酸堿滴定終點誤差計算法ppt課件

1、酸堿滴定終點酸堿滴定終點誤差計算法誤差計算法徐海超徐海超TE= -終點時剩余被滴定物質(zhì)的量化學(xué)計量點時應(yīng)加入的滴定劑的量*100終點誤差定義為：終點誤差定義為：_CxepCx=TE*100%在化學(xué)計量點時滿足：得質(zhì)子產(chǎn)物得質(zhì)子產(chǎn)物 sp= 失質(zhì)子產(chǎn)物失質(zhì)子產(chǎn)物sp終點時：+ _ (得質(zhì)子產(chǎn)物 ep - 失質(zhì)子產(chǎn)物ep )Cx =q強酸強堿的滴定 H+sp = OH-spv以HCl滴定NaOH為例化學(xué)計量點時：終點時：e ep pC Cx x= =T TE E* *1 10 00 0% % H H+ + e ep p - - O OH H- - e ep pCx = H+ep - OH-epH+

2、sp = OH-sp +B-sp q強酸滴定弱堿B-化學(xué)計量點時： Cx = H+ep - OH-ep - B-epCx = H+ep - B-ep忽略O(shè)H-ep e ep pC Cx x= =T TE E* *1 10 00 0% % H H+ + e ep p - - B- e ep pCx = HPO42-sp1 -H+sp1 - H3PO4spq多元酸堿以NaOH滴定H3PO4為例 H+sp1 +H3PO4sp1 = OH-sp1 +HPO4-sp1 + 2PO43-sp1 v化學(xué)計量點時：v忽略O(shè)H-， PO43-e ep p1 1C Cx x= =T TE E* *1 10 00

3、0% % H HP PO O4 42 2- - s sp p1 1 - - H H+ + s sp p1 1 - - H H3 3P PO O4 4 s sp p1 1H+sp = NH3 sp+ OH-sp NaOH滴定滴定HCl, NH4Cl混合溶液中的混合溶液中的HClq混合酸堿 化學(xué)計量點時：Cx = NH3ep - H+epe ep pC Cx x= =T TE E* *1 10 00 0% %NH3ep - H+ep結(jié)論結(jié)論Q寫出化學(xué)計量點是的質(zhì)子條件Q做適當(dāng)?shù)暮雎訯將質(zhì)子條件等式一邊減去另一邊得到 Cx，代入誤差計算公式Q根據(jù)相關(guān)條件幾算出各形體濃度，從 Q 而計算出滴定誤差 w H+ep + HB ep Caep = OH- ep w Caep HB ep = H+ ep OH- epw Caep (CBep B- ep) = H+ ep OH- epw Caep CBep = H+ ep OH- ep B- epw + _ (得質(zhì)子產(chǎn)物 ep - 失質(zhì)子產(chǎn)物ep )Cx =忽略忽略 OH- ep OH- e