SS-氯化物-硬度

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1、悬浮物、氯化物、硬度时间安排预习时，首先洗净SS测定需用的称量瓶，将滤膜置入，烘第一遍；再清洗其他玻璃器皿。预习，绘制数据表格，考虑注意事项。上课前，采集“若谷”学区前的湖水样品，每人装满1个矿泉水瓶，上课时带来。上午上课时，先集中听讲解“称量”，然后分成小组称滤膜，或准备滴定。集中听讲解3个实验。分头做实验。2011年不用事前已经把膜烘过了2.4.DeterminationofSuspendedSolidsPurpose:Tounderstandtheprinciplesofweighingmethod,andoneofthesamplepretreatmentmethods,f

2、iltration,aswellastomasterthemethodsofmeasurementofsuspendedsolid.QuestionsWhatisSS?Definition:remainedon0.45µmmembraneWhatisweighingmethod?WeightdifferenceHowtoholdtheweighingbottle?Donotdirecttouchit.Whatissamplepretreatment?Separationmethods:Filtrationultra-filtrationExtractionCentrifugatio

3、nOsmosisChromatographyElectrophoresisKeypointsTogettheconstantweightEnoughdrytimeEnoughcoolingtimeDesiccatorDesiccant---Sigel2.5.DeterminationofChloridePurpose:Tounderstandtheprincipleofchloridemeasurement,andtomasteroneofthevolumetricmethods,precipitationtitration.Whatistitration?Oneofthevolu

4、metricmethods,reactionoftitrantandtargetanalyte.Typeoftitration:Acid-baseRedox(reducing-oxidizing)ComplexationprecipitationProcedureoftitrationFillingtitrantsolution,adjustingzeromark.PutXXmLsamplesolutionintoaflaskAddafewdropsofindicatorsolutionTitratewithtitrantsolutionuntiltheendpointRecord

5、thevolumeoftitrantconsumedcalculationprecipitationtitrationAg++Cl-AgClwhite,pKsp=9.742Ag++CrO42-Ag2CrO4reddish,pKsp=11.92Ag2CrO4ppt(moresoluble)formafterAgCl(lesssoluble)SuitablepHrange:6.5～10.51blankand2samplesforeachstudentNote:Vblank≒VsampleColorturning:lightyellowgreentoreddishsamplesDilut

6、edseawatersamplesTapwaterTitratetheblankfirst,forcomparingthecolor.2.6.DeterminationofTotalHardnessPurpose:Tounderstandtheprincipleofhardnessmeasurement,andtomasteroneofthevolumetricmethods,complexationtitration.Whatishardness?TotalhardnessisthetotalconcentrationofCaandMginwater,whichincludesc

7、arbonatehardnessandnon-carbonatehardness.Whatistemporaryhardness?CarbonatehardnessisequaltotheamountofCaandMgcarbonateorbicarbonateCa(HCO3)2CaCO3＋CO2＋H2OMg(HCO3)2MgCO3＋CO2＋H2OWhatishardness?Whatispermanenthardness?non-carbonatehardnessc