溶解氧2015

溶解氧DO时间安排预习时，洗净DO实验所需的玻璃器皿，倒扣晾干。每人1个溶解氧瓶。星期四上午在图书馆北面湖边的木栈道处，采集湖水样品，每人1瓶。回到实验室，集中听讲解。分头做实验。注意这是考试实验！2.7.DeterminationofDissolvedOxygenPurpose:Tounderstandtheprincipleofdeterminationofdissolvedoxygen,Tomasteroneofthevolumetricmethods,redoxtitration,aswellasthesamplecollectionandstoragefortheanalysisofdissolvedoxygen.QuestionsWhatisDO?WhatarethefactorsaffectingtheconcentrationofDO?Salinity,temperature,airpressure,algae…Whatcarefulness/attentionshouldbetakenwhensamplingDOsample?Anycontactwithairoragitationshouldbeavoided,andnoairbobblesareallowed.RedoxtitrationMn(II)Mn(OH)4dis.Mn(IV)MnO(OH)2(MnO2.2H2O)Mn2++I2S2O32-I-+S4O62-O2H+I-Indicator:starchsolutionI2+starchblueI-+starchcolorlessAdditionalquestionsDescribethecompoundformationandcolorchangeduringthetitration.Howdoesthecolorchange?Whyshouldthepotassiumiodidesolution(oneofthefixingsolutions)bebasic?碘化钾是碱的？Onesample,parallel(two)titrationsforeachstudent.SamplehandlingAttention!!BeCAREFULLwithH2SO4