課程名稱︰物理化學上
課程性質︰農化系大二必修
課程教師︰蘇志明
開課學院：生物資源暨農學院
開課系所︰農業化學系 (化學系開課)
考試日期（年月日）︰2008年12月04日
考試時限（分鐘）：110 mins
是否需發放獎勵金：YES!!
（如未明確表示，則不予發放）
試題 :
1. The shells of marine organisms contain CaCO3 largely in the crystalline
form known as calcite. There is a second crystalline form of CaCO3 known
as aragonite.
(a) Based on the thermodynamic and physical properties given in the following
table for these two crystalline forms, would you expect calcite in nature
to convert spontaneously to aragonite given sufficient time? Justify your
answer.
(b) Will the conversion proposed in part (a) be favored or opposed by increa-
sing the pressure? Explain.
(c) What pressure should be just sufficient to make this conversion spontaneous
at 25℃?
(d) Will increasing the temperature favor the conversion? Explain.
┌───────────┬──────────┬──────────┐
│ Properties at 298K │ CaCO3 (calcite) │ CaCO3 (aragonite) │
├───────────┼──────────┼──────────┤
│ ΔH(kJ/mol) │ -1206.87 │ -1207.04 │
│ ΔG(kJ/mol) │ -1128.76 │ -1127.71 │
│ S(J/K*mol) │ 92.88 │ 88.70 │
│ Cp(J/K*mol) │ 81.88 │ 81.25 │
│ density(g/cm^3) │ 2.710 │ 2.930 │
└───────────┴──────────┴──────────┘
2. At 25℃ the carbon dioxide gas follows the van der Waals equation with the
van der Walls constants a= 3.6L^2*atm/mol^2 and b= 0.043L/mol. Calculate
the work, heat, internal energychange, and enthalpy change if the gas is
expanded reversibly and isothermally form an initial volume of 5L to final
volume of 10L. We know the following relations:
ａ
(Ⅰ) van der Waals equation: ( Ｐ＋ ── )(Ｖ－ｂ)＝ＲＴ
Ｖ^2
δＰ
(Ⅱ) The internal energy: dＥ＝Ｃv dＴ ＋ [Ｔ(──)v－Ｐ] dＶ
δＴ
(Ⅲ) 1 L*atm＝24.2 cal; 1 cal＝4.18 J; R＝0.082 L*atm/℃*mol＝8.31 J/K*mol
3. Calculate the activity α(H2O) of liquid water at 293K and a pressure of
(a) 10atm and (b) 1000atm. The empirical molar volume of the liquid water
is: __
Ｖwater＝18.07 (1－45.9 ×10^-6Ｐ) mL/mol (Ｐ in atm)
4. The free energy of the hydrolysis of ATP at biochemist's standard state
25℃ is: o,
ATP ＋ H2O ─→ ADP ＋ Pi (ΔＧ ＝ -31.0 kJ/mol)
(a) Calculate the ΔＧ for the reaction when [ATP]＝10^-2 M, [ADP]＝10^-4 M,
and [phosphate]＝10^-1 M.
(b) Calculate the maximum available work under the conditions of part (a)
when 1 mole of ATP is hydrolyzed. This work can be used, for example, to
contract a muscle and raise a weight.
(c) Calculate ΔＧ and the maximum available work if [ATP]＝10^-7 M,
[ADP]＝10^-1 M, and [phosphate]＝2.5*10^-1 M.
5. Without referring to the thermodynamic equations, qualitatively describe
the origin of the Donnan effect and Donnan potential (i.e. give a physical
picture of this effect).
6. In living biological cells, the concentration of sodium ions inside the
cell is kept at a lower concentration than the concentration outside the
cell.
(a) Consider the following process at 37℃ and 1 atm.
1 mol NaCl (0.05 M inside) ─→ 1 mol NaCl (0.02 M outside)
Write an expression for the free energy change for this process in terms
of activities.
(b) Calculate Δμ for the process. You may assume that the activity coeffi-
cient is 1. Will the process proceed spontaneously?
(c) Calculate ΔＧ for moving 3 mol of NaCl from inside to outside under
these conditions.
(d) Calculate Δμ for the process if the activity of NaCl inside is equal
to that outside.
(e) For a cell without any ion channels, a membrane potential could be set
up under the conditions described in part (a). Calculate Δμ for the
process of (a) under a membrane potential Ｖ.
(f) From part (e), what would be the equilibrium potential across the cell
membrane if the inside and outside NaCl concentrations were kept un-
charged as in part (a).
-----------------------------------------------------------------------------
Some equations:
o
dＧ＝ＶdＰ－ＳdＴ μ＝μ ＋ ＲＴlnａ
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※ 編輯: whaleswin16 來自: 61.231.150.65 (02/08 14:16)