大连理工大学2008年一月分析化学(英强)C

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姓名：学号：院系：级班大连理工大学姓名：学号：院系：级班课程名称：分析化学（英强）试卷：C闭卷授课院(系)：化工学院考试日期：2008年1月8日试卷共6页装装订线一二三四五六七八九十总分标准分103010428/////100得分Ⅰ.Judgments(10points)1.Precisionindicatestheclosenessofthereplicatemeasurementinaset.()2.TheweakacidsH3BO3(pKa=9.24)andCH3COOH(pKa=4.75)canbetitratedwithstandardalkalinesolutiondirectly.()3.ThepHtransitionrangeofanacid-baseindicatorshouldbedependentonitspKHIn,andfallsinthetitrationcurvespartiallyorcompletely.()4.Incomplexometrictitration,aneffectivemethodfortitratingthemetalionsstep-by-stepistomasktheinterferingions.()5.Inpotentiometry,theliquidjunctionpotentialisdevelopedowingtothedifferencesinsizessoftheionsattheinterface.()6.Themaximummolarabsorptivityemaxisapropertyofasubstance.Thesensitivityofthedeterminationwillbelowforalargeemaxvalue.()7.Ingaschromatography,alargepartitioncoefficientKofacomponentindicatesthattheconcentrationofthecomponentinthemobilephaseislarge,andthentheretentiontimeislong.()8.InInfraredabsorptionspectroscopy(IR),theprerequisitefordeterminationofafunctionalgroup–C=CHisthatthefundamentallineofthefunctionalgroupindifferentcompoundsappearsatcertainrange.()9.In1HNMRmethod,wechoosethecompound(CH3)4Si(TMS)astheinternalstandard(itsd=0)becausetheshieldingparameterfortheprotonsinthiscompoundissmallerthanformostotherprotons.()10.InAASanalysis,oneoftheperquisitesforquantitativeanalysisisthatthenumbersofatomsingroundstatesapproximatethenumbersofthetotalatoms.()Ⅱ.Choice(30points)1.Forthefollowingdata,whichcontainstwosignificantfigures?()(A)[H+]=0.012mol×L-1(B)pH=6.37(C)m=0.3000g (D)wt=2.Forthefollowingstatements,()iswrong.(A)thelargertheKa,thelargerthetitrationbreak.thehighertheconcentrationofthetitrant,thelargerthetitrationbreak.thelargertheKs,thelargerthetitrationbreak.(D)thelargertheKsp,thelargerthetitrationbreak.3.ForthefollowingsetsofdatawhichcontainsthevalueshouldberejectedaccordingtoQtest(Q0.90=0.76,n=4),()0.1122，0.1126，0.1130，0.1134(B)87.50，88.50，89.00，89.50(C)4.03，4.04，4.05，4.130.2042，0.2044，0.2045，0.20474.ForthefollowingstatementsconcerningαY(H),whichiswrong?()(A)αY(H)decreasesaspHincreases.(B)αY(H)isalwayslessthan1.(C)lgαY(H)approacheszeroathighpH.(D)αY(H)increasesaspHdecreases.5.TheconcentrationsoftheacidsHCl,HAc(pKa=4.75)andHCOOH(pKa=3.75)areequal.WhentheyaretitratedwithNaOHstandardsolution,theorderofthetitrationbreaksis()（A）HClHCOOHHAc(B)HAcHCOOHHCl(C)HCOOHHAcHCl(D)HClHAcHCOOH6.IntheVolhardtitration,()Cl-istitratedwithAgNO3standardsolution,K2CrO4isusedasindicatorandthepHrangeis6.5-10.5.Cl-istitratedwithAgNO3standardsolution,K2Cr2O7isusedasindicatorandthemediumisacidic.Ag+istitratedwithNH4SCNstandardsolution,K2CrO4isusedasindicatorandthepHrangeis6.5-10.5.Ag+istitratedwithNH4SCNstandardsolution,ferricalumisusedasindicatorandthemediumisacidic.7.Inpotentiometry,thereferenceelectrodeshouldmeetthat()itspotentialisindependentoftemperatureitspotentialshouldbeequaltozeroitspotentialshouldbeconstantduringthedeterminationthereisnoliquidjunctionpotential8.InUV-Visspectrophotometry,thereasonsfortheapparentdeviationsfromBeer’sLaware().nonmonochromaticradiationandthereadingerrors, nonmonochromaticradiationandsystematicerrors,nonmonochromaticradiationandhighconcentrationofthesample, operationmistakesandrandomerrors.9.Inspectrophotometry,thesuitableabsorbancerangeis().(A)0~0.2 (B)0.3~1.0(C)0.2~0.7 (D)1.0~2.010.InAASanalysis,thewidthofanatomicabsorptionlineismainlydeterminedby()(A)thenaturalwidth(B)theDopplerbroadening(C)thepressurebroadening(D)StarkandZeemanbroadening11.ThefunctionoftheatomizationsysteminAASis()toemitcharacteristicradiationtoprovidetheenergytoobtainatomsthatingroundstatestoproducetheenoughstrongradiationtoemitelectrons12.Ingaschromatography,ifthebaselinewidthofapeakdecreasesonetimes,thecolumnefficiencywillbe()timesastheformer.(A)2(B)4(C)1/2(D)1/413.For1HNMRspectrum,whichofthechemicalshiftforthefollowingmarkedproton(s)inthecompoundsisthelargest.()(A)RCH2CH2OH；(B)RCH2CH2OH；(C)RCHO；(D)C6H6.14.InIRspectrum,theorderfortheabsorptionpeaksofthefunctionalgroup–C=Ointhecompounds(1)FCOF,(2)CH3COF,(3)CH3COClshouldbe().(A)(1)>(2)>(3)(B)(2)>(1)>(3)(C)(2)>(3)>(1)(D)(1)>(3)>(2)15.TheDopplerbroadeningoftheatomicabsorptionlineisfrom().(A)thermalmovementofatoms(B)collisionsbetweenunlikeatoms(C)collisionsbetweenlikeatoms(D)theuncertaintyeffectⅢ.Fillintheblanks.(10points)1.TheUV-Visspectrophotometerisusuallycomposedof,,samplecontainer,detector,signalprocessorsandreadouts.2.ThePBEfor(NH4)2C2O4is3.ThemetalionsMandNcanformcomplexesMRandNRwithcolor-formingreagentR.Atcertainwavelength,thetotalabsorbanceforMRandNRis0.530,andthetransmittanceforMRis40%.TheabsorbanceforNRisatthiswavelength.4.InGCanalysis,theTCDisproportionaltotheofthesubstancedetected,whiletheFIDworksproportionallyto.5.In1HNMR,thepeakarearatioforCH3CH2CHOfromdownfieldtoupfieldis.6.AFe3+solutionof10-3.10mol/ListitratedwithEDTAstandardsolution.TheminimumpHvalueforeffectivetitrationis,andatthispH,lgKFeY-’=.lgKFeY-=25.1lgY(H)14151617pH1.91.61.31.0Ⅳ.Calculations(42points,310pointsforproblems1,2,and3,12pointsforproblems4)1.A0.2150gsteelsampleisdissolvedinHClsolution.SnCl2reducestheFe3+ofthissolutiontoFe2+,andthenFe2+istitratedwith0.01726mol/LK2Cr2O7standardsolution,requiring22.32mL.Calculate,,thepercentageofironinthesteelsampleintermsof%Feand%Fe2O3.(=159.7gmol-1,MFe=55.85gmol-1)2.WeighingasamplecontainingCa0.0500g，dissovledandpreparedtobeasolutionof100.00mL，thenthevoltageofthesolutionismeasuredwithacellmadeupofaCa2+selectiveelectrodeandareferenceelectrodeat25℃,thevoltagereadingis385.0mV;Aftertheadditionof1.00mL0.100mol·L-1Ca2+standardsolutionandgoodmixing,measureagain,thevoltagereadingis4013.At500nm,acompoundAhasanabsorptivity100L·g-1·cm-1.A0.4500gsamplecontainingthecompoundAisdissolvedandthenpreparedina250mLvolumetricflask.Pipeta1.00mLaliquotandthendiluteto50.00mL.Thefinalsolutionhasanabsorbanceof0.37whenmea