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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