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）︰2017/11/17
考試時限（分鐘）：170
試題 :
General Chemistry (Total Score 220)
Midterm Examination 2017/11/17
1. Definition and Explanation (共 100 分)
1-1. Please write the formula and full name of atom
Example: 氧 Answer: O, oxygen
釩, 鉬, 鈷, 氪, 鍶 (10)
Also, write 吸熱 and 放熱 of a reaction in English (5)
1-2. Please covert the full name of atoms to the formula in both Chinese and
English
Example: Sodium Answer: 鈉, Na
Arsenic, Cesium, Manganese, Ruthenium, Indium (10)
1-3. 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)
1-4. (a) Explain noncrossing rule (5) (b) Explain Hess Law (5) (c) Explain the
difference between electronegativity and electron affinity (5).
(d) Explain the rather small dipole moment (0.112) for CO based on
electron negativity and formal charge (5).
1-5. 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)
1-6. (a) Derive the number of vibrational modes of a linear molecule and a
nonlinear molecule. (10) (b) calculate the number of vibrational modes of
the following molecules : CO2, H2O, H2C=CH2, SO3, C6H6. (5)
1-7. For the A4 family, CO2 gas is prevailing species on the earth, however,
SiO2 gas is rarely observed. Explain. (5). (b) Explain why silicon is
easily forming silicon oxide (5).
1-8. Can we excite an electron from 1s to 2s by photon? How about from π to
π* ? Please explain. (10)
2. Questions (共 120 分)
1 Z
2-1. For 1s orbital, ψ = ────｛(───)^(3/2)｝e^(-Zr/a0)
1s √(π) a0
where a0 = 0.529Å , find out the radius for the maximum probability for
Li2+ . (10)
2-2. Nitrous oxide (N2O) has three possible Lewis structures:
.. .. .. ..
Ｎ＝Ｎ＝Ｏ ↔ :Ｎ≡Ｎ－Ｏ: ↔ :Ｎ－Ｎ≡Ｏ:
.. .. .. ..
Given the following general bond-length information
Ｎ－Ｎ 1.67Å Ｎ＝Ｏ 1.15Å
Ｎ＝Ｎ 1.20Å Ｎ－Ｏ 1.47Å
Ｎ≡Ｎ 1.10Å
a. Write down the formal charge for each Lewis structure (5)
b. Rationalize the observations that the N-N bond length in N2O is 1.12Å
and that the N-O bond length is 1.19Å.(5)
2-3. (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) What is the bond order of O2, O2-, O2+ . (5) (d) 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)
2-4. OCN- and CNO- are isomers. Based on the formal charge, write down the most
stable Lewis structure and geometry for OCN- and CNO- (5). Determine and
explain which one (OCN- or CNO-) is a more stable form (5).
2-5. (a) Draw Lewis structure and geometry of XeO3 (5). What type of
hybridization orbital for Xe in XeO3? (5) (b) Draw Lewis structure and
geometry of ICl3 (5) What type of hybridization orbital for I in ICl3?
(5)
2-6. (a) The vibrational potential energy surface is shown as below. Explain
why the potential is anharmonic rather than harmonic ? (5) (b) Why the
energy spacing decreases and becomes continuous after dissociation? (5)
(c) Briefly describe the selection rule of IR (vibration) and microwave
(rotation) absorption. In other words, what kind of properties that
molecule has to have in order to have IR (vibration) or microwave
(rotation) absorption (see page 700 of the textbook)? (10)
https://i.imgur.com/4T8QXgN.png
2-7. In terms of the molecular orbital model, which species in each of
following two pairs will most likely be the one to gain an electron?
Explain.
(a) CN or NO (b) O2(2+) or N2(2+) (10)
1
2-8. (a) Write the full name of H NMR (5) (b) Which of the following
compounds matches the NMR spectrum shown below? (5) (c) Please assign the
1
H NMR peaks to the corresponding proton. (5)
https://i.imgur.com/G4B0ORo.png
A https://i.imgur.com/eiMr5Ha.png
B https://i.imgur.com/SIMqtGm.png
C https://i.imgur.com/v0KobfG.png
D https://i.imgur.com/nXox9GE.png