配置标液-preparation-of-a-standard-solution-and-diluti

1Investigation1–PreparationofastandardsolutionanddilutionDate_____________Name_________Class_________Objective:Theprincipleobjectiveofthisinvestigationistoprepareastandard0.200moldm-3NaClsolutionanddiluteitto0.0200moldm-3.Introduction:ConcentrationisdefinedasamountofsoluteperunitvolumeofsolutionC=n/VTheunitofconcentrationismoldm-3.Sodiumchloride(NaCl)isaprimarystandardbecauseitmeetscertainrequirements.Itmustbeavailableinahighlypurestate.Itmustbestableinair.Itmustbeeasilysolubleinwater.Itshouldhaveahighmolarmass.Insolution,whenusedinvolumetricanalysis,itmustundergocompleteandrapidreaction.Youweighaccuratelyasampleofsodiumchlorideanduseittomakeasolutionofconcentrationto0.200moldm-3.Thenyouusethisstandardsolutiontodiluteto0.0400molL-1.MaterialsSodiumchloride(NaCl)(analyticallypure)100mLbeaker10mLvolumetricpipetteTwo100mLvolumetricflasksBulbElectricbalanceDistilledwaterStirringrodLabspoonLabelProcedure:PartA1.Chooseaclean100mLbeaker.Determinethemassoftheemptybeakerandrecordthevaluewiththecorrectnumberofsignificantfigures.2.Transferbetween1.17and1.20gofsodiumchlorideintothebeakerandweighittothenearest0.01g.3.Addabout30mLdistilledwatertothebeakertodissolvethesolid.Stirtodissolvethesolidcompletely.4.Transferthesolutionintoa100mLvolumetricflask.5.Rinsethestirringrodandthebeakermakingsurealltheliquidgoesintothevolumetricflask.6.Adddistilledwateruntiltheleveliswithinabout1cmofthemarkontheneckoftheflask.7.Usingthedroppingpipetteaddenoughwatertobringthebottomofthemeniscustothemark.8.Insertthestopperandshakethoroughlytentimestoensurecompletemixing.9.Labeltheflaskwiththecontentsandthedate.PartB21.Usedistilledwatertocleana10mLpipette.2.Rinsethepipettebyusingthestandardsolutiontwice.3.Transfer10mLstandardsolutiontoa100mLvolumetricflask.4.Adddistilledwateruntiltheleveliswithinabout1cmofthemarkontheneckoftheflask.5.Usingthedroppingpipetteaddenoughwatertobringthebottomofthemeniscustothemark.6.Insertthestopperandshakethoroughlytentimestoensurecompletemixing.7.Labeltheflaskwiththecontents,yournameandthedate.DateCollection&ProcessingPartAMolarmassofsodiumchloride(gmol-1)Massofsodiumchlorideused(g)Amountofsodiumchloride(mol)Massofbeaker(g)Volumeofsodiumchloridesolution(mL)Concentrationofsodiumchloridesolution(molL-1)PartBVolumeofstandardsodiumchloridesolutionused(mL)Volumeofdilutesodiumchloridesolution(mL)Concentrationofdilutesodiumchloridesolution(molL-1)Evaluation____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________