課程名稱︰普通化學乙上
課程性質︰系必修
課程教師︰金必耀
開課學院：工學院
開課系所︰土木系
考試時間︰11/17 10:30-12:20
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1. Name the following compounds (in English).10%
(a) NaHCO3
(b) Ag2CrO4
(c) SF2
(d) N2O
(e) Mg(OH)2
2. Write formulas for the following compounds.10%
(a) gallium arsenide
(b) ammonium hydrogen sulfate
(c) silicon tetrachloride
(d) cadmium selenide
(e) hydrobromic acid
3. A compound known to contain only carbon, hydrogen and nitrogen
undergoes combustion to produce CO2, N2 and H2O. When 1.000g of
the unknown compound is combusted, 1.955g of CO2 and 1.400g of H2O
are produced. In a separate experiment, it is determined that 1.000g
of the compound can produce 0.378g NH3. You may assume that all of
the nitrogen in the compound is converted into NH3. 10%
(a) What is the empirical formula of the compound?
(b) The compound exhibits a gas density at STP of 2.009g/L. What is
the molecular weight and the molecular formula of the compound?
4. Spherical water droplets are dispered in argon gas. At 27。c, each
droplet is 1.0 micrometer in diameter and undergoes collisions with
argon. Assume that inter-droplet collisions do not occur. The
root-mean-square speed of these droplets was determined to be 0.50cm/s
at 27。c. The density of a water droplet is 1.0g/cm3.
(a) Calculate the average kinetic energy (mv平方/2) of this droplet at
27。c. The volumn of a sphere is given by (4/3)拍r三方 where r is
the radius.
If the temperature is changed, then droplet size and speed of the droplet
will also change. The average kinetic energy of a droplet between 0。c
and 100。c as a function of temperature is found to be linear. Assume
that it remains linear below 0。c.
At thermal equlibrium, the average kinetic energy is the same irrespective
of particle masses (equipartition theorem). The specific heat capacity,
at constant volumn, of argon (atomic weight, 40) gas is 0.31/Jg‧K.
(b) Calculate Avogadro's number without using the ideal gas law, the
gas constant, Boltzmanns constant.
5. Hydrogen is the most abundant element in the universe constituting about
75% of its elemental mass. The rest is mostly helium with small amounts
of other elements. Hydrogen is not only abundant. It is the building
block of all other elements. Hydrogen is abundant in stars such as the
sun. Thus the Milky Way galaxy, consisting of over 100 billion stars,
is rich in hydrogen. The distance between stars is several light years
on the average. Hydrogen is also the major constituent of the interstellar
space. There are about 100 billion galaxies in the universe. The empty
space between galaxies is vast. Foe example, the Milky Way galaxy is
separated from its nearest neighbor, the Andromeda galaxy, by 2 million
light years. Hydrogen again is the primary constituent of the intergalactic
space even though the number density is much less than in the interstellar
space. The average density of matter in the intergalactic space, where
the current temperature is the cosmic background energy of 2.7K, is
about 1 atom/m三方. 21%
(a) Calculate the average speed,根號 (8RT/拍M), of a hydrogen atom in
the intergalactic space.
(b) Calculate the volumn of a collision cylinder swept out by a hydrogen
atom in one second by multiplying the cross-sectional area, d2, by its
average relative speed where d is the diameter of a hydrogen atom
(1x10負八次方cm). Multiply the average speed by square root of 2
to get the average relative speed. Molecules whose centers are within
the cylinder would undergo collision.
(c) Calculate the number of collisions per second experienced by a htdrogen
atom by multiplying the above volumn by the number density. How
many years does it take for a htdrogen atom to meet another atom
in the intergalactic space?
(d) Calculate the mean free path of hydrogen in the intergalactic space.
入 is the average distance traveled by a particle between collisions.
Hydrogen atoms are relatively aabundant in interstellar regions within
a galaxy, there being about 1 atom per cm三次方. The estimated
temperature is about 40K.
(e) Calculate the average speed of hydrogen atom in the interstellar
space.
(f) Calculate the mean free path of hydrogen in the interstellar space.
(g) What do these results imply regarding the probability of chemical
reactions in space?
6. Real gas:
(a) Why do real gases not always behave ideally? Under what conditions
does a real gas behave most ideally? Why?
(b) Is the correted (ideal) volumn of a real gas greater or less than
the actual volumn of the container? Why?
7. A spherical vessel with a volumn of 1.00 L was evacuated and sealed.
Twenty-four hours later the pressure of air in the vessel was found
to be 2.4x10負六次方 atm. During this 24-h period the vessel had been
surrounded by air at 25。c and 1.00 atm. Assuming that air is 78 mole
percent nitrogen and that the remainder is oxygen, calculate the diameter
of the tiny circular hole in the vessel that allowed the air to leak in.
8. An unknown binary compound containing hydrogen (XHn) has a density as a
gas that is 2.393 times that of oxygen gas under the same conditions.
When 2.23x10負二次方 mol of this compound reacts with excess oxygen gas,
0.803 g of water is produced. Identify the element in this compound. (
show your reasoning and calculation.)
9. Balance the following equation by half-reaction method:
IO3負 (aq) + I負 (aq) ─→I3負 (aq)
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