課程名稱︰分析化學乙上
課程性質︰醫技系必修
課程教師︰林萬寅
開課系所︰化學系
考試時間︰94上期末
試題 :
1.
(a) Find the isoelectric and isoionic pH of 0.010 M leucine(pK1=2.33, pK2=9.75)
(b) Explain how isoelectric focusing works.
2.
A 50.0 mL aliquot of 0.100 M diprotic acid H2A(pK1=3.0, pK2=6.0) was titrated
with 0.10 M NaOH. Find the pH at the following volumes of base added.
(a)30.0 mL (b)50.0 mL (c)100.0mL
3.
A 50.0 mL aliquot of 0.0500 M metal ion M buffered at pH 9.00 was titrated
with 0.0500 M EDTA. Find the pM at the following volumes of EDTA added.
(log Kf=14.00 for M-EDTA complex; αy=0.054 at pH 9.00)
(a)20.0 mL (b)50.0 mL (c)55.0 mL
4.
Consider the titration of 50.0 mL 0.050 M Sn(Ⅱ) by 0.10 M Ce(Ⅳ) in 1 M HCl,
using Pt and SCE as the indicator(cathode) and reference electrode,
respectively. (Ef=0.14 V for Sn(Ⅳ)→Sn(Ⅱ), 1.47 v for Ce(Ⅳ)→Ce(Ⅱ);
E-ref=0.241 V)
(a) Write the titration reaction
(b) Write the two cell reactions
(c) Find the cell potentials after addition of 20.0, 50.0, 60.0 mL of Ce(Ⅳ)
solution.
5.
The cell SCE∥cathodic solution｜Hg(l) develops a potential of -0.016V. The
cathodic solution was prepared by mixing 50.0 mL of 0.100 M EDTA buffered at
pH 9.0 with 50.0 mL 0.0400 M Hg(ClO4)2. Find the formation constant of
Hg(EDTA)
(E=0.852 V for Hg(Ⅱ)→Hg)
6.
Answer the following questions.
(a) Explain the difference between faradaic current and charging current.
(b) Draw the Voltage-scan profile for the square wave voltammetry. Why is
square wave voltammetry more sensitive than sampled-current voltammetry?
(c) Explain what is done in anodic stripping voltammetry. Why is stripping
the most sensitive polarographic technique?
(d) What is a junction potential? Why is the junction potential of 0.1 M
HCl∣0.1 M KCl of opposite sign and grater magnitude than that of
0.1 M NaCl∣0.1 M KCl?
(e) Describe the acid error and the alkaline error of glass electrode.
(f) Explain the principle of operation of ion-selective electrodes.
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