Chemistry 132 (Exam II Review)
Useful Constants, Equations, Conversions:
1 ft. = 12 in.
5280 ft= 1 mile
1 in.= 2.54 cm
1 mL=1 cm3
me=9.1093819×10-31kg
Avogadro’s number=6.022141×1023mol-1
1609.3 m= 1 mile
1 kg= 2.2046 lb
=𝑚𝑣
1 lb= 16 oz.
1 gallon= 3.785 L
ℎ
Answer
1. The magnitude of the heats of vaporization, fusion and sublimation of a
substance reflect the
a. Density of a substance
b. Magnitudes of the boiling and melting points of the substance
c. Strength of the covalent bonds between atoms in each molecule of the
substance
d. Strength of the intermolecular forces of the substance
2. Which of the following is NOT an assumption of the kinetic molecular
theory of gases?
a. All gas particles move at the same speed
b. A gas is mainly empty space
c. Gas particles move in random directions
d. There are no forces between gas particles
3. Liquids will boil at lower temperatures at higher elevations because…
a. The intermolecular forces are weaker
b. The vapor pressure at which boiling occurs is lower
c. It is harder to transfer heat to the liquid
d. Atmospheric pressure increases
4. In Van der Waals equation, the constant b is a factor that corrects for…
a. Derivations in the gas constant R
b. The attractive forces between gas particles
c. The average speeds of the gas particles
d. The volume occupied by the gas particles
5. Which of the following is an example of a colligative property?
a. Ethanol mixes with water, but vegetable oil does not
b. Pure water freezes at 0oC, but salt water does not
c. Fluorine is a gas at room temperature, but iodine is a solid
d. Sugar is easier to dissolve in hot coffee than iced coffee
6. Which of the following boils at the lowest temperature?
a. KNO3
b. Ca
c. Kr
d. NH3
7. A liquid’s resistance to flow is referred to as…
a. Surface tension
b. Capillary action
c. Viscosity
d. Vapor Pressure
8. How can we increase the solubility of carbon dioxide in water?
a. Heat the water to a higher temperature
b. Heat the carbon dioxide to a higher temperature
c. Increase the total pressure over the water while keeping the
number of moles of carbon dioxide constant
d. Increase the number of moles of carbon dioxide over the water
while keeping the total pressure constant
9. Which of the following interactions are the strongest?
a. Hydrogen bonding interactions
b. Ion-ion interactions
c. Dipole-dipole interactions
d. London dispersion forces
10. A mixture pf helium and sulfur hexafluoride effuses through a small hole.
What can be said about the relative rates of effusion for these gases?
a. Helium effuses about 36 times faster than sulfur hexafluoride
b. Helium effuses about 6 times faster than sulfur hexafluoride
c. Sulfur hexafluoride effuses about 36 times faster than helium
d. Sulfur hexafluoride effuses about 6 times faster than helium
11. Which factors influence the vapor pressure of a compound (Circle all that
apply)?
a. Total Pressure
b. Temperature
c. Intermolecular forces
d. Volume
12. Which packing system has the least empty space?
a. Simple cubic
b. Face centered cubic
c. Body Centered Cubic
d. Lateral centered cubic
13. The sum of Hfusion and Hvaporization for a compound (at constant P, T) is
always equal to the
a. Heat of sublimation
b. Heat of Deposition
c. Heat of Condensation
d. Heat of vaporization
14. Kinetic molecular theory
A gas consists of tiny particles moving in constant,
motion. The
of the gas particles themselves is negligible when compare to the space that they occupy.
Particles act independently of each other. There are no
or
forces between particles. Collisions between gas particles and other particles/walls of the
container are perfectly
, there is no net energy loss from collisions. The
collisions with the walls of the container give rise to the
of the gas. The
is a measure of the average kinetic energy of a gaseous sample.
15. Refer to the van der Waals equation of state to answer the following questions about the
parameters ‘a’ and ‘b’
Put the following molecules in order of their increasing ‘b’ values: Ar, Ne, He, and Kr
16. Using the physical meaning of ‘a’, offer a reasonable explanation for why ammonia
(NH3) has a larger a value than neon does
17. Rank the following substances in order of increasing boiling point: ethylene glycol
(HOCH2CH2OH), ethanol (CH3CH2OH), glycerol (HO-CH2-CHOH-CH2-OH). Explain.
18. The enthalpy of vaporization of water is -40.67 kJ/mol, the enthalpy of fusion for water is
-6.01 kJ/mol, the molar heat capacity of liquid water is 75.4 J/(moloC), and the molar
heat capacity of ice is 36.4 J/(moloC)
a. How much heat is released when 75.0 g of steam at 100.0 oC is cooled to ice at -15.0oC?
19. An unknown gas effuses 1.73 times faster than krypton. What is the molar mass of the
gas?
20. A 1.30 M solution of CaCl2 (MM=111.0 g/mol) in water has a density of 1.11 g/mL.
What is the molality of CaCl2?
21. A solution of LiCl in water is 18.0 mass % LiCl. What is the mole fraction of LiCl?
22. A kitchen pressure cooker operates at 1.50 atm, The Hvap of water is 40.7 kJ/mol. What
is the boiling point of water in the pressure cooker?
23. An element forms a body centered cubic crystalline substance. The edge length of the
unit cell is 287 pm and density of the crystal is 7.92 g/cm3. Determine the identity of the
substance.
24. Cesium metal is frequently used in photoelectric cells because the amount of energy
necessary to eject electrons from a cesium surface is relatively small, only 206.5 kJ/mol.
What wavelength of light does this correspond to? What type of light does this
correspond to (Infrared, Visible, UV, etc.)?
25. Given that the density of iron is 7.87 g/cm3, and the natural abundance of 54Fe is 5.80%,
calculate the number of 54Fe atoms in a 1.00 ft3 block of Fe.
26. The average atomic mass for Ne is 20.1797 amu. Use this to complete the table below.
Please report the mass of the unknown isotope to three significant figures.
Isotope
20
Ne
21
Ne
Mass (amu)
19.992440
20.993847
Natural Abundance
90.48%
9.25%
27. Recently, California has been experiencing the worst drought in its history. Let’s say that
a typical rain guage is rectangular in shape with the dimensions 1.0 in (width) × 1.0 in
(length) × 10.0 in (height). What is the mass (in grams) of rainwater present in the gauge
if the height of the water column is 2.5 in? Assume the density of rainwater to be 1.00
g/cm3.
28. The metal tungsten has a threshold energy of 7.29×10-19J. When a particular light source
is used, the maximum kinetic energy of an electron ejected from the surface of tungsten is
1.92×10-19J. Given this information, what wavelength of light is emitted by this light
source?
29.
a.) A jeweler bought a diamond at wholesale price, paying $8,535 for a 651mg diamond.
How much did the jeweler pay per carat? There are exactly 0.2 grams per carat.
b.) Diamond is made entirely of carbon atoms. How many carbon atoms did she
purchase?
30. When ultraviolet light of a certain frequency shine son a zinc surface, an electron is
ejected with a kinetic energy of 5.55×10-18J. What is the de Broglie wavelength of the
ejected electron?
31. Silicon has three naturally occurring isotopes: 28Si (27.976928 amu), 29Si (28.976496 amu),
and 30Si. If the relative abundances of 28Si and 29Si are 92.23% and 4.67%, respectively, what
is the atomic mass of 30Si? Give your answer to four significant figures.