→ whaleswin16 :已收農化系精華區 01/14 16:54
課程名稱︰物理化學上
課程性質︰必修
課程教師︰陳振中
開課學院：
開課系所︰農化系
考試日期（年月日）︰ 2011.01.13
考試時限（分鐘）： 110 mins
是否需發放獎勵金： 是
（如未明確表示，則不予發放）
試題 :
Section A (80%)
1. (10%)Liquid mercury has a density of 13.7 g/cm3, and solid mercury has
a density of 14.2 g/cm3, both being measured at the melting point, -38.87
℃, at 1 bar pressure. The heat of fusion is 9.75 J/g. Calculate the
melting points of mercury under a pressure of (a)10 bar and (b)2540bar.
2. (12%)Ethanol and methanol form very nearly ideal solutions. At 20℃, the
vapor pressure of ethanol is 5.93 kPa, and that of methanol is 11.83 kPa.
(a)Calculate the mole fractions of ethanol and methanol in a solution
obtained by mixing 120 g of each. (b) Calculate the total vapor pressure
of the solution. (c) Calculate the mole fraction of ethanol in the vapor.
3. (12%)The solubility of Ag2CrO4 in water is 8.00*10^-5 mol/kg at 25℃,
and its solubility in 0.04 mol/kg NaNO3 is 8.84*10^-5 mol/kg. What is
the mean ionic activity coefficient of Ag2CrO4 in 0.04 mol/kg NaNO3?
4. (10%)Calculate ΔmixG and ΔmixS for the formation of a quantity of air
containing 2 mol of gas by mixing nitrogen and oxygen at 350 K. Air may
be taken to be 80% nitrogen and 20% oxygen.
5. (10%)Calculate the extent of reaction α of 1 mol o H2O(g) to form H2(g)
and O2(g) at 2000 K and 1 bar. (Since the extent of reaction is small,
the calculation may be simplified by assuming that PH2O = 1bar.)
1
H O (g) → H (g) + — O (g)
2 ← 2 2 2
6. (16%)The NBS tables contain the following data at 298 K:
ΔrH。/ kJ/mol ΔrG。/ kJ/mol
CuSO4(s) -771.36 -661.8
CuSO4．H2O(s) -1085.83 -918.11
CuSO4．3H2O(s) -1684.31 -1399.96
H2O(g) -241.818 -228.572
(a)What is the equilibrium constant over a mixture of CuSO4(s) and
CuSO4．H2O(s) at 298 K?
(b)What is the equilibrium constant over a mixture of CuSO4(s) and
CuSO4．3H2O(s) at 298 K?
(c)What is the answer to (a) if the temperature is 596 K and ΔCp。
is assumed to be zero?
7. (10%)Calculate the molar Gibbs energy G of fusion when supercooled water
at -10℃ freezes at constant T and P. The enthalpy of fusion of ice is
6000 J/mol at 0℃. The heat capacities of water and ice in the vicinity
of freezing point are 75.3 and 38 J/ K mol, respectively.
Section B (20%)
1. (10%)Consider a mixture of two liquids, A and B. The following diagram
shows the experimental partial pressure of A and B, denoted as PA and
PB, respectively.
圖略
(a) Compare the intermolecular interaction of A-B with that of A-A or
B-B. Explain why.
(b) On the basis of the figure, estimate the activity coefficients of
B at xB = 0.5. Provide your answer to the nearest digit. For example,
the PA value at xB = 0 can be estimated as 82 Pa and the PB value at
xB = 1 be 36 Pa.[Hints: The Henry's constant of B is 78 Pa]
2. (10%)The following diagram shows a typical PV diagram taken from the
textbook (Fig.3.14): 圖略
The curve from A to B corresponds to isothermal expansion at temperature
T1 and that from C to D corresponds to isothermal compression at temperature
T2.The two curves from B to C and from D to A are adiabatic processes.
(a) Is it possible to have two adiabatic processes cross at a particular
state as shown below ? Justify your statement.[Hint:Design a cyclic
process and consider the change of a state function]圖略
(b) Consider an adiabatic process which starts and ends at two different
temperatures. Can the process start or end at 0 K ?
________
CdT
dS = ——
T
ΔG。 = ΔH。- TΔS。
_
dP ΔH
—— = ——_
dT TΔV
ν±
a = (γ m )
Aν+Bν- ±±
log γ = Az z √I (A = 0.509 kg^1/2 mol^1/2 for aqueous solution at 298.15 K
± + -
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