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时间:2019-03-04
《chem 3024 - southern nazarene university:化工3024 -南拿撒勒大学》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、Chem3024NotesonpHTitrationLabFall2004Page7Theory-ThetheoryforthisexperimentisChapter10ofyourtextbook.TheexperimentalprocedureisExperiments23-7fromthepublisher’swebsite.1{Acopyoftheexperimentalprocedureispartofthisdocument,pages3-4.}YouwillusetheVernie
2、rLoggerPro™apparatustoacquireandprocessthetitrationdata.Thefollowingarechangesandclarificationstotheabovecitedexperimentalprocedure.Replacetheplasticburetabovewithyourglassburet.Adjusttheflowto~1dropper2seconds.Theapproximatevolumeofadropis1/20mL,butt
3、aketheinitialandfinalburetreadingssoyoucancheckthiscalibration.Procedure1.YoudonotneedtostandardizethepHprobesforthisexperiment.2.DONOTdrythissamplebecauseitmaydecomposebyheating.Instead,storeitinyourdesiccatorinaweighingbottlewithitscapremovedtoatlea
4、st24hours.Yourunknownsampleiseitherapuresolidweakacidoraweakbase;thefirststepwillbetodecidewhichyoursampleis.Thisisaccomplishedbypreparingthesamplefortheroughtitrationasdescribedinstep3byweighingapproximately0.7g,(accuratelyweighedto±0.1mg.)ofyoursamp
5、leintoa400-mLbeakeranddissolvinginapproximately200mLofdeionizedwater.UsethepHprobetomeasuretheinitialpHofthesolution.(BesurethatthelevelofthesolutioncomesabovetheceramicplugofChem3024NotesonpHTitrationLabFall2004Page7thepHelectrode;ifnecessaryadddeion
6、izedwatertothesolutionofyoursample.)IfthepH<7,yoursampleisaweakacid;ifthepH>7,aweakbase.Ifyoursampleisaweakacid,yourwilltitratewith0.1000MNaOH(±0.0005M);ifaweakbase,thetitrantwillbe0.1000MHCl(±0.0005M).Thesesolutionsarepresentinthelabascommerciallypre
7、paredandstandardizedtitrantsolution.1.Carryouttheroughtitrationasdescribedinstep3oftheattachedprocedure,usingthesamplepreparedinstep2above.Thecomputerwillrecordthetitrationdata.Onthefirsttitration,besuretocontinueuntilthepHis~12sothatifyoursampleispol
8、yproticyoucanseebothequivalencepoints.2.Basedonthevolumeoftitrantrequiredfortheroughtitrationinstep3,adjustyoursamplesizeforsubsequenttitrations,steps4and5ofthetextbookprocedure,soastocompletethetitrationwellpasttheendpointwithatotalvolumeofbe
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