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1、K称取0.2562gNa2CO3标准物质溶于水后，以甲基橙做指示剂，用HCI滴定，终点时用去HC122・82ml,求此HC1浓度和T(HCl/Na2CO3)oM(Na2CO5)=106.0g/molm^coiMNa2CO3=^xChcixVhci0.2562106.0HCIx22.80x10'3hci=0.2120mol/LTnd/Na2CO3mNa2CO3a__1bn(Na2S2O3)6=£xc(^5QQ)M(K2Cr2O.)b-232301908=-xc(M/5OJx33.46x10一3294.26…'c(Na2S2O^)=
2、0.1163(mol/L)5、测定工业用纯碱Na2CO3的含量，称取0.2560g试样，用0.2000mol/LHC1溶液滴定。若终点时消耗HC1溶液22.93mL,问该HC1溶液对Na2CO3的滴定度是多少?计算试样中Na2CO3的质量分数。M(Na2CO?)=106.0g/mol0.256222.80=0.01124g/mL或^HCl/Na,^=yXCHC1X1O'xM^CC^1.=-x0.2120x10"3x106.02=0.01124g/mLTHci/Na2coy=^c(HCl)xM(Na2CO3)x10-3=丄X0.2
3、000X106.0X10-3=0.01060(g/mL)THCllNaC()V(HCl)co(Na£O)=""——Ix100%一W2、称取含铁试样0・3000g,溶于酸，并把诙全部还原为Fc叭/IJ0.02000mol/I.K2Cr2O7溶液滴定，用去22.00mL,计算T(K2Cr2O7/Fe2O3)和试样中Fe?。)质量分数。(M0・01060x22.930.2560X100%=94.94%卜©0尸159.69g/mol)6>0.5000gMgO试样中加入0.2645mol/LHCI标准溶液48.00mL,过虽的HCI用O.
4、lOOOmol/LNaOHlul滴，用去NaOH14・35mL,求试样中MgO%。M(MgO)=40・30g/molnFe-CHC1XVrci1M,IgO17XCNaOHXVzaOH0.2645x48.00xl0--
5、x^+lx0.1000xl4.35xl0-mFe,O33vM1Cr2O7-Cr2O721V1Fe2O31mMgo=°・2269gmFpn32F°2-3-=-x0.02000x22.00xlO'3159.691^MgO二卷糾00%"38%mFe2o5=0.2108g=^xl00%=70-27%3、标定NaOH标准溶液
6、时称取邻苯二川酸氢钾(KHP)基准物质0.4925gn若终点时川去NaOH溶液23.50mL,求NaOH溶液的浓度。M(KHP)-204.2^mola_n(KHP)1b~n(NaOH)~17、将l.OOOg钢样中Cr氧化成Cr2O72*,jjllA25.00ml0」OOOmol/LFcSO4标准溶液,然后用0.01800mol/LKMn04标准溶液7.00mL回滴过量的FeSO4>计算钢中Cg%。M(CdOJ-152.0g/mol〃(屉2+)_c_6n(Cr2O/)a1n(Fe2+)_c^_5n(KMnO,)~~b~m(KHP
7、)M(KHP)=-xc(NaOH)xV(NaOH)b器十认°H)x23.50x”c(NaOH)=0.1026(mol/L)4、在含0.1908g纯的K2Cr2O7液中加入过量的KI和II2SO4＞析出的I2用Na2S2O3溶液滴定，用去33・46mL,求Na2S2O5的浓度。M(K2Cr2O7)=294.2g/molc(FeSO4)V(FeSO4)=0.1000x25.00x1O'3=6x"d)+5%c(KMnO4)V(KMnOA)M(Cr2O3)=6X”02°3)+5xo.o1800X7.00X10-3152.00m(Cr)=
8、0.04737gco(Cr)=0.047371.000X100%=4.737%1、0.1000mol/LNH.vH2020.00ml(i2^心(NHsHOPl・8xl0$)用同浓度的HC1來滴定，计算未滴定前、计量点前半滴、计量点、计量点后半滴溶液pH值。选择指示剂并指明指示剂颜色变化。滴定前：NII3-H2O[OH十应=71.8x10~5x0.1=1.3x10-3pOH=-lg[OH_]=-lg1.3x1O'3=2.87pH=11」3计量点前半滴(0.02mL)：NH3(0.02mL)+NH41(19.98mL)pOH=-lg
9、[OH']=-lg5.3xl0-6=5.28pH=14-pOH=14-5.28=8.72计虽点后半滴:NaOH+Ac(0.02mLNaOH)[OH十CNaOHV>jaOH0.1x0.02nh3-nh/40.02=5.0x10-5PH=PK3NH/+lg[NHJ[
