推 srwff :化學系已收 05/08 23:18
課程名稱︰分析化學丁
課程性質︰生科系一年級必修
課程教師︰劉春櫻
開課學院：理學院
開課系所︰化學系
考試日期（年月日）︰2009.05.04
考試時限（分鐘）：120 min
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1. Define (18%)
(a) Conditional formation constant
(b) Reference electrode
(c) Indicator electrode
(d) Monochromator
(e) Junction potential
(f) Salt bridge
2. Describe the source of pH-dependence in a glass membrane electrode. (6%)
3. List several sources of uncertainty in pH measurements with a glass/calomel
electrode system. (6%)
4. Calculate the dissociation constant for the weak acid HP, if the cell
SCE∥HP(0.010M),NaP(0.040M)∣Pt,H2(1.00atm)
develops a potential of -0.591V
(Note:Esce = 0.244V) (10%)
5. Why is a small amount of Mg-EDTA complex often added to a water specimen
that is to be titrated for hardness? (5%)
6. Calculate pMg2+ at the equivalence point for the titration of 50.0mL of 0.05M
Mg2+(buffered to pH 10.00) with 0.050M EDTA.(Note:Kf for MgY2- is 6.2 x 10^8;
αγ4- at pH 10.00 is 0.30.) (6%)
7. The following data are the volume relationships in the analysis of mixture
containing NaOH, NaHCO3 and Na2CO3. Give the corresponding constituents in
sample. (where Vphth = volume of acid needed for a phenolohthalein end point;
Vbcg = volume of acid needed for a bromocresol green end point.)
(a) Vphth = Vbcg (b) Vphth =1/2 Vbcg (c) Vphth = 0, Vbcg > 0
(d) Vphth > 1/2 Vbcg (e) Vphth < 1/2 Vbcg
(Note:1.acid dissociation constants for carbonic acid, H2CO3 are 4.45 x 10^-7
; 4.69 x 10^-11. 2.Transition range for bromocresol green: 3.8-5.4; that for
phenolphthalein: 8.0-9.6) (15%)
8. Give the equations to illustrate how to determine the nitrogen content in the
protein with Kjeldahl method. (12%)
9. Here are the titration curves for three different diprotic acids. Please
explain each of them. (6%)
(附圖)
10.Use activities to calculate the hydronium ion concentration in a 0.120 M
solution of HNO2 that is also 0.050 M in NaCl. (Note:the thermodynamic
constant of HNO2 is 5.1 x 10^-4) (12%)
11.State the difference between transmittance, absorbance and molar absorptivity
Which one is proportional to concentration? (5%)
12.(a) How to standardize a nitrite solution? (b) Give the procedures to
determine the aquarium nitrite constant based on the following reaction with
a spectrophotometric analysis. (c) Give the methods to analyze the mixture of
nitrate and nitrite. (18%)
(附(b)的反應式)
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