推 chitanes:...啊...有重複喔...= = 11/14 21:58
推 asdScott:嗯，他之前考三次... 11/14 23:26
上面那篇只貼了第一次期中考的吧
不過在考古題板上
93年的期中考有兩次
而且第二次的範圍跟我們這次要考的也有重複
所以我就把他貼過來了
就是這樣
祝大家考試順利
(;>口<; 嗚啊~物化要怎麼辦呀呀呀)
標題: [試題] 93上劉春櫻分析化學第二次期中考
時間: Wed Dec 1 18:06:02 2004
Nov.29, 2004 Analytical Chemistry
1.Define the following terms:(15%)
a)coprecipitation b)post precipitation
c)homogeneous precipitation(explain it briefly and give an example)
d)isoionic point e)buffer capacity
2.A procedure was used in which electric current in a detector is proportional
to analyte concentration. From previous measurements of a low concentration
of analyte, the signal detection limit was estimated to be in the low
nanoampere range. Signals from seven replicate samples with a concentration
about three times the detection limit were 5.0,5.0,5.2,4.2,4.6,6.0 and 4.9nA.
Reagent blanks gave values of 1.4,2.2,1.7,0.9,0.4,1.5 and 0.7nA. The slope of
the calibration curve for higher concentrations is m=0.229nA/μA. (a)Find the
signal detection limit and the minimum detectable concentration. (b)What is
the concentration of analyte in a sample that gave a signal of 7.0nA? (12%)
3.a)How to prepare a carbonate free NaOH solution? b)Give the name and formula
of a primary standard used to standardize (1)HCl and (2)NaOH. c)Why is it
more accurate to use a primary standard with a high equivalent mass than one
with a low equivalent mass? d)Could the strongly basic solutions be stored
in glass containers? If not, please give the reason and state how to solve
the problem. (8%)
4. What is a Gran plot used for? (10%)
5. What is meant by the leveling effect? (3%)
6. The base B is too weak to titrate in aqueous solution. a)Which solvent,
pyridine or acetic acid, would be more suitable for titration of B with
HClO4? Why? b)Which solvent would be more suitable for the titration of a
very weak acid with tetrabutylammonium hydroxide? Why? (6%)
7. What does a negative pH mean for the strong acid? (8%)
8. Derive equations for αH3A, αH2A-, αHA2-, and αA3- for a triprotic
system. (8%)
9. Explain how isoelectric focusing works.(6%)
10. How to determine the amount of a mixture of boric acid and borax? (8%)
11. Calculate the pI value (isoelectric point) of glycine, NH2CH2COOH.
(Note Ka=2x10^-10; Kb=2x10^-12) (7%)
12. Describe the operations you would perform to prepare exactly 100mL of
0.200M acetate buffer, pH 5.00, starting with pure liquid acetic acid and
solutions containing ~3M HCl and ~3M NaOH. (pKa=4.75 for acetic acid)
13. pH is one of the most important controlling factors in the rats and
thermodynamics of every biological process. Could you give a method for
measuring pH inside embryos and even single cells? (10%)
14. In contrast to many salts, calcium sulfate is only partially dissociated in
aqueous solution: CaSO4(aq)<=>Ca2+ + SO42- Kd=5.2x10^-3
The solubility product constant for CaSO4 is 2.4x10^-5. Calculate the
solubility of CaSO4 in (a)water and (b) 0.0100M Na2SO4. (10%)
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