CHM 2045C Module 6 Sample Exam
Part M: Multiple Choice Sample Answers
1. The
correct answer is:
710 torr
Explanation:
Patm = PT - h = 760 torr -
50 torr
Solution Reference:
Page 539, Gas Pressure
2. The
correct answer is:
Charles
Explanation:
V = kT
Solution Reference:
Page 545, Charles's Law
3. The
correct answer is:
P, V
Explanation:
Solution Reference:
Page 548, The General Gas Law
4.
The
correct answer is:
Explanation:
VN = VO x pressure
factor x temperature factor. Why is the pressure factor less than one? Why is
the temperature factor greater than one?
Solution Reference:
Page 548, The General Gas Law
5. The
correct answer is:
Explanation:
V = 75 mL x
temperature factor x pressure factor. The temperature factor should be less
than one. Why? The pressure factor should be greater than one. Why?
Solution Reference:
Page 548, The General Gas Law
6. The
correct answer is:
The pressure will increase by a factor
less than five.
Explanation:
Remember to convert the temperatures to the
Kelvin scale. PN =
Solution Reference:
Page 548, The General Gas Law
7. The
correct answer is:
18 x 22.4 L
Explanation:
Solution Reference:
Page 555, Gas Laws and Chemical Reactions
8. The
correct answer is:
55.6 g/mol.
Explanation:
One mole = one gram molecular mass = 22.4 L at
STP:
or use a derivation of PV = nRT.
Solution Reference:
Page 552, Density of Gases
9. The
correct answer is:
C3H8.
Explanation:
Solution Reference:
Page 552, The Density of Gases
10. The
correct answer is:
NF3
Explanation:
Solution Reference:
Page 552, Gas Densities
11. The
correct answer is:
0.010
Explanation:
Use the equation PV = nRT.
It doesn't matter what the gas molecules are.
Solution Reference:
Page 558, Gas Mixtures and Partial Pressures
12. The
correct answer is:
0.040 moles
Explanation:
Solution Reference:
Page 558, Gas Mixtures
13. The
correct answer is:
1.00 L of CO at 0.0?C and 1.25 atm
Explanation:
Look for a low temperature and a high pressure
combination. Why?
Solution Reference:
Page 550, The Ideal Gas Law
14. The
correct answer is:
The volume of the sample would be zero
at -273?C.
Explanation:
Nitrogen has mass, and even though it will be
frozen at absolute zero, it must of necessity have a volume.
Solution Reference:
Page 562, The Kinetic-Molecular Theory of
Gases
15. The
correct answer is:
is decreased by decreasing the kinetic
energy of the gas molecules.
Explanation:
It only has a value of 22.4 L at 273 K and 1 atm pressure. The volume decreases with a decrease in
temperature.
Solution Reference:
Page 562, Kinetic-Molecular Theory of Gases
16. The
correct answer is:
1 : 1.
Explanation:
This question is testing a student's knowledge
of Avogadro's law. At the same temperature and pressure, equal volumes of all
gases contain the same number of molecules.
Solution Reference:
Page 562, The Kinetic-Molecular Theory of
Gases
17. The
correct answer is:
kinetic energy.
Explanation:
The kinetic energy of a gas depends upon
temperature. At the same temperature, all gases have the same average kinetic
energy.
Solution Reference:
Page 562, The Kinetic-Molecular Theory of
Gases
18. The
correct answer is:
when the temperature is increased and
the pressure is decreased.
Explanation:
Most real gases approach ideal behavior at
high temperatures and at low concentrations.
Solution Reference:
Page 571, Real Gases
19. The correct answer is:
High temperature and
low pressure
Explanation:
Low concentrations
and high kinetic energies (high temperatures).
Solution Reference:
Page 571, Real Gases
20. The correct answer is:
NH3
Explanation:
NH3 is a
highly polar molecule. The dipole-dipole interaction between NH3
molecules is large enough that it is called hydrogen bonding.
Solution Reference:
Page 571, Nonideal Behavior
21. The
correct answer is:
1 : 2.
Explanation:
Solution Reference:
Page 568, Diffusion and Effusion
22. The
correct answer is:
1 to 1.
Explanation:
K.E. = 1/2 mv2. The kinetic energy
changes with (and is proportional to) the absolute temperature.
Solution Reference:
Page 562, Kinetic-Molecular Theory of Gases
23. The
correct answer is:
161/2 to 321/2.
Explanation:
Remember the inverse relationship.
Solution Reference:
Page 568, Diffusion and Effusion
24. The
correct answer is:
Ar
Explanation:
All of the molecules have molecular masses
less than that of "air" except Ar.
Solution Reference:
Page 570, Rubber Balloons
25. The
correct answer is:
24 sec.
Explanation:
This effusion experiment involves time, not
rate.
Solution Reference:
Page
568, Diffusion and Effusion