课程名称：普通化学乙上
课程性质︰必修
课程教师︰林英智
开课学院：生农学院
开课系所︰森林环资系
考试日期（年月日）︰2014/01/08
考试时限（分钟）：110分钟
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
Avogadro's number NA=6.02x10^23
Gas constant R=0.0821 Latm/molK = 8.31 J/molK
1. Chromium crystallizes with a body-centered cubic unit cell. The radius
of a chromium atom is 125 pm. Calculate the density of solid crystalline
chromium in g/cm3 . Atomic weight Cr 52.0.
2. Methanol has a normal boiling point of 64.6°C and a heat of vaporization of
vaporation (△Hvap) of 35.2 KJ/mol. What is the vapor pressure of methanol at
45°C.
3. Draw the shape of all eight molecular orbitals from linear combination of
one 2s and three 2p atmoic orbitals for homodiatomic molecule.
4. Draw two energy level diagrams of the molecular orbital of 2s and 2p for B2
and O2. Explain why both of them are paramagnetic. Find the bond order of
B2, B2+ and O2,O2+.
5. Using VSEPR to predict the structure of the following molecules: SF4, BrF3,
BrF5, XeF2, XeF4.
6. Three 1.0 flasks, at 308K, are connected to each other with stopcocks. One
of the flasks contains 1.0 atm of N2, the second 0.10g of H2O; the third 0.40g
of ethanol C2H5OH when the stopcocks are closed. The vapor pressure of H2O is
42 mm-Hg and that of ethanol is 102 mm-Hg at 308K. What is the pressure when
the stopcocks are opened and the contents mix greely?
7. Draw the structures of two compounds that have the composition CH3NO2 and
have all three H atoms bonded to the C. Predict which compound has the larger
ONO bond angle.
8.
(a) Make sketch of three resonances forms for methylazide(CH3N3).
(b) Use VSEPR to predict the geometry and formal charge of three nitrogen atoms.
(c) Compare the bond angles of interior nitrogen toms and two nitrogen-nitrogen
bond lengths.
9. Tetrahedral hole is formed when four spheres of radius r are in contact and
plsced at alternate corners of a cube. The hole is inside the middle of the
cube. Find the length of the body diagonal of this cube and the radius of the
tetrahedral hole.
10. Butane(C4H10) has a heat of vaporization of 22.44 KJ/mol and a normal
boiling point of -0.4°C. A 150 mL sealed flask contains 0.40g of butane at
-20°C. How much butane is present as a liquid? If the butane is warmed to
20°C, how much is present as a liquid and find the final pressure?