumbersinthetableprovidedbelow. Explainwhyeachstatementisincorrect. 4marks

Statement number

Explanation

Page 18: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 18 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 4–continued

Question 4 (6marks)Claireisanalysingasampleofpainttodeterminetheorganicsolventsthatarepresent.Sheseparatesthedifferentcompoundsandanalyseseachoneusinginfra-red(IR)spectroscopy,and13Cand1HNMRspectroscopy.ClairefindsthatoneofthecompoundsthatsheisolateshasamolecularformulaofC5H10O.Theresultsforthiscompoundforeachtypeofspectroscopyusedareshowninthespectraonpages18–20.Usetheinformationprovidedtoanswerthequestionsonpage21.

wave number (cm–1)

IR spectrum100

50

0

transmittance(%)

4000 3000 2000 1500 1000 500

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

Page 19: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 19 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 4–continuedTURN OVER

200220 180 160 140 120 100 80ppm

60 40 20 0

13C NMR spectrum

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

Page 20: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 20 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 4–continued

9 8 7 6 5ppm

4 3 2 1 0

1H NMR spectrum

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

1H NMR data

Chemical shift Splitting pattern

1.0 3

2.4 4

Page 21: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 21 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

a. FromtheIRspectrumofthecompound,identifytheorganicfamilytowhichthiscompoundbelongs.Justifyyouranswerbyreferringtotherelevantwavenumber. 2marks

b. Drawastructuralformulaforthiscompoundthatisconsistentwiththedataprovided.Explainyourreasoningbyreferringtothisdata. 4marks

Page 22: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 22 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 5–continued

Question 5 (12marks)Ascorbicacid,alsocalledvitaminC,isanorganicacidthatplaysavitalroleinhumanhealth.ItsmolecularformulaisC6H8O6.CitrusfruitareacommonsourceofvitaminC.Inthefollowingexperiment,theconcentrationofvitaminCpresentinthejuicefromabatchoffreshlysqueezedlemonswasdeterminedbycarryingoutadirectredoxtitrationagainstthetri-iodideion.Thetri-iodideionisproducedwheniodinesolution,I2,andiodidesolution,I–,aremixedtogether.

I2(aq)+I–(aq)→ I3–(aq)

Theoverallredoxreactionoccurringis

C6H8O6(aq)+I3–(aq)→C6H6O6(aq)+2H+(aq)+3I–(aq)

a. Identifytheoxidisingagentinthistitrationreaction. 1mark

Page 23: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 23 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 5–continuedTURN OVER

Forthetitration,a20.00mLsampleofpurelemonjuicewasmadeupto250.00mLwithde-ionisedwaterina250mLvolumetricflask.Then,25.00mLaliquotsofthedilutedlemonjuiceweretransferredtoconicalflasksandtitratedagainstapreviouslystandardised2.000×10–4MI3–solution,whichwaslightbrownincolour.Todetectthe endpoint,starchwasaddedwhenthemixturebecameaverypalebrown.Thisstarchindicatorturnedfromdeepbluetocolourlessattheendpoint.Theaveragetitrewasfoundtobe15.65mL.

b. i. Calculatetheamount,inmoles,ofI3–presentintheaveragetitre. 1mark

ii. Calculatetheamount,inmoles,ofC6H8O6presentineach25.00mLaliquotofdilutedlemonjuice. 1mark

iii. CalculatethemolarityofC6H8O6intheoriginalsampleofpurelemonjuice.Hence,statetheconcentrationofvitaminCinthelemonjuice. 3marks

Page 24: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 24 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continued

c. TheskeletalstructuresofvitaminCandvitaminD3areshownbelow.

O O

OO

O

O

H

H

H

H

vitamin C

OH

vitamin D3

i. Aswithmostorganiccompoundsmetabolisedbythehumanbody,vitaminsexistaspairsofopticalisomers.OnlytheopticalisomerofvitaminC,whichisshownintheskeletalstructureabove,occursnaturally.

OntheskeletalstructureofvitaminC,circlethetwochiralcarbons. 2marks

ii. Inhumans,theenzymeknownasL-ascorbateoxidasecanbreakdownonlythenaturallyoccurringopticalisomerofvitaminC.

Explainwhythisenzymewouldnotbreakdowntheotheropticalisomer. 2marks

iii. Theanalysisofthelemonjuiceinpart b.waspossiblebecausevitaminCiswater-soluble.

Intermsofitsstructure,explainwhyvitaminCiswater-solublewhilevitaminD3isnot. 2marks

Page 25: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 25 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

CONTINUES OVER PAGE

Page 26: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 26 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 6–continued

Question 6 (6marks)Theglycaemicindex(GI)isavalueassignedtofoodsbasedonhowslowlyorquicklythecarbohydratesinfoodsarebrokendowntocauseanincreaseinbloodsugarlevels.TheGIofpureglucoseisassignedavalueof100.Foodsmaybeclassifiedashavingalow,mediumorhighGIaccordingtothevaluesgiveninthetablebelow.

Glycaemic index (GI) Value

low ≤55

medium 56–69

high ≥70

CarbohydrateswithlowGIvaluesaremoreslowlydigested,absorbedandmetabolised,andcausealowerandslowerriseinbloodglucoselevelsthancarbohydrateswithhigherGIvalues.In2016,aresearchteamatTuftsUniversityundertookastudytodeterminewhetherGIvaluesareaccurateandreproducible.Sixty-threevolunteerswererecruitedforthestudythatinvolvedsixtestingsessionsover12weeks.Eachsessioninvolvedthevolunteersrandomlybeinggivenafoodsampleofwhitebread (asimplecarbohydratethatwasusedasthetestfood)oraglucosedrink(usedasareferencecontrol).Eachfoodsamplecontained50gramsofavailablecarbohydrate.BloodglucoselevelsweremeasuredatmultiplepointsforfivehoursaftereatingandtheGIvaluewascalculatedusingstandardformulas.TheteamfoundthatthemeanGIvalueofwhitebreadforthestudypopulationwas62,placingitinthecategoryoffoodswithamediumGIvalue.However,deviationsaveraged15pointsineitherdirection,effectivelyplacingwhitebreadinallthreeGIcategories.TheteamfoundthatvariationsinGIvaluesdifferedacrossindividualsaswellaswithinthesameindividualbetweentrials,butbiologicalfactorssuchasgender,bodymassindexandphysicalactivityhadonlyaminoreffectonthevariabilityofGIvalues.

a. WhyisglucoseusedasthestandardfordeterminingGIvalues? 1mark

b. Whatismeantbytheterm‘availablecarbohydrate’? 1mark

Page 27: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 27 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

c. Glucoseisusedasthemainfuelbythebrainandnervoussystem,andisthepreferredsourceoffuelformostorgansandmusclesduringexercise.

SuggestwhyathletesmayprefertoincludefoodswithhighGIvaluesintheirdiet. 2marks

d. Withreferencetothefindingsofthestudy,commentonafoodlabelclaimthataproducthasalowGIvalue. 2marks

Page 28: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 28 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 7–continued

Question 7 (10marks)Acarmanufacturerisplanningtosellhybridcarspoweredbyatypeofhydrogenfuelcellconnectedtoanickelmetalhydride,NiMH,battery.Arepresentationofthehydrogenfuelcellisshownbelow.

NiMHbattery

H2(g) O2(g)

product outH2(g) → 2H+(aq) + 2e–

A

anode

B

cathodeswitch

polymerelectrolytemembrane

C

Theoverallcellreactionis

2H2(g)+O2(g)→2H2O(g)

a. i. Onthediagramabove,indicatethepolarityoftheanodeandthecathodeincirclesAandB,andidentifytheproductofthereactioninboxC. 2marks

ii. Writeanequationforthereactionthatoccursatthecathodewhentheswitchisclosed. 1mark

Cathodereaction

iii. Giveoneadvantageofusingahydrogenfuelcelltosupplyenergyratherthanusingpetrol, whichismadefromcrudeoil. 1mark

Page 29: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 29 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

b. ThestoragebatterytobeusedinthehybridcarscomprisesaseriesofNiMHcells.MHrepresents ametalhydridealloythatisusedasoneelectrode.Theotherelectrodecontainsnickeloxidehydroxide,NiOOH.TheelectrolyteisaqueousKOH.

electric carmotor

+

KOH(aq)

direction of electron flow

Thesimplifiedequationforthereactionattheanodewhilerechargingis

Ni(OH)2(s)+OH–(aq)→NiOOH(s)+H2O(l)+e–

Thesimplifiedequationforthereactionatthecathodewhilerechargingis

M(s)+H2O(l)+e– →MH(s)+OH–(aq)

i. Whatistheoverallequationforthedischargingreaction? 1mark

ii. Intheboxesonthediagramabove,indicatewhichistheMHelectrodeandwhichistheNiOOHelectrode. 1mark

iii. Intheboldboxprovidedabovethecelldiagram,useanarrow,→or←,toindicatethedirectionoftheelectronflowasthecellisdischarging. 1mark

iv. Thebatterydischargedfor60minutes,producingacurrentof1.15A.

Whatmass,ingrams,ofNiOOH,wouldbeusedduringthisperiod? 3marks

Page 30: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 30 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 8–continued

Question 8 (10marks)Carbonmonoxide,CO,reactswithammonia,NH3,toproducehighlytoxichydrogencyanide,HCN,aswellascarbondioxide,CO2,andhydrogen,H2.Thisreactionisendothermicandtheequationforthisreactionisshownbelow.

2CO(g)+NH3(g)⇌HCN(g)+CO2(g)+H2(g)

a. i. Writetheexpressionfortheequilibriumconstantforthisreaction. 1mark

ii. Inoneexperiment,amixtureofCOandNH3,togetherwithasuitablecatalyst,wasinjectedintoasealed100mLgassyringeandallowedtocometoequilibrium.

Whentheequilibriummixturewasanalysedataparticulartemperature,thefollowingconcentrationsweredetermined.

[CO]=0.0025M [NH3]=0.00125M [HCN]=0.0042M

Calculatetheequilibriumconstantforthereactionatthistemperature. 2marks

b. AnalyststheninvestigatedtheeffectoftwodifferentchangesontheequilibriumsystembymonitoringtheamountofHCN(inmoles)presentinthegasmixtureoveraperiodoftime.

i. Tick()theappropriateboxinthetablebelowtoshowtheexpectedeffectontheamountofHCN (inmoles)presentinthegasmixtureasaresultofeachchange. 2marks

Change investigated Expected effect on the amount of HCN

Increase Decrease No effect

Halvethevolumeofthegasmixture,keepingthetemperatureconstant.

Returnthevolumeofthegasmixtureto 100mL,theninjectsomepowderedpalladiumintothegassyringe.(PalladiumabsorbsH2gasontoitssurface.)

Page 31: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 31 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 8–continuedTURN OVER

ii. Completetheconcentration–timegraphontheaxesprovidedbelow,toshowwhatwillhappento theconcentrationsofHCNandNH3inanequilibriummixturewhenthevolumeofthegas mixtureissuddenlyhalvedataconstanttemperature. 2marks

Concentration–time graph for the equilibrium system

0

0.001

0.002

0.003

0.004

0.005

0.006concentration

(mol L–1)

0.007

0.008

0.009

0.010

time (s)

KeyHCNNH3

volume halvedat this point

Page 32: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 32 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continued

c. COgasisproducedwhenahydrocarbonfuel,suchasbutane,C4H10,isburntinalimitedairsupply.

WritethebalancedequationforthecombustionofC4H10inalimitedairsupply,assumingthatCOistheonlycarbon-basedoxidationproduct. 1mark

d. COpoisoningisonedangerfacedbyrescuersenteringaburningbuilding,soitisessentialthatrescuerswearappropriatebreathingapparatus.

HaemoglobininredbloodcellstakesupO2fromtheairinanequilibriumreactionrepresentedbyEquation1.

Equation1 Hb4(aq) + 4O2(aq) ⇌ Hb4O8(aq) K1

haemoglobin haemoglobin-oxygen complex

COmoleculescanalsoattachtohaemoglobinmolecules.TheequilibriumreactioninvolvedisrepresentedbyEquation2.

Equation2 Hb4(aq) + 4CO(aq) ⇌ Hb4(CO)4(aq) K2

haemoglobin haemoglobin-carbonmonoxide complex

IftheconcentrationofCOintheairinsideaburningbuildingincreasesto800ppm,anyonewhoisexposedtothiswillquicklyloseconsciousness,evenifoxygenispresent.Torevivethem,theymustbegivenpureoxygen.

WhatconclusionscanbemadeabouttherelativevaluesofequilibriumconstantsK1andK2? 2marks

Page 33: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 33 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

CONTINUES OVER PAGE

Page 34: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 34 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 9–continued

Question 9 (14marks)Agroupofstudentswassetthetaskofinvestigatingthemolarheatofcombustionofglucoseusingprimaryandsecondarydatathatwasobtainedfromtwodifferentexperimentaltechniques.Thefirstexperimentaltechniqueusedtofindthemolarheatofcombustionofglucoseinvolvedcollectingprimarydata.Thestudentssetuptheapparatusasshownbelow.Theyweighedoutasampleofpureglucosepowderintothecrucible,readyforthecombustion.Theyalsoweighedout150.0gofwaterintothecoppercalorimeterpotandmeasuredtheinitialtemperatureofthewater.

Experimental technique 1

stirrer

copper calorimeter pot

water

crucible

pipeclay triangle

tripodglucosepowder

thermometer

clamp

retortstand

heat-proof mat

Beforeburningtheglucosetodetermineanexperimentalvalueofitsheatcontent,thestudentsdecidedtocalculatethepredictedmaximumtemperatureriseofthewater.ThesetofdatatheyusedisshowninTable1.

Table 1. Data for determining the predicted maximum temperature rise of the water

Quantity Measurement

massofglucosepowder 2.002g

massofwater 150.0g

specificheatcapacityofwater 4.182Jg–1°C–1

initialtemperatureofwater 21.3°C

publishedmolarheatofcombustionofglucose 2805kJmol–1

molarmassofglucose 180.0gmol–1

Page 35: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 35 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 9–continuedTURN OVER

a. i. UsethedatafromTable1tocalculatethepredictedmaximumtemperatureriseofthewater. 3marks

ii. Thestudentsthensafelyignitedtheglucosepowder.Whenthepowderstoppedburning,thestudentsrecordedtheactualtemperatureriseofthewater.Theydeterminedthatthefinaltemperatureofthewaterwas48.5°C.

Comparetheexperimentaltemperaturerisewiththevaluethatthestudentspredictedandhencecommentontheaccuracyofthevalueoftheheatofcombustionofglucosethatthestudentswouldhaveobtainedusingthisexperimentaltechnique. 2marks

Page 36: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 36 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 9–continued

Thesecondexperimentaltechniqueforfindingthemolarheatofcombustionofglucoseinvolvedusingatypicalcommercialbombcalorimeter.Theapparatussetupbythestudentsisshownbelow.

Experimental technique 2

thermometer

insulatedcontainer

sealed vessel glucose powder

stirrer

ignition wire

water

pure oxygen in excess

Thestudentswereabletoobtainthefollowingsecondarydatafromacommercialfoodanalysislaboratory.

Table 2. Electrical calibration of bomb calorimeter

Quantity Measurement

current 1.78A

potentialdifference 5.65V

timecurrentpassed 135s

temperatureriseofwater 1.150°C

Table 3. Combustion of glucose

Quantity Measurement

massofglucose 1.324g

temperatureriseofwater 17.32°C

Page 37: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 37 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – continuedTURN OVER

b. i. Showbycalculationthatthecalibrationfactorofthebombcalorimeterobtainedbythestudentsis1180J°C–1. 2marks

ii. Using1180J°C–1asthecalibrationfactorofthebombcalorimeter,calculatethemolarheatofcombustionofglucoseinJmol–1. 3marks

iii. Comparetheexperimentalvaluefrompart b.ii.withthepublishedvalueofthemolarheatofcombustionofglucosegiveninTable1. 1mark

c. i. IdentifyoneofthedesignfaultsofExperimentaltechnique1thatwouldhavecontributedtoitslessaccurateresults. 1mark

ii. ExplainhowthedesignfeaturesofExperimentaltechnique2overcamethedesignfaultidentifiedinpart c.i.toobtainmoreaccurateresults. 2marks

Page 38: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 38 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 10–continued

Question 10 (14marks)ForhisextendedVCEChemistryexperimentalinvestigationproject,Chrisdecidedtoinvestigatewhetherthereisarelationshipbetweentherateofthereactionbetweenmagnesium,Mg,andhydrochloricacid,HCl,andtheconcentrationoftheacid.ThefollowingisanextractfromthescientificposterthatChrisproduced.

Question under investigation:Istherearelationshipbetweentherateofthereactionbetweenmagnesium,Mg,anddifferentconcentrationsofhydrochloricacid,HCl?

Equation for the reaction: Mg(s)+2H+(aq)→Mg2+(aq)+H2(g)

Experimental design:FourdifferentconcentrationsofHClweretested.Therateofeachreactionwasinvestigatedbymeasuringthevolumeofhydrogen,H2,gasproducedat60-secondintervals.

Hypothesis: Thegreatertheconcentrationoftheacid,thefasterthereactionwillbe.Iexpectthisbecause,forareactiontooccur,H+ionsmustcollidewithMgatoms.Thegreatertheconcentrationoftheacid,themorefrequentlytheH+ionswillcollidewiththesurfaceoftheMgandsothegreatertheamountofH2gasthatwillbeproduced.

a. Inhishypothesis,doesChrisdemonstrateanunderstandingofthechemistrythatisrelevanttothisexperimentalinvestigation?Explainyourreasoning. 2marks

Inhisposter,Chrisoutlinedhowtheexperimentalinvestigationwasconducted.Anextractfromhismethodologyisshowninthetablebelow.

Methodology: First,thevariableswereidentified.ThedecisionsImadeareshowninTable1.

Table 1. The variables identified

Variable Classification Details

massofMg controlledvariable ThefirstpieceofMgribbonwasweighedandmeasured,thenthesamelengthofMgwasusedforeachconcentrationofHCltested.

concentrationofHCl dependentvariable 0.5M,1.0M,1.5Mand2.0MsolutionsofHClweretested.

volumeofHCl controlledvariable 50.0mLwasusedforeachtest,measuredusingagraduatedmeasuringcylinder.

Page 39: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 39 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 10–continuedTURN OVER

b. IsChris’sidentificationoftheconcentrationofHClasthedependentvariablecorrect?Giveareasonforyouranswer. 1mark

Chris’sposterincludedadiagramoftheexperimentalset-up,supportedbyshortnotes,asshownbelow.

The experimental set-up:

syringe for injecting HCl

H2 gas collectingin graduatedmeasuring cylinder

stopwatch tabletdeviceto recordresults

sealedreaction flask

magneticstirrer to keepreactantsevenly mixed

water troughbeehive shelf

piece of Mg

Notes:• TimingbegantheinstantIstartedinjectingtheacidfromthesyringeabovetheflaskontothepiece

ofMg.• Thestopwatchwasmountednexttothegraduatedmeasuringcylinder,andthevolumeandtime

wererecordedusingavideoapponatabletdeviceandreplayedinslowmotiontoallowtheresultstobeobtained.

• Theinjectionof20.0mLHClintothesealedreactionflaskimmediatelypushed20.0mLofairoutoftheflaskandintothemeasuringcylinder.IrecordedonlythenetvolumeofH2gasproduced.

c. Identify onefeatureofChris’sexperimentalset-upandnotesabovethatwasdesignedtoimprovetheaccuracyoftheresults.Explainhowthisfeaturecouldimproveaccuracy. 3marks

Page 40: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY(SAMPLE) 40 Version2–April2017

do

no

t w

rit

e i

n t

his

ar

ea

SECTION B – Question 10–continued

Chrisalsorecordedhisobservationsonhisposter.

Observations: Forthe2.0MHCl,initiallytherewasveryrapidbubblingintheflask.Thebubblingslowedovertime.AllMgappearedtohavedissolved.Theflaskbecameveryhot.Forthe1.5Mand1.0MHClsolutions,thebubblingwasnotasrapidasforthe2.0MHCl,andforthe0.5MHClitwasmuchslower.Thesolutionswerestillbubblingwhentimingstopped.Theflasksbecamehot,althoughnotashotastheflaskcontaining2.0MHCl.

d. CommentonChris’sobservations,includingthedifferencesintherateofbubblingandhowwelltheexperimenthadbeencontrolled. 3marks

Chrisreplayedhisvideoinslowmotion,recordedhisexperimentalresultsinhislogbookandproducedagraphforhisposter.Thegraphisshownbelow.

Results:Graph of volume of H2 gas produced against time

2.0 M

1.5 M

1.0 M

0.5 M

Key120

100

80

60

40

20

00 100 200 300

time (s)400 500 600

volumeof H2 gas

(mL)

Page 41: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

Version2–April2017 41 CHEMISTRY(SAMPLE)

do

no

t w

rit

e i

n t

his

ar

ea

e. WhatconclusionsmightChrishavestated,givenhisresultsforthequestionunderinvestigationandhishypothesis? 2marks

f. SuggestoneotherquestionChriscouldasktoextendthisexperimentalinvestigationandbrieflyoutlineanexperimentaldesignthatwouldenableChristoanswerthisquestion.Youmaypresentyouranswerasalistofmainstepsorasasimpleflowchart. 3marks

END OF QUESTION AND ANSWER BOOK

Page 42: VCE Chemistry – Sample examination...CHEMISTRY (SAMPLE) 2 Version 2 – April 2017 SECTION A ot D O N O T W R I T E I N T H I S C. A R E A D O N O T W R I T E I N T H I S A R E A

CHEMISTRY (SAMPLE – ANSWERS)

© VCAA 2017 – Version 2 – April 2017

Answers to multiple-choice questions

Question Answer Question Answer

1 D 16 A

2 B 17 B

3 C 18 B

4 C 19 B

5 A 20 D

6 A 21 C

7 D 22 D

8 C 23 A

9 C 24 C

10 A 25 C

11 B 26 C

12 B 27 B

13 B 28 D

14 C 29 A

15 A 30 D