當(dang)要(yao)求(qiu)得(de)到(dao)最(zui)高(gao)準(zhun)確(que)度(du)時(shi),應(ying)盡(jin)可(ke)能(neng)按(an)校(xiao)準(zhun)時(shi)的(de)條(tiao)件(jian)來(lai)操(cao)作(zuo),並(bing)要(yao)求(qiu)用(yong)分(fen)度(du)誤(wu)差(cha)的(de)校(xiao)準(zhun)值(zhi)。使(shi)用(yong)前(qian)量(liang)器(qi)應(ying)清(qing)洗(xi)幹(gan)淨(jing),如(ru)果(guo)校(xiao)準(zhun)時(shi)發(fa)現(xian)示(shi)值(zhi)容(rong)量(liang)有(you)偏(pian)差(cha)時(shi),應(ying)做(zuo)適(shi)當(dang)修(xiu)正(zheng)。
容量瓶
容量瓶
吸量管yongzhengliushuiqingxizhihou,zaiyongdaiyongyetichongxi。xiliangguanxiquyetizhilingbiaoxianyishanghuosuoxukeduxianyishangjihaomi。jianyishiyongnengshidaiceyetiziyouliudongdexiju,ruxiqiudeng。
weilededaozhengquedeliangchurongliang,xiliangguanyinganqichanpinbiaozhunzhongyouguanrongliangdingyisuoshudefangfacaozuo。xiliangguanyujieshourongqituolizhiqian,yingzunshouguidingdedengdaishijian。tongchangxiliangguanguabiyetiliuzhiliuyekoudedengdaishijianguiding3syizugoule,erqiebuxuyaozhunqueceding。yidanquedingwanyemiandadaoliuyekoubingquyujingzhi,xiliangguanjikeyujieshourongqituolijiechu。liuzailiuyekoudeyuyebudepaichu,er“吹出”式吸量管則應吹出其最後餘液作為量出容量的一部分。與滴定管一樣,非常粘稠的液體不能方便和準確地吸取。通常用於容量分析的稀釋水溶液是適用的,而且無明顯誤差。
量筒經清洗和幹燥後,充以待測液體至標稱容量刻線或所需的刻線上幾毫米,接著用吸管將多餘的液體吸出。
滴定管(包括旋塞閥和流液口)用(yong)蒸(zheng)餾(liu)水(shui)清(qing)洗(xi)後(hou),再(zai)用(yong)待(dai)用(yong)的(de)試(shi)液(ye)衝(chong)洗(xi)三(san)次(ci)。如(ru)果(guo)滴(di)定(ding)管(guan)尺(chi)寸(cun)不(bu)夠(gou)大(da),其(qi)頂(ding)部(bu)插(cha)不(bu)進(jin)溫(wen)度(du)計(ji)用(yong)於(yu)觀(guan)測(ce)液(ye)體(ti)溫(wen)度(du),可(ke)設(she)置(zhi)一(yi)根(gen)足(zu)以(yi)容(rong)納(na)溫(wen)度(du)計(ji)的(de)普(pu)通(tong)玻(bo)璃(li)試(shi)管(guan)夾(jia)在(zai)滴(di)定(ding)管(guan)旁(pang)邊(bian)。
將jiang夾jia在zai垂chui直zhi位wei置zhi的de滴di定ding管guan充chong水shui至zhi零ling線xian以yi上shang幾ji毫hao米mi,如ru果guo管guan壁bi沾zhan濕shi,則ze在zai調tiao定ding零ling線xian以yi前qian應ying有you充chong分fen的de瀝li液ye時shi間jian,為wei了le排pai除chu旋xuan塞sai閥fa和he流liu液ye口kou間jian氣qi泡pao,在zai調tiao定ding零ling線xian之zhi前qian應ying從cong流liu液ye口kou排pai放fang一yi些xie液ye體ti再zai注zhu液ye。
流(liu)出(chu)時(shi)間(jian)是(shi)指(zhi)當(dang)旋(xuan)塞(sai)閥(fa)全(quan)開(kai)時(shi)液(ye)體(ti)從(cong)零(ling)線(xian)至(zhi)標(biao)稱(cheng)容(rong)量(liang)自(zi)由(you)流(liu)出(chu)所(suo)用(yong)的(de)時(shi)間(jian)。為(wei)了(le)得(de)到(dao)最(zui)佳(jia)準(zhun)確(que)度(du),應(ying)使(shi)用(yong)分(fen)度(du)修(xiu)正(zheng)值(zhi)。在(zai)放(fang)液(ye)時(shi)旋(xuan)塞(sai)閥(fa)應(ying)全(quan)開(kai),流(liu)液(ye)口(kou)不(bu)得(de)與(yu)接(jie)收(shou)容(rong)器(qi)及(ji)液(ye)麵(mian)接(jie)觸(chu)。因(yin)此(ci),對(dui)滴(di)定(ding)管(guan)來(lai)說(shuo),最(zui)好(hao)能(neng)估(gu)算(suan)出(chu)試(shi)樣(yang)需(xu)耗(hao)用(yong)多(duo)少(shao)毫(hao)升(sheng)溶(rong)液(ye)方(fang)可(ke)到(dao)達(da)終(zhong)點(dian),如(ru)果(guo)有(you)足(zu)夠(gou)的(de)試(shi)樣(yang)可(ke)進(jin)行(xing)一(yi)次(ci)預(yu)先(xian)的(de)滴(di)定(ding)來(lai)得(de)到(dao)這(zhe)一(yi)點(dian)。如(ru)果(guo)不(bu)能(neng)這(zhe)樣(yang)做(zuo),隻(zhi)要(yao)滴(di)定(ding)時(shi)間(jian)不(bu)超(chao)過(guo)規(gui)定(ding)流(liu)出(chu)時(shi)間(jian)60s,則在容量允差為±t mL 時,所產生的誤差一般小於±t m L。如(ru)果(guo)規(gui)定(ding)了(le)等(deng)待(dai)時(shi)間(jian)則(ze)為(wei)旋(xuan)塞(sai)閥(fa)關(guan)閉(bi)後(hou)與(yu)最(zui)後(hou)讀(du)數(shu)之(zhi)前(qian)的(de)那(na)段(duan)時(shi)間(jian),通(tong)常(chang)不(bu)得(de)在(zai)滴(di)定(ding)進(jin)行(xing)時(shi)觀(guan)測(ce)等(deng)待(dai)時(shi)何(he),因(yin)為(wei)達(da)到(dao)滴(di)定(ding)終(zhong)點(dian)的(de)時(shi)間(jian)一(yi)般(ban)比(bi)規(gui)定(ding)的(de)等(deng)待(dai)時(shi)間(jian)長(chang)。
上(shang)述(shu)使(shi)用(yong)情(qing)況(kuang)適(shi)用(yong)於(yu)粘(zhan)度(du)與(yu)水(shui)相(xiang)似(si)的(de)透(tou)明(ming)液(ye)體(ti),特(te)別(bie)粘(zhan)稠(chou)的(de)液(ye)體(ti)不(bu)能(neng)準(zhun)確(que)而(er)方(fang)便(bian)地(di)使(shi)用(yong),因(yin)為(wei)這(zhe)樣(yang)會(hui)在(zai)管(guan)壁(bi)上(shang)留(liu)下(xia)大(da)量(liang)的(de)粘(zhan)液(ye),而(er)且(qie)流(liu)速(su)很(hen)慢(man),但(dan)是(shi)通(tong)常(chang)用(yong)於(yu)容(rong)量(liang)分(fen)析(xi)的(de)稀(xi)釋(shi)水(shui)溶(rong)液(ye)是(shi)適(shi)用(yong)的(de),而(er)且(qie)無(wu)明(ming)顯(xian)的(de)誤(wu)差(cha)。例(li)如(ru):1mol/L 的溶液產生的誤差小於A 級的允差。而0.1mol/L 的溶液則產生的誤差相應更小。當使用非水液體時準確度也會降低,因為它們的表麵張力與水的表麵張力相差很大。對於彎液麵底部可見度較差的液體,可在彎液麵上邊緣讀數,但比在彎液麵最低點觀測到的準確度要差些。
吸量管yongzhengliushuiqingxizhihou,zaiyongdaiyongyetichongxi。xiliangguanxiquyetizhilingbiaoxianyishanghuosuoxukeduxianyishangjihaomi。jianyishiyongnengshidaiceyetiziyouliudongdexiju,ruxiqiudeng。
weilededaozhengquedeliangchurongliang,xiliangguanyinganqichanpinbiaozhunzhongyouguanrongliangdingyisuoshudefangfacaozuo。xiliangguanyujieshourongqituolizhiqian,yingzunshouguidingdedengdaishijian。tongchangxiliangguanguabiyetiliuzhiliuyekoudedengdaishijianguiding3syizugoule,erqiebuxuyaozhunqueceding。yidanquedingwanyemiandadaoliuyekoubingquyujingzhi,xiliangguanjikeyujieshourongqituolijiechu。liuzailiuyekoudeyuyebudepaichu,er“吹出”shixiliangguanzeyingchuichuqizuihouyuyezuoweiliangchurongliangdeyibufen。yudidingguanyiyang,feichangzhanchoudeyetibunengfangbianhezhunquedixiqu。tongchangyongyurongliangfenxidexishishuirongyeshishiyongde,erqiewumingxianwucha。
yongzhengliushuiqingxizhihoujinxingganzaohuoyongdaicerongyechongxisanci。xiquyetizhilingbiaoxianyishanghuosuoxukeduxianyishang。weilededaozhengquedeliangrurongliang,xiliangguanyinganyouguanrongliangdingyisuoshufangfacaozuo。
本(ben)文(wen)所(suo)述(shu)的(de)操(cao)作(zuo)主(zhu)要(yao)是(shi)需(xu)要(yao)和(he)校(xiao)準(zhun)計(ji)量(liang)玻(bo)璃(li)容(rong)器(qi)時(shi)保(bao)持(chi)一(yi)致(zhi),一(yi)般(ban)來(lai)說(shuo)操(cao)作(zuo)和(he)校(xiao)準(zhun)時(shi)保(bao)持(chi)一(yi)致(zhi)會(hui)更(geng)大(da)程(cheng)度(du)保(bao)證(zheng)準(zhun)確(que)度(du)和(he)校(xiao)準(zhun)一(yi)致(zhi)的(de)狀(zhuang)態(tai)。
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