課程名稱︰普通化學丙
課程性質︰必修
課程教師︰周必泰
開課學院：醫學院/電資學院
開課系所︰醫學系/牙醫學系/電機系
考試日期（年月日）︰2018/01/12
考試時限（分鐘）：170
試題 :
General Chemistry (Total Score 220)
Midterm Examination 2017/11/17
1. Questions in midterm exam
1-1. In infrared spectra, the absorption band of C=O is at about 1700 cm^(-1),
but the absorption band of C-H is at about 3000 cm^(-1). Please explain
why the absorption frequency of C-H is higher than C=O but with much
lower bond energy. (10)
1-2. Thermal energy could be in a form of kT where k is the Boltzmann's
constant (1.38 × 10^(-23) JK^(-1)), T is in Kelvin (K). Please convert
temperature 1K (or 1℃) thermal energy in terms of kcal/mol (5). 298 K is
generally considered to be room temperature. Calculate the associated
thermal energy. (5)
1-3. (a) Draw MOs of B2 and O2 and Explain why both B2 and O2 are paramagnetic
(10). (b) Arrange the ionization energy of O2, O2-, O2+ by increasing
trend (5) (c) A Lewis structure obeying the octet rule can be drawn for O2
as follows:
.. ..
Ｏ＝Ｏ
.. ..
Use the molecular orbital energy-level diagram for O2 to show that the
above Lewis structure corresponds to an excited state. (5)
2. Definition and Explanation (after midterm exam)
2-1. Define superfluid (5), and write down any applications of CO2 and H2O
superfluid (5)
2-2. In the phase diagram for water (see below), explain why the slope of point
C to O line between solid phase and liquid phase is negative, whereas most
of other materials are positive? (5) Define physical meaning of point O
and point A (5).
https://i.imgur.com/VXlRqaL.png
2-3. Using the band gap theory to explain the_conductor, semiconductor and
insulator (10). Upon increasing temperature, predict the changes of the
conductivity for these three types of materials and explain (5).
2-4. Define p type and n type semiconductors (5). Put materials Ga As and
0.6 0.4
Ga As together, please specify which is p and which is n type (5).
0.4 0.6
Briefly describe p-n junction and its application in light emitting diode
(5) or rectifier (5). Define Fermi energy level (5).
2-5. Define (a) steady-state approach (5) (b) elementary step (5)
(c) molecularity (5) (d) the difference between half-life and lifetime (5)
2-6. The Arrhenius equation for the reaction rate can be generally expressed as
-Ea/RT -Ea/RT
k = zpe . Please explain the definition of z,p and e (5). Which
-Ea/RT
parameter z,p or e is changing when the catalyst is added? (5)
2-7. The graph below shows the number of collisions with a particular energy
for two different temperatures.
https://i.imgur.com/IvfD5Qi.png
a. Which is greater, T2 or T1? How can you tell? (5)
b. What does this graph tell us about the temperature dependence of the
rate of a chemical reaction? Explain. (5)
3. Question
3-1. The standard enthalpy of formation of H2O(l) at 298K is -285.8kJ/mol.
Calculate the change in internal energy for the following process at 298K
and 1 atm: (10)
H2O(l) → H2(g) + 1/2 O2(g)
3-2. An isothermal process is one in which the temperature of the system and
surroundings remain constant at all times. With this mind, what is wrong
with the following statement : "for an isothermal expansion of an ideal
gas against a constant pressure, ΔT = 0, so q = 0" ? What is q equal to
in an isothermal expansion of an ideal gas against a constant external
pressure? (10)
3-3. Cubic packing spheres are stacked on top of each other in successive
layers.
Define
volume occupied by spheres in the unit cell
f_v = ───────────────────────
volume of the unit cell
prove f_v = 52.4% for a cubic packing (10).
3-4. Considering two Bricks with two different temperatures and different molar
heat capacity (Cp) shown below:
┌────╥────┐
│ ║ │
│ Cp1,T1 ║ Cp2,T2 │
│ ║ │
└────╨────┘
Assuming T1 > T2, based on the second law of thermodynamics to predict the
direction of the flow of the heat when two bricks are contacted. Assuming
Cp1 and Cp2 are both temperature independent, what is the final
temperature after connecting these two bricks? (Assuming one mole for each
brick) (10)
3-5. (a) Write down the definition of thermodynamic parameters G and H . Then,
derive the following relationship (10)
dG = VdP - SdT
dH = TdS + VdP
in which P, V and T denote pressure, volume and temperature,
respectively, and S is system entropy at 25°C
(b) Explain why you need to make diamond from graphite at high pressure
and decent temperature (5)
https://i.imgur.com/RRzAjFV.png
3-6. The reaction between NO and H2 may proceed via the following mechanism
(single answer)
k_-1
1. 2NO ⇋ N2O2
k1
k2
2. N2O2 + H2 → N2O + H2O
Apply the steady-state approximation for N2O2, express the rate of H2
depletion in (a) very low H2 concentration, (b) very high H2 concentration
and (3) medium H2 concentration. (15)
3-7. The van't Hoff equation is expressed as
0
K2 -ΔH 1 1
ln─ = ───(─ - ─)
K1 R T2 T1
0
where K1 and K2 are equilibrium constants at T1 and T2, respectively, ΔH
is the standard enthalpy change of the reaction. Please derive this
0 -6
equation from ΔG (5). Kp is 3.7×10 at 900K for the ammonia synthesis
-3
reaction. Assuming the value of Kp is 8.2×10 at 500K. Calculate the
reaction enthalpy ΔH (5)
◎ 口頭說明 2-4. light emitting diode (發光二極體); rectifier (整流器);
or 的意思是兩者都要回答
◎ 投影補充 3-7. R = 8.314 J K^(-1) mol^(-1)