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CHEMISTRYWritten examination
Wednesday 7 June 2017 Reading time: 10.00 am to 10.15 am (15 minutes) Writing time: 10.15 am to 12.45 pm (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• Questionandanswerbookof37pages.• 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.
©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2017
SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education 2017
STUDENT NUMBER
Letter
2017CHEMISTRYEXAM(NHT) 2
SECTION A – continued
Question 1Thediagrambelowrepresentsaparticularacid-basetitration.
14
7pH
025
volume of titrant added (mL)
Whichoneofthefollowingstatementsaboutthistitrationiscorrect?A. Attheequivalencepoint,thepHofthesolutioniscloseto4.5B. AsolutionofastrongbasehasbeendeliveredbytheburetteC. PhenolphthaleinisasuitableindicatorforthisreactionD. Thetitrantisasolutionofaweakacid
Question 2Manganesecanexistinseveraloxidationstates.Inwhichcompoundismanganeseinitshighestoxidationstate?A. Mn2O3B. KMnO4C. MnCO3D. MnO(OH)
Question 3ThesystematicnameofCH3C(CH3)ClCH2CH3isA. 1-chloro-1,1-dimethylpropane.B. 3-chloro-3-methylbutane.C. 2-chloro-2-methylbutane.D. 3-chloropentane.
SECTION A – Multiple-choice questions
Instructions for Section AAnswerall questionsinpencilontheanswersheetprovidedformultiple-choicequestions.Choosetheresponsethatiscorrect orthatbest answers thequestion.Acorrectanswerscores1;anincorrectanswerscores0.Markswillnotbedeductedforincorrectanswers.Nomarkswillbegivenifmorethanoneansweriscompletedforanyquestion.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.
3 2017CHEMISTRYEXAM(NHT)
SECTION A – continuedTURN OVER
Question 4Sodiumhydroxide,NaOH,solutionscarefullypreparedfromanalytical-gradeNaOHpelletscannotbeusedasprimarystandardsinacid-basetitrations.ThisisbecauseA. theNaOHsolutionspreparedarecolourless.B. strongbasesarecausticandcancausechemicalburns.C. theNaOHpelletsaretoodifficulttoputintovolumetricflasks.D. theexactconcentrationoftheNaOHsolutionsmadefromthepelletsisunknown.
Question 5Apureproteinsampleismixedwithdiluteacidat25°C.Whichstructure(s)oftheproteinislikelytobedisrupted?A. primaryandsecondaryB. secondaryandtertiaryC. primaryandtertiaryD. tertiaryonly
Question 6Inthediagrambelow,GraphYrepresentstheenergyprofileforthereactionbetweentwogasesinasealedcontainer.Theexperimentwasrepeatedandonechangewasmadetothereactionconditions.GraphZrepresentstheenergyprofileunderthenewconditions.
reactants
productsenthalpy
Graph YGraph Z
Key
WhichoneofthefollowingpossiblechangestothereactionconditionswouldresultinthechangeintheenergyprofilefromGraphYtoGraphZ?A. Theinitialtemperatureofthegaseswashigher.B. Aninertgaswasaddedtothereactioncontainer.C. Thevolumeofthereactioncontainerwasdecreased.D. Acatalystwasaddedtothereactioncontainerwiththegases.
Question 7Whichoneofthefollowingstatementsiscorrectforanexothermicreaction?A. Theenthalpychangeispositive.B. Theactivationenergyisnegative.C. Heatenergyisabsorbedfromtheenvironment.D. Theenthalpyofthereactantsishigherthanthatoftheproducts.
2017CHEMISTRYEXAM(NHT) 4
SECTION A – continued
Question 8AnunidentifiedorganicsubstancewiththemolecularformulaC4H8O2isfoundtoreactwithabase.Massspectrometryshowstheparentmolecularionhasamass-to-chargeratio,m/z,of88.
100
80
60
40
relativeintensity
20
0 20 40m/z
60 80 1000
Source:NISTChemistryWebBook;NISTMassSpectrometryDataCenterCollection; ©2014USSecretaryofCommerceonbehalfoftheUSA
Whichoneofthefollowingspeciesisconsistentwithapeakonthemassspectrumatm/z=45?A. [COOH]+
B. [CH3CH2O]+
C. [CH3CH2OH]+
D. [CH3CH2CH2COOH]+
Question 9Todeterminetheconcentrationofapeptideinamixtureofpeptides,whichoneofthefollowinganalyticaltechniqueswouldbeused?A. high-performanceliquidchromatographyB. thinlayerchromatographyC. paperchromatographyD. gaschromatography
5 2017CHEMISTRYEXAM(NHT)
SECTION A – continuedTURN OVER
Use the following information to answer Questions 10–12.Ammoniacanbesynthesisedbyreactingnitrogen,N2,gaswithhydrogen,H2,gasaccordingtothefollowingequation.
N2(g)+3H2(g)⇌2NH3(g) ΔH=–92kJmol–1
Question 10Theexpressionfortheequilibriumconstantforthisreactionis
A. NH
H N3
2 23[ ][ ][ ]
B. 2
33
2 2
NHH N[ ]
[ ][ ]
C. NH
H N3
2
23
23
[ ][ ] [ ]
D. NH
H N3
2
23
2
[ ][ ] [ ]
Question 11Ifaninertgasisaddedtotheequilibriumsystemataconstanttemperatureandaconstantvolume,theconcentrationofH2inthemixturewillA. increase.B. decrease.C. notchange.D. decreasethenincrease.
Question 12TherateatwhichequilibriumisestablishedcanbeloweredbyincreasingtheA. temperatureofthereactionmixtureataconstantvolume.B. totalvolumeofthereactionvesselataconstanttemperature.C. concentrationofthereactantsataconstanttemperature.D. pressureinthereactionvesselataconstanttemperature.
Question 13Magnesium,Mg,metalreactswithoxygen,O2,accordingtothefollowingequation.
2Mg(s)+O2(g)→2MgO(s) ΔH=–1200kJmol–1 M(Mg)=24.3gmol–1
Forthisequation,1200kJrepresentstheA. activationenergyforthereaction.B. heatenergyreleasedwhen2gofMgreacts.C. heatenergyreleasedwhen48.6gofMgreacts.D. heatenergyreleasedwhen1molofMgreacts.
2017CHEMISTRYEXAM(NHT) 6
SECTION A – continued
Question 14100mLof0.4Mnitricacid,HNO3,isaddedto100mLof0.1Mbariumhydroxide,Ba(OH)2.ThepHoftheresultingsolutionisA. 0.3B. 0.7C. 0.8D. 1.0
Question 15Whichoneofthefollowingfactorsisleastlikelytoaffecttherateatwhichthecomponentsofagasmixtureflowthroughagaschromatographycolumn?A. thelengthofthecolumnB. thetemperatureofthecolumnC. therateofflowofthecarriergasD. themolecularmassesofthegasesinthegasmixture
Question 16
CH3CH2ClNaOH
CH3CH2OHReagent X
CH3COOHCH3CH2CH2OH
Product Z
Forthereactionpathwayshownabove,whichofthefollowingcorrectlyidentifiesReagentXandProductZ?
Reagent X Product Z
A. O2 ethylethanoate
B. H+/Cr2O72– ethylpropanoate
C. NaOH propylpropanoate
D. H+/MnO4– propylethanoate
7 2017CHEMISTRYEXAM(NHT)
SECTION A – continuedTURN OVER
Use the following information to answer Questions 17 and 18.ThegalvaniccellshownbelowissetupunderafumehoodbyaChemistrystudentatauniversity.Chlorinegas,Cl2,iscontinuallybubbledthroughthelefthalf-cell.
V
Pt electrode
salt bridgeCu electrode
1 M CuSO4 solution(blue, 25 °C)
Cl2(g)(1 atm, 25 °C)
1 M NaCl solution(clear, 25 °C)
Question 17WhenthecellbeginstooperateA. thecellvoltagewillstartat1.02V,thenslowlydrop.B. theCuelectrodewillhavepositivepolarityandactasthecathode.C. electronswillmoveoutofthePtelectrodeandalongthewiringtotheCuelectrode.D. electronswillmovethroughthesaltbridgetowardstheCuhalf-cellandcompletethecircuit.
Question 18WhatisthestudentmostlikelytoobserveintheCuhalf-cellsometimeaftertheswitchisturnedon?A. bubblesformingovertheelectrodeB. theCuelectrodelookingcorrodedC. thesolutionbecomingalighterblueincolourD. crystalsofCugrowingovertheelectrode
2017CHEMISTRYEXAM(NHT) 8
SECTION A – continued
Question 19Asamplecontainingamixtureoffourstraight-chainalcohols–butanol,ethanol,hexanolandpentanol–isanalysedbygaschromatography.
detectorresponse
1 2 3retention time (min)
4 5 6
Q
Onthechromatogram,thepeakatQwasmostlikelyproducedbyA. butanol.B. ethanol.C. hexanol.D. pentanol.
Question 20Someinformationgivenonthelabelsofabottleofdisinfectantisshownbelow.
500 mL
SmileyCleanPowerful disinfectant
Active ingredient
BENZALKONIUMCHLORIDE1.5%w/w
DIRECTIONS
FOR HOSPITAL STANDARD DISINFECTION
Use undiluted
FOR GENERAL HOUSEHOLD USE
Dilute 1 part disinfectant with 20 parts water
Data• benzalkoniumchloride:C17H30ClN• density(SmileyClean):1.0gmL–1
• molarmassofC17H30ClN:283.5gmol–1
Theconcentration,inmolL–1,ofbenzalkoniumchlorideinadilutedsolutionofSmileyCleandisinfectant,readyforgeneralhouseholduse,isA. 1.5×10–2
B. 5.3×10–2
C. 2.5×10–3
D. 2.6×10–3
9 2017CHEMISTRYEXAM(NHT)
SECTION A – continuedTURN OVER
Question 21Thegraphbelowrepresentsthetitrationof1.0Msodiumcarbonatesolution,Na2CO3,against1.0Mhydrochloricacid,HCl.Thetitrationhastwoequivalencepoints,StageIandStageII,correspondingtotheadditionofsuccessiveprotonstothebase.
14
7pH
0
CO32–(aq)
Stage ICO3
2–(aq) + H+(aq) → HCO3–(aq)
Stage IIHCO3
–(aq) + H+(aq) → H2CO3(aq)
volume of HCl (mL)
WhichoneofthefollowingindicatorsisthemostappropriatetousetodetecttheendpointforStageII?A. phenolphthaleinB. methylorangeC. thymolblueD. phenolred
2017CHEMISTRYEXAM(NHT) 10
SECTION A – continued
Question 22Asealedgassyringecontainsanequilibriummixtureofbrownnitrogendioxidegas,NO2,andcolourlessdinitrogentetroxidegas,N2O4.Thisisshowninthediagrambelow.
gas syringe
plungergas mixturerubber stopper
Theequationforthisequilibriumreactionis
N2O4(g)⇌2NO2(g) ΔH=+57.20kJmol–1
Theplungerissuddenlypushedinattimet1,thusdecreasingthetotalvolumeofthegasmixture.Thetemperatureofthegasmixtureiskeptconstant.Whichoneofthefollowingconcentration–timegraphsrepresentsthechangethatoccurs?
NO2
N2O4
concentration(mol L–1)
time(min)t1
NO2
N2O4
concentration(mol L–1)
time(min)t1
NO2
N2O4
concentration(mol L–1)
time(min)t1
NO2
N2O4
concentration(mol L–1)
time(min)t1
A. B.
C. D.
Question 23Theequationbelowrepresentsthecompletecombustionofmethanol.
2CH3OH(l)+3O2(g)→2CO2(g)+4H2O(g)
Theheatofcombustionofmethanol,inkJg–1,isclosesttoA. 1450B. 725C. 45.31D. 22.66
11 2017CHEMISTRYEXAM(NHT)
SECTION A – continuedTURN OVER
Question 24NarrowstripsofMetalXwereplacedinsolutionsoffourdifferentsaltsinseparatetesttubes.Thetablebelowshowstheobservationsmadeafter10minutes.
Solution Observations
copper(II)sulfate smallreddishcrystalsformedonMetalX;bluecolourofsolutionlightenedslightly
iron(III)chloride solutionturnedfromayellowishcolourtoagreenishcolour
nickel(II)sulfate smallgreyishcrystalsformedonMetalX;greencolourofsolutionlightenedslightly
aluminiumsulfate noapparentchange
MetalXismostlikelyA. silver.B. copper.C. iron.D. nickel.
Question 25Ananalystisgivenaflaskcontaininga20.0mLsolutionof0.52Mbariumchloride,BaCl2.Sheadds 25.0mLof0.75Msulfuricacid,H2SO4.Shecollectsanddriestheresultingbariumsulfateprecipitate,BaSO4.Themassofthedriedprecipitateis2.43g.WhatistheconcentrationofSO4
2–ions,inmolL–1,inthefiltrate?A. 0.19B. 0.23C. 0.33D. 0.42
Question 26Whenethanol,C2H5OH,reactswithalimitedamountofdichromicacid,H2Cr2O7,thereactionproduceschromium(III)ions,Cr3+,andethanal,C2H4O.Whatisthebalancedhalf-equationfortheoxidationreaction?A. 2Cr2O7
2–(aq)→4Cr3+(aq)+7O2(g)+16e–
B. C2H5OH(aq)→C2H4O(aq)+2H+(aq)+2e–
C. Cr2O72–(aq)+14H+(aq)+6e– →2Cr3+(aq)+7H2O(l)
D. 3C2H5OH(aq)+Cr2O72–(aq)+8H+(aq)→2Cr3+(aq)+3C2H4O(aq)+7H2O(l)
2017 CHEMISTRY EXAM (NHT) 12
SECTION A – continued
Question 27An electric current is passed through water to which a very small amount of sodium chloride, NaCl, has been added. The electrolytic cell is shown in the diagram below.
C electrode(graphite)
C electrode (graphite)
H2O(1)NaCl(aq)
The net cell reaction is
2H2O(l) → 2H2(g) + O2(g)
Which one of the following statements applies to this electrolytic cell as it operates?A. H2O will be the reactant at each electrode.B. The rate of bubbling will be the same at each electrode.C. H2 gas will be produced at the anode and O2 gas will be produced at the cathode.D. For each mole of electrons passed through the cell, 1 mol of H2 gas will be collected.
13 2017 CHEMISTRY EXAM (NHT)
SECTION A – continuedTURN OVER
Use the following information to answer Questions 28 and 29.As part of an investigation into silver plating, a group of students wants to coat a metal object with silver, Ag, by electrolysis. They set up a simple electrolytic cell using silver nitrate, AgNO3, solution, as shown in the diagram below.
power supply
Agelectrode
metalobjectto be plated
AgNO3 solution
Question 28Which one of the following statements is correct?A. During the electrolysis, the concentration of the AgNO3 solution will not change.B. During the electrolysis, each gram of Ag deposited will require 1 mol of electrons.C. During the electrolysis, water will be the reactant at the Ag electrode.D. During the electrolysis, the Ag electrode will have negative polarity.
Question 29A total of 0.75 g of Ag is required to plate the metal object.The electrolytic cell is first operated at 0.75 A for 10 minutes. The current is then changed to 1.00 A.For how much longer would the cell need to operate to complete the plating?A. 71 sB. 220 sC. 450 sD. 670 s
2017CHEMISTRYEXAM(NHT) 14
END OF SECTION A
Question 30Primarycells,secondarycellsandfuelcellscanallbeusedassourcesofenergy.Thefeaturesthatcanbeassociatedwithoneormoreofthethreetypesofcellsincludethefollowing:1. Thecellisrechargeable.2. Thecellrequiresacontinuoussupplyofreactants.3. Reductiontakesplaceatthecathodewhendischarging.4. Oxidationtakesplaceatthepositiveelectrodewhenrecharging.
Whichoftheabovefeaturesaredisplayedbysecondarycells?A. 1,2and3B. 2,3and4C. 1,3and4D. 1,2,3and4
15 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
SECTION B
Instructions for Section BAnswerallquestionsinthespacesprovided.Writeusingblueorblackpen.Toobtainfullmarksforyourresponses,youshould:• givesimplifiedanswers,withanappropriatenumberofsignificantfigures,toallnumericalquestions;
unsimplifiedanswerswillnotbegivenfullmarks• showallworkinginyouranswerstonumericalquestions;nomarkswillbegivenforanincorrect
answerunlessitisaccompaniedbydetailsoftheworking• makesurechemicalequationsarebalancedandthattheformulasforindividualsubstancesincludean
indicationofstate;forexample,H2(g),NaCl(s).Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.
2017CHEMISTRYEXAM(NHT) 16
SECTION B – Question 1–continued
Question 1 (7marks)a. CompoundCmaybesynthesisedaccordingtothefollowingpathway.
CC
Cl
CH3
H
H
CH3
H
Compound A
Compound B
Compound C
Structural formula:
Name:
Name:
Semi-structural formula:
HCl(g)/catalyst
NH3 (ethanol)
i. DrawthestructuralformulaofCompoundAintheboxprovided. 1mark
ii. WritethesystematicnameofCompoundBintheboxprovided. 1mark
iii. Insertthesemi-structuralformulaandsystematicnameofCompoundCintheboxprovided. 2marks
17 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
b. Butan-1-ol,C4H9OH,canreactwithacidifiedpermanganateions,MnO4–,toproducebutanoic
acid,C3H7COOH.
i. Writeabalancedredoxhalf-equationfortheproductionofC3H7COOHfromC4H9OH. 1mark
ii. C3H7COOHreactswithethanol,C2H5OH,inthepresenceofsulfuricacid,H2SO4.
Nametheproductformed. 1mark
iii. Drawthestructuralformulaoftheproductnamedinpart b.ii. 1mark
2017CHEMISTRYEXAM(NHT) 18
SECTION B – Question 2–continued
Question 2 (7marks)Glutathioneisatripeptidethatisfoundinthehumanbody.Itactsasanantioxidant,helpingtopreventdamagetocells.Thesequenceforthistripeptideisglu-cys-gly.
a. Drawastructurethatrepresentsthissequenceofaminoacids,clearlyshowingthelinkagesbetweentheaminoacids. 3marks
b. Glutamicacidcanbeisolatedfromasampleofglutathione.
Drawastructureofglutamicacidina1.0Msodiumhydroxidesolution. 2marks
19 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
c. Inhumanbodycells,glutathioneisoxidisedtoglutathionedisulfide.Thisreactionisreversedinthepresenceoftheenzymeglutathionereductase.Thisenzymeworksoptimallyatbodytemperature.
Explainwhyglutathionereductasewouldnotbeeffectiveathighertemperatures. 2marks
2017CHEMISTRYEXAM(NHT) 20
SECTION B – Question 3–continued
Question 3 (6marks)AcompoundhasthemolecularformulaC5H10O2.Itisanalysedbyinfrared(IR),
13CNMRand1HNMRspectroscopy.Theresultingspectraareshownbelow.
100
50transmittance
(%)
04000 3000 2000 1500
wave number (cm–1)1000 500
IR spectrum
Data:SDBSWeb,http://sdbs.db.aist.go.jp, NationalInstituteofAdvancedIndustrialScienceandTechnology
ppm200 180 160 140 120 100 80 60 40 20 0
13C NMR spectrum
Data:SDBSWeb,http://sdbs.db.aist.go.jp, NationalInstituteofAdvancedIndustrialScienceandTechnology
9 8 7 6 5ppm
4 3 2 1 0
1H NMR spectrum
Data:SDBSWeb,http://sdbs.db.aist.go.jp, NationalInstituteofAdvancedIndustrialScienceandTechnology
21 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
Informationforthesplittingpatternofthe1HNMRspectrumisshownbelow.
Chemical shift Relative peak area Splitting pattern
4.1 2 4peaks
2.3 2 4peaks
1.3 3 3peaks
1.1 3 3peaks
a. UsingtheIRspectrumprovided,identifyabondinamoleculeofC5H10O2andgiveitswavenumber. 1mark
b. Usingthe1HNMRspectrumprovided,statethenumberofhydrogenenvironmentsinamoleculeofC5H10O2. 1mark
c. WhatspecificinformationaboutthestructureofamoleculeofC5H10O2isprovidedbythesplittingpatterninthe1HNMRspectrum? 1mark
d. DrawastructureconsistentwiththedataprovidedforamoleculeofC5H10O2.Explainhowthestructureyouhavedrawnissupportedbyevidencefromthe13CNMRspectrum,whichcontainsfivepeaks. 3marks
2017CHEMISTRYEXAM(NHT) 22
SECTION B – Question 4–continued
Question 4 (6marks)TheBradfordproteinassayisaspectroscopicmethodofdeterminingtheconcentrationofproteinsinasolution.TheBradfordproteinassayusesacidifiedCoomassieBluedye(G-250),whichchangesfrombrowntobrilliantbluewhenitbindstoproteinsinasolution.Theintensityofthebluecolourofthedyeincreasesastheconcentrationofproteinsinthesolutionincreases.TheabsorptionspectrausedfortheBradfordproteinassayareshowninthegraphbelow.
400 450 500 550wavelength (nm)
600 650
465 nm 595 nm520 nm 650 nm0.8
0.7
0.6
0.5
0.4absorbance
0.3
0.2
0.1
0.0
Coomassie Blue dye
Coomassie Blue dye (bound to protein)
Key
a. NamethetypeofspectroscopyusedintheBradfordproteinassay. 1mark
b. Whatwavelengthwouldbemostappropriatetodeterminetheconcentrationofproteinsinasolution?Justifyyouranswer. 2marks
23 2017 CHEMISTRY EXAM (NHT)
SECTION B – continuedTURN OVER
c. The Bradford protein assay was used to determine the concentration of proteins in a liver cell extract. • Equalvolumesofstandardsolutionsofproteinswereprepared.Thesamevolumeofdye
was added to each one.• Thespectrometerwasadjustedtoreadzeroabsorbanceforthe0µg mL–1 standard.• Theabsorbanceofeachofthestandardsolutionswasmeasuredandthedatawasplottedon
a graph. Thegraphbelowshowsthecalibrationcurveforabsorbanceasafunctionoftheconcentration
of proteins.
0.90
0.80
0.70
0.60
0.50absorbance
0.40
0.30
0.20
0.10
0.00 1000 200 300 400concentration of proteins (µg mL–1)
500 600 700 800
Priortoitsabsorbancebeingmeasured,1.50mLofthelivercellextractwasmadeupto10.00mLwithabuffersolution.Usingthesameequipmentwiththesamesettings,theabsorbanceofthedilutedsampleofthelivercellextractwasmeasuredas0.28
i. What is the concentration of proteins in the diluted sample of the liver cell extract? 1 mark
ii. Calculatetheconcentration,inmgmL–1,ofproteinsintheundilutedsampleofthelivercell extract. 2 marks
2017CHEMISTRYEXAM(NHT) 24
SECTION B – Question 5–continued
Question 5 (8marks)Somestudentssetupa‘lemonbattery’experimentusingfreshlysandedstripsofcopper,Cu,andiron,Fe,astheelectrodes.Thestudentsclosedtheswitch,measuredthevoltageanddeterminedthedirectionoftheflowofelectronsintheexternalcircuit.Adiagramdepictingtheirexperimentandatableoftheirresultsareshownbelow.
V
strip of Cu(Cu electrode)
strip of Fe(Fe electrode)
lemon
globe
voltmeter
Results
voltage 0.35V
movementofelectrons fromFetoCu
a. LemonjuicecanbeconsideredasanaqueoussolutionofH+ions.
Writebalancedhalf-equationsforthereactionsattheelectrodesinthecopper-ironlemonbattery. 2marks
• Cuelectrode
• Feelectrode
b. Identifytheelectrodethatactsasthecathode. 1mark
c. i. Usingtheelectrochemicalseries,statethetheoreticalvoltageforthislemonbattery. 1mark
ii. Explainwhytheexperimentalvalueofthevoltageisdifferentfromthetheoreticalvoltage. 2marks
25 2017 CHEMISTRY EXAM (NHT)
SECTION B – continuedTURN OVER
d. The Cu electrode in the lemon battery is replaced with a freshly sanded strip of aluminium, Al.
Forthisaluminium-ironlemonbattery,statetheexpecteddirectionofelectronflow.Justifyyour answer. 2 marks
2017CHEMISTRYEXAM(NHT) 26
SECTION B – Question 6–continued
Question 6 (13marks)Ethanoicacid,CH3COOH,istheactiveingredientinwhitevinegar.AsampleofwhitevinegarisanalysedtoaccuratelydeterminetheconcentrationofCH3COOHusingthefollowingsteps:Step1–Dilutea10.00mLsampleofthewhitevinegarto100.00mLinavolumetricflask.Step2–Rinsetheburettewiththestandardisedsodiumhydroxidesolution,NaOH,thatis
provided.Step3–FilltheburettewiththestandardisedNaOHsolution.Step4–Pipette20.00mLofthedilutedwhitevinegarsolutionintoa250mLconicalflask.Step5–Addseveraldropsofphenolphthaleinindicatortotheconicalflask.Titratethediluted
whitevinegarsolutionagainstthestandardisedNaOHsolution.Step6–RepeatSteps3–5untilconcordantresultsareobtained.
Theequationforthisanalysisis
CH3COOH(aq) +NaOH(aq)→CH3COONa(aq) + H2O(l)
Data
aliquotofdilutedwhitevinegarsolution 20.00mL
meantitreofNaOHsolution 25.60mL
concentrationofstandardisedNaOHsolution 0.1123M
a. i. CalculatetheconcentrationofCH3COOHintheundilutedwhitevinegarsample. 3marks
ii. IftheburetteisrinsedwithwaterinsteadofthestandardisedNaOHsolution,whatwouldbetheeffect,ifany,ontheexperimentalvalueobtainedfortheconcentrationofCH3COOHinwhitevinegar?Justifyyouranswer. 2marks
27 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
b. CH3COOHisaweakacid.
i. WritetheequationfortheionisationofCH3COOHinwater. 1mark
ii. WritetheexpressionfortheacidityconstantforCH3COOH. 1mark
c. AnalternativemethodofdeterminingtheconcentrationofCH3COOHinwhitevinegaristomeasurethepHofthevinegar.
Inanotherexperiment,thepHoftheundilutedwhitevinegarsampleisfoundtobe2.29usingacalibrateddigitalpHprobe.
CalculatetheconcentrationofCH3COOHintheundilutedwhitevinegarsampleusingthepHvalueprovided. 2marks
d. SuggestanexplanationforanydifferenceintheresultsobtainedfortheconcentrationofCH3COOHfromthetwodifferentexperiments. 2marks
e. AsolutionofCH3COOHisdiluted.
Whateffect,ifany,wouldthishaveonthepercentageionisationofCH3COOH?Justifyyouranswer. 2marks
2017CHEMISTRYEXAM(NHT) 28
SECTION B – Question 7–continued
Question 7 (7marks)Moltencarbonatefuelcells(MCFCs)canbeusedasastationaryenergysource.Theyoperateattemperaturesbetween600°Cand700°C.TheelectrolyteinanMCFCistypicallyamoltenmixtureoflithium,sodiumorpotassiumcarbonates.AsimplifieddiagramofanMCFCisshownbelow.
molten electrolyteCO3
2–
direction of electron flow
polarity polarity
porouselectrodes
H2(g)
H2O(g)CO2(g)
O2(g)CO2(g)
unreactedO2(g), CO2(g)
AtoneelectrodeoftheMCFC,carbondioxide,CO2,gasreactswithoxygen,O2,gastoformcarbonateions.Attheotherelectrode,hydrogen,H2,gasreactswithmoltencarbonateionstoformsteamandCO2gas.
a. Onthediagramabove
i. labelthepolarityoftheelectrodesinthecirclesprovided 1mark
ii. showthedirectionofelectronflowintheexternalcircuitbydrawinganarrowintheboxabovethecell. 1mark
b. Onasmallscale,electricitycanbegeneratedinavarietyofways.
WhatisoneadvantageofproducingelectricityfromanMCFCratherthanfromapetrolgenerator? 1mark
29 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
c. i. Writeabalancedhalf-equationfortheproductionofcarbonateionsfromCO2andO2. 1mark
ii. CalculatethevolumeofO2gas,at665°Cand2.50atm,neededtoproduce11.50molofcarbonateions. 3marks
2017CHEMISTRYEXAM(NHT) 30
SECTION B – Question 8–continued
Question 8 (10marks)a. Writethebalancedthermochemicalequationforthecompletecombustionofmethane. 2marks
b. Completeandlabeltheincompletediagramprovidedbelowtoshowtheenergyprofileforthecombustionofmethane.LabeltheΔH,activationenergyEaandtheproducts. 3marks
0enthalpy reactants
c. Asampleofbiogascontains78.0%,bymass,ofmethane.Thisbiogasisburntasasourceofenergy.
Calculatethemaximumamountofenergy,inkilojoules,thatcouldbeproducedfromthecombustionofthemethanepresentin100kgofthisbiogas. 3marks
31 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
d. Identifyoneadvantageandonedisadvantageofusingbiogasasanenergysource. 2marks
Advantage
Disadvantage
2017CHEMISTRYEXAM(NHT) 32
SECTION B – Question 9–continued
Question 9 (13marks)Whencolourlesshydrogen,H2 ,gasandpurpleiodine,I2 ,gasaremixedathightemperatures,theyreacttoproducecolourlesshydrogeniodide,HI.Thisreactiondoesnotgotocompletionbutinsteadformsanequilibriummixture.Theequationforthereactionisshownbelow.
H2(g) + I2(g) ⇌ 2HI(g) ΔH=positive
colourless purple colourless
a. AchemistinjectsequalamountsofH2gasandI2gasintoaninsulated,evacuatedandsealed1.0Lcontainertowhichatemperatureprobeisattached.Bothgasesandthecontainerhadaninitialtemperatureof250°C.Thechemist’sobservationsoverthenexthourareshowninthetablebelow.
Observations
Time from moment of mixing (min)
Temperature (°C) Colour of gas mixture
0 250 darkpurple
15 239 purple
30 232 palepurple
45 232 palepurple(nofurtherchange)
60 232 palepurple(nofurtherchange)
Explainwhytheinitialdark-purplecolourofthegasmixturelightenstopalepurpleandthenremainsunchanged. 2marks
b. Identifyonechangethatcouldbemadetotheoriginalreaction’sconditionssothatequilibriumisreachedatafasterrate.Justifyyouranswer. 2marks
33 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
c. Thechemistperformsthreeteststoobservehowtheequilibriummixturerespondstochange.
Predicttheeffectofeachofthefollowingchangesonthecolourofthegasmixtureasitwasafter60minutes.Justifyyouranswers. 9marks
• Heatthegasmixturetoaconstant280°C.Assumethevolumeremainsconstant.
Circlethepredictedeffectonthecolourofthegasmixture.
darker lighter unchanged
Justification
• Restorethetemperatureofthegasmixtureto232°C.Increasethevolumeofthecontainerto1.5Lataconstanttemperatureof232°C.
Circlethepredictedeffectonthecolourofthegasmixture.
darker lighter unchanged
Justification
• Restorethevolumeofthecontainerto1.0L.InjectsomeHIintothecontainerataconstanttemperatureof232°C.
Circlethepredictedeffectonthecolourofthegasmixture.
darker lighter unchanged
Justification
2017CHEMISTRYEXAM(NHT) 34
SECTION B – Question 10–continued
Question 10 (7marks)Abombcalorimeteriscalibratedusinganelectricalheater.Thedataforthecalibrationisgivenin Table1.
Table 1
initialtemperatureofthewater 22.53°C
finaltemperatureofthewater 25.23°C
currentsupplied 4.50A
voltagesupplied 5.80V
time 300s
a. UsethedatainTable1tocalculatethecalibrationfactorforthebombcalorimeter.StateyouranswerinkJ°C–1. 2marks
b. Methyllaurate(methyldodecanoate),C13H26O2,isacomponentofsomebiodieselsandisaliquidatroomtemperature.ThepreviouslycalibratedbombcalorimeterisusedtodeterminethemolarenthalpyofC13H26O2.
AsampleofC13H26O2isinjectedintothebombcalorimeterandthenburntinexcessoxygen. ThedataforthisexperimentisgiveninTable2.
Table 2
initialtemperatureofthewater 23.83°C
finaltemperatureofthewater 35.15°C
massofC13H26O2 0.905g
molarmassofC13H26O2 214.0gmol–1
Calculatetheamountofenergyreleased,inkilojoules,whenthesampleofC13H26O2wasburnt. 1mark
35 2017CHEMISTRYEXAM(NHT)
SECTION B – continuedTURN OVER
c. CalculatethemolarenthalpyofcombustionofC13H26O2 usingthedatafromthisexperiment. 3marks
d. Hence,completethefollowingbalancedequationforthecombustionofC13H26O2inexcessoxygen. 1mark
2C13H26O2(l)+37O2(g)→26CO2(g) +26H2O(g) ΔH=
2017CHEMISTRYEXAM(NHT) 36
SECTION B – Question 11–continued
Question 11 (6marks)AChemistryclasswasaskedtodeterminethesodiumcontentofaparticularbrandofpotatochipsbygravimetricanalysis.Theclass’resultswouldthenbecomparedwiththesodiumcontentstatedonthelabelonthepacketofpotatochips,whichwas‘sodium644mg/100g’.ThefollowingisanextractfromthelogbookofaparticularpairofstudentsidentifiedasPairA.
Procedure1. Approximately10gofpotatochipswereweighedandthencrushedwithamortarandpestle.2. Theoilymixturewastransferredtoabeakerandapproximately30mLofwaterwasadded.3. Afterstirring,themixturewastransferredtoaseparatingfunnel.Themixturewasshakenfor
twominutesandallowedtosettle.4. Thewaterlayerwasdrained,thenfiltered.Theresiduewaswashed.5. AgNO3solutionwasaddedtothefiltrateuntilnomoreAgClprecipitatewasobservedtoform.6. TheAgClprecipitatewasfiltered,rinsedanddried.7. TheAgClprecipitatewasscrapedoffthefilterpaperandintoabottle,thenweighed.
EquationNaCl(aq)+AgNO3(aq)→AgCl(s)+NaNO3(aq)
Results
massofpotatochips 9.832g
massofdriedAgCl 0.417g
Calculationsn(AgCl)=0.417/143.4mol=0.00291molThusn(Na+)=0.00291molHencem(Na+)in9.832gofpotatochips=0.00291×23.0=0.0669gSom(NaCl)in100gofpotatochips=0.0669×100/9.832g=1.73gAndm(Na)=1.73/58.5×23.0g/100g=0.680g/100g
Theresultsfortheentireclasswererecordedasfollows.
Pair A B C D E F G
Mass Na(g/100 g) 0.680 0.704 0.221 0.731 0.979 0.649 0.712
37 2017CHEMISTRYEXAM(NHT)
Analyseandevaluatetheexperimentaldesignandtheclass’results.Inyourresponse,youshould:• commentononeassumptionthathasbeenmadeinconductingthisexperiment• suggestamodificationthatcouldbemadetotheexperimentaldesignandjustifyyouranswer• commentontheconclusionsthatmightbedrawnfromtheclass’results• comparetheresultsobtainedwiththemanufacturer’sclaimandsuggestareasonforanydifference.
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
Wednesday 7 June 2017 Reading time: 10.00 am to 10.15 am (15 minutes) Writing time: 10.15 am to 12.45 pm (2 hours 30 minutes)
DATA BOOK
©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2017
Victorian Certificate of Education 2017
2017CHEMISTRYDATABOOK 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 2017CHEMISTRYDATABOOK
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
2017CHEMISTRYDATABOOK 4
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
5 2017CHEMISTRYDATABOOK
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
2017CHEMISTRYDATABOOK 6
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
7 2017CHEMISTRYDATABOOK
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
2017CHEMISTRYDATABOOK 8
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
9 2017CHEMISTRYDATABOOK
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
2017CHEMISTRYDATABOOK 10
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
11 2017CHEMISTRYDATABOOK
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 –20172-propanol CH3CHOHCH3 1 –2003glucose C6H12O6 s –2816