化學(xué)檢驗(yàn)工操作試題-計(jì)算題

1、化學(xué)檢驗(yàn)工操作計(jì)算題1.用Na2B4O710H2O標(biāo)定HCl溶液的濃度，稱取0.4806g硼砂，滴定至終點(diǎn)時(shí)消耗HCl溶液25.20mL，計(jì)算HCl溶液的濃度。（M(Na2B4O710H2O)=381.37）解：Na2B4O72HCl5H2O＝4H3BO32NaCln(Na2B4O7)=(12)n(HCl)(mM)(Na2B4O710H2O)=(12)(cV)(HCl)c(HCl)=0.1000molL2.要求在標(biāo)定時(shí)用去0.20mol

2、LNaOH溶液20～25mL，問應(yīng)稱取基準(zhǔn)試劑鄰苯二甲酸氫鉀（KHP）多少克？如果改用二水草酸作基準(zhǔn)物質(zhì)，又應(yīng)稱取多少？（M(KHP)=204.22，M(二水草酸)=126.06）解：n(KHP)=n(NaOH)(mM)(KHP)=(cV)(NaOH)n(H2C2O42H2O)=(12)n(NaOH)(mM)(二水草酸)=(12)(cV)(NaOH)由此可計(jì)算得：需KHP稱量范圍為：0.82～1.0g，需二水草酸稱量范圍為：0.25～0

3、.32g。3.一組重復(fù)測(cè)定值為15.6715.6916.0315.89。求15.67這次測(cè)量值的絕對(duì)偏差和相對(duì)偏差，這組測(cè)量值的平均偏差、相對(duì)平均偏差、標(biāo)準(zhǔn)偏差及相對(duì)標(biāo)準(zhǔn)偏差。解：=(15.6715.6916.0315.89)4=15.82X15.6715.820.15idXX??????0.15100%100%0.95%15.82dRdX???????10.150.130.210.070.144niiXXdn?????????0.14

4、100%0.89%15.82dRdX??????2222210.150.130.210.070.1713niiXXSn??????????因此%14.0%04.355%11.078.2%04.35????????nstxfp?6.用K2Cr2O7基準(zhǔn)試劑標(biāo)定Na2S2O7溶液的濃度（molL1），4次結(jié)果為：0.1029，0.1056，0.1032和0.1034。（1）用格魯布斯法檢驗(yàn)上述測(cè)定值中有無可疑值（P=0.95）；（2）比較置

5、信度為0.90和0.95時(shí)μ的置信區(qū)間。（G0.954=1.46，，）92.2290.0?t0.9524.30t?解：(1)1038.041056.01034.01032.01029.0??????x0011.0140018.00004.00006.00009.0122222?????????ndsi82.00011.01029.01038.011??????sxxG64.10011.01038.01056.041??????sxxGG

6、1G0.954故0.1056這一數(shù)據(jù)應(yīng)舍去。(2)1032.031034.01032.01029.0?????x00025.0130002.00003.01222???????ndsi當(dāng)P=0.90時(shí)，因此92.2290.0?t0004.01032.0300025.092.21032.01????????nstxfp?當(dāng)P=0.95時(shí)，因此0.9524.30t?0006.01032.0300025.030.41032.01???????