Untitled - Kelly Walsh High School

94 CHEMISTRY FOR THE UTTERLY CONFUSED
theory and investigated certain equations describing the properties of real
gases. You learned that you could use the van der Waals equation in those cases
where there was significant deviation from ideal gas behavior. And finally, you
hopefully learned that in order to learn to work gas law problems it will take
Practice, Practice, Practice.
1. Write the expression for Dalton’s law.
2. Write the expression for the combined gas equation.
3. Write the expression for the ideal gas equation.
4. List the pressure units introduced in this chapter, and show the relationships
between these units.
5. Write the rearranged expression of the ideal gas equation where you are
solving for moles.
6. Write the rearranged expression of the combined gas equation where you
are solving for T 2.
7. Fill in the blank in each of the columns below with either I (increases), or D
(decreases), or C (constant). The potential changes apply to a sample of gas:
a. b. c. d. e.
Volume constant ___ constant constant increases
Pressure increases constant increases ___ ___
Temperature constant decreases ___ increases constant
Moles ___ constant constant constant constant
8. A sample of a gas occupies 15.55 L at a temperature of 27C. What temperature,
in C, is necessary to adjust the volume of the gas to 10.00 L?
9. The initial pressure on a sample of oxygen gas was 795.0 torr. At this pressure,
the sample occupied 1250.0 mL at 0C. What was the final pressure, in
atm, of this sample of oxygen gas if the final volume was 1.000 L and the
final temperature was 25C?
10. A sample of xenon gas was collected in a 5.000 L container at a pressure of
225.0 mmHg, and a temperature of 27.0C. Later the pressure had changed
to 1.000 atm, and the temperature was 0.0C. What was the new volume, in
liters, of the gas?
11. The molecular weight of an unknown gas was to be determined through an
effusion experiment. The unknown gas effused at a rate of 0.1516 mL/s. Under
the same conditions, a sample of oxygen effused at a rate of 0.3238 mL/s.
Determine the molecular weight of the unknown gas.
12. The decomposition of NaN3 will generate N2 gas. A 8.25 L sample of gas was
collected over water at 25C and at a total pressure of 875 torr. How many
grams of NaN3 reacted? The vapor pressure of water, at 25C, is 24 torr.
2 NaN3(s) l 2 Na(s) 3 N2(g)