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學年上學期期中考
試題 :
1.
If you want to prepare 500 mL of 0.1 M Na2CO3 (Fw=106.0) solution from a stock
solution of {21.2(±0.2)}% (by weight) Na2CO3 having density of 1.25 (±0.02)
g/mL.
(a) Find the volume of the stock solution needed.
(b) If the uncertainty in delivering the Na2CO3 stock solution is ±0.02 mL,
find the molarity of the Na2CO3 solution (the significant figure and
uncertainty must be considered). Assume negligible uncertainty in molar
mass of Na2CO3 and in the final volume, 500mL.
2.
The calcium content of a person's urine was determined on two different days.
┌─────┬───────┬────────────┐
│ Day │ Ca(mg/mL) │ No. of observations │
├─────┼───────┼────────────┤
│ 1 │ 238±6 │ 4 │
├─────┼───────┼────────────┤
│ 2 │ 258±5 │ 6 │
└─────┴───────┴────────────┘
Are the average value different at 90% confidence level? at 99% confidence
level?
3.
Using the Q test, decide whether the value 0.195 should be rejected from the
set of results 0.224, 0.222, 0.220, 0.218, 0.216, 0.195. Calculate the
confidence limit of these results at 95% confidence level.
4.
Find the solubility of Mg(OH)2 in an aqueous solution fixed at an ionic
strength of 0.090 by adding an inert salt. Ksp = 6.0*10^-10 for Mg(OH)2;
hydrated radius = 800 pm for Mg(Ⅱ) and 350 pm for OH¯.
5.
(a) Find the pH of 0.1 M HA (pKa = 5.0) solution.
(b) What is the pH of the solution prepare by mixing 50.0 mL, 0.1M HA with
30 mL, 0.1M NaOH?
6.
Describe the methods of Vlhard, Fajans, and Mohr for the precipitation
titration involving AgNO3.
7.
Calculate the solubility of CaCO3 in aqueous solution at pH 4.0. Write the
charge balance equation, the mass balance equation(s), and all pertinent
equilibrium constaant expressions.(pK1 = 6.35 and pK2 = 10.33 for H2CO3)
8.
Explain the following terms.
(a) precision and accuracy
(b) peptization
(c) homogeneous precipitation
(d) buffer capacity
(e) determinate and indeterminate errors
附錄:
values of Student's t
┌─────────┬───────────────────────┐
│ Degrees │ ꄠ Confidence level(%) │
│ ꄠ of ├─────┬─────┬─────┬─────┤
│ freedom │ 50 │ 90 │ 95 │ 99 │
├─────────┼─────┼─────┼─────┼─────┤
│ 1 │ 1.000 │ 6.314 │ 12.706 │ 63.657 │
│ 2 │ 0.816 │ 2.920 │ 4.303 │ 9.925 │
│ 3 │ 0.765 │ 2.353 │ 3.182 │ 5.841 │
│ 4 │ 0.741 │ 2.132 │ 2.776 │ 4.604 │
│ 5 │ 0.727 │ 2.015 │ 2.571 │ 4.032 │
│ 6 │ 0.718 │ 1.943 │ 2.447 │ 3.707 │
│ 7 │ 0.711 │ 1.895 │ 2.365 │ 3.500 │
│ 8 │ 0.706 │ 1.860 │ 2.306 │ 3.355 │
│ 9 │ 0.703 │ 1.833 │ 2.262 │ 3.250 │
│ 10 │ 0.700 │ 1.812 │ 2.228 │ 3.169 │
└─────────┴─────┴─────┴─────┴─────┘
Q values
┌─────────┬───────┐
│ Q │ Number of │
│(90% confidence) │ observations │
├─────────┼───────┤
│ 0.94 │ 3 │
│ 0.76 │ 4 │
│ 0.64 │ 5 │
│ 0.56 │ 6 │
│ 0.51 │ 7 │
│ 0.47 │ 8 │
│ 0.44 │ 9 │
│ 0.41 │ 10 │
│ 0.39 │ 11 │
└─────────┴───────┘
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※ 編輯: dabi 來自: 218.167.160.131 (01/22 17:47)