課程名稱︰普通化學
課程性質︰系上必修
課程教師︰林英智
開課學院：醫學院
開課系所︰藥學系,醫技系
考試日期（年月日）︰2006-12-15
考試時限（分鐘）：10:20~12:10
是否需發放獎勵金：是,謝謝
（如未明確表示，則不予發放）
試題 :
General Chemistry - Mid Term 2 (2006)
1. For the oxidation-reduction:
(S4O6)2- (aq) + Cr2+ (aq) --> Cr3+ (aq) + (S2O3)2- (aq)
the appropriate half-reactions are:
(1) (S4O6)2- + 2e --> 2(S2O3)2- E°= +0.17 V
(2) Cr3+ + e --> Cr2+ E°= -0.50 V
Balance the redox reaction and calculate E° (3%) and K at 25℃ (4%).
2. Consider the following galvanic cell:
Pb ∣ Pb2+ (1.8M) ∣---0.83V---∣ Ag+ (?M) , (SO4)2- (?M) ∣ Ag
Ag+ + e --> Ag E°= +0.80 V
Pb2+ + 2e --> Pb E°= -0.13 V
Calculate the Ksp value for Ag2SO4(s). Note that to obtain silver ions in
the right compartment (the cathode compartment), excess solid Ag2SO4 was
added and some of the salt dissolved. (7%)
3. A zinc-copper battery is constructed as follows:
Zn ∣ Zn2+ (0.1M) ∣∣ Cu2+ (2.50M)∣ Cu
Cu2+ + 2e --> Cu E°= +0.34 V
Zn2+ + 2e --> Zn E°= -0.76 V
The mass of each electrode is 200g.
(a) Calculate the cell potential when this battery is first connected. (3%)
(b) Calculate the cell potential after 10.0A of current has flowed for
10.0h. (Assume each half-cell contains 1.00L of solution.) (3%)
(c) Calculate the mass of each electrode after 10.0h. (3%)
(d) How long can this battery deliver a current of 10.0A before it goes
dead? (4%)
4. Calculate the energy required to excite the hydrogen electron from level
n = 1 to n = 2. Also, calculate the wavelength of light that must be
absorbed by a hydrogen atom in its ground state to reach this excited
state. (R(H) constant: 2.178x10^-18 J) (5%)
5. In ground state of cadmium (Cd),
(a) How many electrons have ι = 2 as one of their quantum numbers? (2%)
(b) How many electrons have n = 4 as one of their quantum numbers? (2%)
(c) How many electrons have mι = -1 as one of their quantum numbers? (2%)
6. The treatment of a particle in a one_dimensional box can be extended to a
two-dimensional box of dimensions Lx and Ly yielding the following
expression for energy:
E = h^2/8m [ (nx/Lx)^2 + (ny/Ly)^2 ]
h = 6.626x10^-34 Js
mass of e = 9.11x10^-31 kg
nx, ny: the quantum numbers of x and y
The two quantum numbers independently can assume only integer values.
Consider an electron confined to a two-dimensional box that is 8.00 nm in
the x direction and 5.00 nm in the y direction.
(a) What are the quantum numbers for the first three allowed energy
levels? (3%)
(b) Calculate the wavelength of light necessary to promote an electron from
the first excited state to the second excited state. (5%)
7. The microwave spectrum of 1H79Br (HBr) shows that the transition from J = 0
to J = 1 requires electromagnetic radiation with a wavelength of 587μm.
Calculate the bond length of the 1H79Br molecule. (7%)
(The masses of 1H and 79Br are 1.0078 amu and 78.9183 amu, respectively.)
8. Write the Lewis structure and molecular structure for each molecule or ion.
(a) ClF3
(b) XeO3
(c) RnCl2
(d) BeCl2
(e) (ICl4)- (total: 20%)
9. Nitrous oxide (N2O) has three possible Lewis structures:
‥ ‥ ‥ ‥
Ｎ = Ｎ = Ｏ <---> :N≡Ｎ－Ｏ: <---> :Ｎ－N≡O:
‥ ‥ ‥ ‥
( <---> refers to resonance. )
(a) Given the following bond lengths, rationalize the observations that
N-N bond length in N2O is 0.112 nm and that the N-O bond length is
0.119 nm. (3%)
Ｎ－Ｎ 0.167 nm
Ｎ＝Ｎ 0.120 nm
Ｎ≡Ｎ 0.110 nm
Ｎ＝Ｏ 0.115 nm
Ｎ－Ｏ 0.147 nm
(b) Assign formal charges to the resonance structures for N2O. Can you
eliminate any of the resonance structures on the basis of formal
charge? Is this consistent with observation? (4%)
10. Using the bond energies:
C-H 413 kJ/mol
Cl-Cl 239 kJ/mol
F-F 154 kJ/mol
C-F 485 kJ/mol
C-Cl 339 kJ/mol
H-F 565 kJ/mol
H-Cl 427 kJ/mol
calculate ΔH for the reaction of methane with chlorine and fluorine to
Freon-12, CF2Cl2. (7%)
CH4 (g) + 2Cl2 (g) + 2F2 (g) --> CF2Cl2 (g) + 2HF (g) + 2HCl (g)
11. (a) For the species O2, (O2)+, (O2)-, give the electron configuration and
the bond order for each. Which has the strongest bond? (10%)
(b) Use the MO model to predict the bond order and magnetism of Ne2 and
P2. (4%)
12. For each of the following molecules or ions, describe the molecular
structure and predict the hybridization of each atom.
(a) CO
(b) (BF4)-
(c) XeF2 (total: 9%)
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※ 編輯: ryo2006 來自: 140.112.7.59 (12/15 17:19)