推 srwff :化學系已收 06/16 15:46
課程名稱︰普通化學丙
課程性質︰大一必修
課程教師︰林雅凡
開課學院：生農學院
開課系所︰生物產業機電工程學系
考試日期（年月日）︰2009/6/16
考試時限（分鐘）：10:20 ~ 12:10
是否需發放獎勵金：Yes
（如未明確表示，則不予發放）
試題 :
1.The enthalpy of vaporization of ethanol is 38.7 KJ/mol at its boilding point,
78℃. Calculate both the value of ΔSsystem and ΔSsurroundings when 1.00 mol
of ethanol is vaporized at 78℃ and 1 atm. (7%)
2.For the following reaction, predict how the value of K changes as the
temperature is increased. Verify your answer. (8%)
556KJ + CaCO3 → CaO(s) + CO2 (g)
3.A buffer solution 0.24M NH3 and 0.2M NH4Cl
(a) Give a proper expression for the reaction quotient which is equal to Kb
in equilibrium. (6%)
(b) If the solution has a pH of 9.43 at 25℃, determine the value of Kb.
Also calculate ΔG° for the recation at 25℃.(10%)
(c) If 0.0050 mol NaOH is added to 0.500L of this solution, what will be the
pH ？ (8%)
4.Indentify the Bronsted-Lowry acid and bases and their conjugates in
(a) H2S + NH3 → NH4+ + HS-
(b) OH- + H2PO4 → H2O + HPO42-
Also predict the reaction tendency. Explain your answer. (12%)
5.The decoposition of di-tert-butyl-peroxide (DTBP) is a first-order reaction
with a half-time of 320 min at 135℃ and 100 min at 145℃. Calculate Ea for
this recation. (8%)
Ｏ
(C4H9)2O2 → 2 ║ + C2H6
╱╲
DTBP H3C CH3
6.In a 10.0-L comtainer at 1000K, 0.250 mol SO2 and 0.200 mol O2 react to form
0.162 mol SO3 at equilimrium.
2SO2(g) + O2(g) → 2SO3(g) ΔH=-198.2 KJ/mol
(a) What is Kc at 1000K for the reason that is shown here? (6%)
(b) If the volume is compressed to 5.0-L, what direction would the recation
proced? Explain. (8%)
(c) In which direction, the change of the entropy is positive? Explain. (5%)
If lowering the temperature, do you think in which direction is
spontaneous? Explain. (7%)
From the viewpoint of Le Chatelier's principle, do you think it is
consistent with your prediction? Explain. (10%)
7.After 2.4 mol KCN was added to the 0.4 mol of aqueous Fe(NO3)2‧6H2O, the
green solution turned immediately to yellow product K4[Fe(CN)6].
(a) Do you think it is a Lewis acid-base reaction? Explain. (If yes, please
also indicate which one is Lewis acid and which one is Lewis base. If no,
define what kind of reaction it is.) (6%)
(b) Can you explain the fact that Fe(NO3)‧6H2O is green while K4[Fe(CN)6] is
yellow based on crystal field theory. (8%)
(c) If applying a magnetic field to the crystal Fe(NO3)‧6H2O and K4[Fe(CN)6]
, do you think they are attracted or silent in this environment?
Interpret your answer. (6%)
8.(A) Show that the equilibrium constant expression for the reaction
H2 + I2 → 2HI is consistent with this proposed two-step mechanism for
the reaction. (10%)
Fast I2 → 2I
Slow H2 + 2I → 2HI
┌──┬───────┬──────────┬─────────────┐
│Bulb│Original mass │Bulb opened after,h │Vol. of 0.0150 M Na2S2O3 │
│ No.│ of HI.g │ │Required for titration,mL │
├──┼───────┼──────────┼─────────────┤
│ １ │ 0.300 │ 2 │ 20.96 │
├──┼───────┼──────────┼─────────────┤
│ ２ │ 0.320 │ 4 │ 27.90 │
├──┼───────┼──────────┼─────────────┤
│ ３ │ 0.315 │ 12 │ 32.31 │
├──┼───────┼──────────┼─────────────┤
│ ４ │ 0.406 │ 20 │ 41.50 │
├──┼───────┼──────────┼─────────────┤
│ ５ │ 0.280 │ 40 │ 28.68 │
└──┴───────┴──────────┴─────────────┘
I2 + 2Na2S2O3 → Na2S2O6 + 2NaI
(B) The data of HI(g) decomposition is given above. HI(g) is introduced into
five indentical 100ml glass blubs, and the five bulbs are maintained at
623K. Each bilb is opened after a period of time and analyzed for I2 by
titration with 0.0150M Na2S2O3.
What is the value of Kp at 623K ? (10%)
9.Indentify the stronger BASE in each pair, and explain your choice: (12%)
A. HS- or HSe- B. ClO4- or CLO2- C. NO3- or HSO4- D. I- or Cl-
10.Five samples are ready to be examined.After doing several simple experiments
, someone records some facts below. He then sent those to be analyzed
further. The given report is shown below. However, except a quick note, the
tags of their orginal information are missing.
┌─────────────────────────────────────┐
│ Experimental Records │
│ │
│1. A,E,D can pass through the 28 μm filter papers totally without │
│ separation │
│ │
│2. A Visible light scattering has been detected as a beam of light passes │
│ through the systems of B,D,C. │
│ │
│3. If pouring some A into D, the final mixture can be separated by passing│
│ through a 28 μm filter paper. │
│ │
│4. B is hard to characterize, so in keep in cold. │
│ │
└─────────────────────────────────────┘
┌─────────────────────────────────────┐
│ Quick Note for Dr.Martin Yang │
│ │
│A. From Jen-Ai Food Ind. Co, Hsin-Chuang City, 2009/05/12 │
│ │
│B. From Yang-Ming Mt. 2009/05/23 │
│ Caution: This sample would damage the respiratory tract │
│ │
│C. From Hsin-Dian River, 2009/05/18 │
│ │
│D. From Da-Yi Semi-Condoctor Ind. Co, Yi-Land Country, date missing │
│ │
│E. Confidentail │
│ │
└─────────────────────────────────────┘
┌─────────────────────────────────────┐
│ Analysis results-Size and Concentration Determination │
│ Operator: Martin Yang │
│ │
│P.S:Labels are unclear.The following order is according to the new numbers│
│ │
│1. Unknown suspension in water, mean size: 107 μm │
│ │
│2. Clay sol, mean size: 0.32 μm │
│ │
│3. Smog a kind of aerosol, mean size: 0.18 μm │
│ │
│4. Aqueous aluminum sulfate, conc.: 0.1M │
│ │
│5. Aqueous glucose, conc.: 0.2M │
│ │
└─────────────────────────────────────┘
(a) Can you match the proper sample in term of the labels of A-E ?
Explain your matching logic. (8%)
(b) Rationalize the fact that D could be separated by filtering while pouring
some A into it. (6%)
(c) After passing through the 28 μm filter paper, the melting points of A,C,
E have been measured. Arrange these substances in the order of highest to
lowest melting temperature and why. (6%)
(d) In samples of A-E, which are colloids? Explain. (5%)
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