資料分析化學(xué)chap3

Titrimetric1.SomegeneralaspectsofTitrimetric1.Somegeneralaspectsof2.Classificationoftitrimetric3.PrimarystandardandStandard4.Volumetric1.Somegeneralaspectsof1-11.Somegeneralaspectsof1-1Titrimetry（TitrimetricanalysisTitrimetricmethods(volumetricmethods)includealargeandpowerfulgroupofquantitativeproceduresthatarebaseduponmeasuringtheamountofareagentofknownconcentrationthatisconsumedbytheanalyte.返–標(biāo)準(zhǔn)溶液中，直到所加的試劑與被測物質(zhì)按化學(xué)–標(biāo)準(zhǔn)溶液中，直到所加的試劑與被測物質(zhì)按化學(xué)1.Somegeneralaspectsof1-2Some(滴定準(zhǔn)1.Somegeneralaspectsof1-2Some(滴定準(zhǔn)確裝在滴定管中的另一種溶液逐滴加入到被測溶液中的操作standardsolution（標(biāo)準(zhǔn)溶液）：(待測液待測定的物質(zhì)1.Somegeneralaspectsofsp，化學(xué)計(jì)量點(diǎn)(Equivalence1.Somegeneralaspectsofsp，化學(xué)計(jì)量點(diǎn)(Equivalence point（ep，滴定終點(diǎn)（指示劑 error（Et，滴定誤差1.Somegeneralaspectsofeg：HCl+Na21.Somegeneralaspectsofeg：HCl+Na2CO3=2NaCl+H2O+Indicator：甲基橙 **滴定分析通常用于測定常量組分，即被測組分的含量一般在1%以上。測定2.Classificationoftitrimetric2-1Requirementforthe2.Classificationoftitrimetric2-1Requirementforthechemicalquantitativereaction（>2.Classificationoftitrimetric2-2classification(chemicalreaction1Acid-base2Complex2.Classificationoftitrimetric2-2classification(chemicalreaction1Acid-base2Complex3Oxidation/Reduction4PrecipitationAg++ →Cr2O72-+6Fe2++14H→2Cr3++6Fe3+++Zn2++H2Y2-→ZnY2-+H++ →2.Classificationoftitrimetric2-3classification(Titration?Direct2.Classificationoftitrimetric2-3classification(Titration?Direct?Back?Replacement?Indirect2.ClassificationoftitrimetricBack?DeterminationofAl3+Al3++2.ClassificationoftitrimetricBack?DeterminationofAl3+Al3++EDTA（excess）Al3+-EDTA+standardsolutionEDTA（overplus）Zn2+-+standardsolutionC1V1-C2V2contentof2.Classificationoftitrimetric?Replacement2.Classificationoftitrimetric?Replacement在酸性條件下，硫代硫酸鈉不能直接滴定重鉻酸鉀及其它氧化劑，因?yàn)檫@些氧化劑將S2O32-氧化成及SO4 Cr2O72-+6I-+ 2Cr3++3I2+I2+ 2I-+3.PrimarystandardandStandard3-13.PrimarystandardandStandard3-1somePrimaryahighlypurifiedcompoundthatservesasareferencematerialforatitrimetricmethodofanalysis.Standardsolution：asolutionwithknown3.PrimarystandardandStandard3-2PrimaryImportant因?yàn)槟栂?.PrimarystandardandStandard3-2PrimaryImportant因?yàn)槟栂嗤瑫r(shí)，如果試差如M=300,M=ABA相對誤差B相對誤差molarmassQuantitativeAbsenceofhydrateStabilitytowardHigh3.PrimarystandardandStandard3.PrimarystandardandStandard標(biāo)定標(biāo)定還原劑：K2Cr2O7，標(biāo)定AgNO3：acid-3.PrimarystandardandStandard級一二三中英標(biāo)綠3.PrimarystandardandStandard級一二三中英標(biāo)綠紅藍(lán)3.PrimarystandardandStandard3-3Standard3.PrimarystandardandStandard3-3Standard?3-3ADesirablepropertiesofstandardReact3.PrimarystandardandStandard3-3BMethodsforestablishingtheconcentrationofstandardsolutionPreparationof3.PrimarystandardandStandard3-3BMethodsforestablishingtheconcentrationofstandardsolutionPreparationofstandardmethod：準(zhǔn)確稱取一定量的基準(zhǔn)物質(zhì)，溶后配成一定體積的溶液，根據(jù)物質(zhì)質(zhì)量和溶液體積，可計(jì)算出該標(biāo)準(zhǔn)溶液的準(zhǔn)確濃度(如Na2B4O710H2O ?1Lvolumetric3.PrimarystandardandStandardIndirectmethod(standardizedmethod)3.PrimarystandardandStandardIndirectmethod(standardizedmethod)：不能直接配制標(biāo)準(zhǔn)溶液的物質(zhì)，可先粗略稱取一定量物質(zhì)（或量取一定體積溶液），配制成一種近似于所需濃度的溶液，然后再用基準(zhǔn)物質(zhì)或另一種物質(zhì)的標(biāo)準(zhǔn)溶液來標(biāo)定它的準(zhǔn)確濃度（如HCl、NaOH、EDTAetc.）標(biāo)定時(shí)注意：標(biāo)定次數(shù)不少于3次，標(biāo)定時(shí)的操作條3.PrimarystandardandStandard3-3CMethodsforexpressingtheconcentrationofstandardsolutionmol,物質(zhì)的量nB3.PrimarystandardandStandard3-3CMethodsforexpressingtheconcentrationofstandardsolutionmol,物質(zhì)的量nB摩爾質(zhì)量MBM(B)gmol-cBc(B)molL-(mol.L1)nB(mol)nBcBVmBVn(mol)BMB3.PrimarystandardandStandardA/)TA/B3.PrimarystandardandStandardA/)TA/BA：被滴定的物質(zhì)B例如用來測定Fe的K2Cr2O7標(biāo)準(zhǔn)溶液，其滴定=0.005000gmL-1TFe/指每mLK2Cr2O7恰好與0.005000g的Fe反應(yīng)。如果在滴定中消耗 gmL-1×21.50mL=0.10753.PrimarystandardandStandardTA/BcB的關(guān)系aA+bB=cC+dannABbmaAcVBMbAamV1mLMcVAAB3.PrimarystandardandStandardTA/BcB的關(guān)系aA+bB=cC+dannABbmaAcVBMbAamV1mLMcVAABba3TMc()A/ABb4.Volumetric4-滴定劑B與被測物質(zhì)A之間的計(jì)量aA+bB=4.Volumetric4-滴定劑B與被測物質(zhì)A之間的計(jì)量aA+bB=cC+d注：多個(gè)反應(yīng)式時(shí)確定計(jì)量關(guān) a 溶 acBV AmA ac A b a 4.Volumetric–氟硅酸鉀法測定SiO2時(shí)，先將SiO2處理成可溶性4.Volumetric–氟硅酸鉀法測定SiO2時(shí)，先將SiO2處理成可溶性H2SiO3，在酸性介質(zhì)中加入KF，過量KCl存在下，形成K2SiF6沉淀，沉淀在沸水中水解，生成HF，用NaOH標(biāo)液滴定生成的HF，從而確定4.Volumetric H2SiO3 4.Volumetric H2SiO3 K23H2K2SiF63H2O4HFH2SiO HFNaOHNaFH~1molH2SiO~~21nSiO44.Volumetric4-2、ContentofanalyteaA+bB=cC+d acV AAA4.Volumetric4-2、ContentofanalyteaA+bB=cC+d acV AAA AbAmsWeightacV A100Weight或：ATAeg. WhatisthemolarityofK+inanaqueoussolutionthatcontains63.3ppmofK3Fe(CN)eg. WhatisthemolarityofK+inanaqueoussolutionthatcontains63.3ppmofK3Fe(CN)6(329.2g/mol)?31.005.77104mol/cKeg.Calculatethemolareg.CalculatethemolarconcentrationofHNO3(63.0g/mol)inasolutionthathasaspecificgravityof1.42andis70%HNO3(w/w).g 1.42greagent103mL70g3100gLmLg 1.42greagent103mL70g3100gLmL994gLL1mol994gcL15.863.0g3eg. TostandardizetheHClsolution,aprimarystandardNa2B4O710H2Oeg. TostandardizetheHClsolution,aprimarystandardNa2B4O710H2Owasdissolvedand21.20mLHClsolutionwasrequiredtothestoichiometricpoint.CalculatethemolarityoftheHClsolution.Na2B4O72HCl5H2O4H32nNaBO10H BO10Hc 2MNaBO10HO 220.1165mol381.3721.20eg.Themolarityoftheeg.Themolarityofthesolutionis0.01667mol.L-，（1）Fe/K2Cr2O7,TFe2O3/K2Cr2O7,TFe3O4/（2）a0.4500gsampleofironore,V(K2Cr2O731.62mL,calculatethepercentFe2O3 intheore。解6Fe2Cr2O14Hn2CrO72解6Fe2Cr2O14Hn2CrO726n61O=2 3211O=Cr n=(a/b)cBMVTA/K KTwAmsM(Fe)=55.85,M(Fe2O3)=159.7,M(Fe3O4)=M(Fe)=55.85,M(Fe2O3)=159.7,M(Fe3O4)=Cr MFe30.01667T Fe2O3/KTFeO/KCrO Cr K wFem s0.00798631.62100%eg. 基準(zhǔn)物eg. 基準(zhǔn)物質(zhì)標(biāo)定0.020mol.L-1的Na2S2O30.1(V=25 Na2S2O3 K解1mMK6K1(CV6MEr解1mMK6K1(CV6MErK0.1，須稱取10倍量的基準(zhǔn)物質(zhì)，即0.25g2501(0.02025) 0.025(eg. 稱取鐵礦石試樣0.5000g，將其溶解，使全部鐵還原0eg. 稱取鐵礦石試樣0.5000g，將其溶解，使全部鐵還原0501點(diǎn)時(shí)，用去2Cr27標(biāo)準(zhǔn)溶液23.45mL，求試樣中Fe和3–6Fe2+ = n6n61O=2 nFe31=Cr 6nKCr6cKCrVnFeFeKCrFe mmm6nKCr6cKCrVnFeFeKCrFe mmmsss60.0150023.4510355.85MFeMFenFeOCrOw mmss30.0150023.45