Wrap-Up

In this lesson we've looked at the behavior of ideal gases and the conditions under which real gases behave ideally.

The kinetic molecular theory describes gases in terms of the behavior of the gas particles which make them up. It predicts specific relationships between pressure, temperature, volume and the number of moles of gas present, relationships that are summarized in the Ideal Gas Law (which is a combination of Boyle's Law, Charles' Law, and Avogadro's Law) and Dalton's Law of Partial Pressures. We also learned how to relate the density of an ideal gas to its molecular weight.

To complete this lesson, you should try the self quiz. You can check your answers below. Remember that you will get the most benefit from the Self Quiz if you treat it as a "real" quiz; put away your notes and workbook, use the calculator that you will use on the "real" quiz, and see how you do. If you can't answer a question without checking your notes, then that is material that you should study more before you are finished with the lesson.

Of course, if you have questions about any of the material in this lesson, contact your instructor or get help in the lab.

Self Quiz

Circle the letter of the best answer for each of the questions below.

1. "The volume and pressure of a gas sample are inversely proportional if the temperature is held constant" is a statement of:

a. Avogadro's Law.

b. Boyle's Law.

c. Charles' Law

d. Dalton's Law.

e. Ideal Gas Law.

2. The molecules of ideal gases are said to have:

a. strong forces of attraction and no volume.

b. strong forces of attraction and some volume.

c. weak forces of attraction and no volume.

d. weak forces of attraction and some volume.

e. no forces of attraction and no volume.

3. 380 mm of mercury is how many atmospheres?

a. .5 b. 1 c. 380 d. 760 e. 22.4

4. What is the molecular weight of a gas which has a density of 2.60 g/L at STP?

a. 8.62 g/mole

b. 11.6 g/mole

c. 19.8 g/mole

d. 25.0 g/mole

e. 58.2 g/mole

5. The volume of a gas will most certainly increase under which of the following conditions?

a. pressure and temperature are increased.

b. pressure and temperature are decreased.

c. pressure is decreased and temperature is increased.

d. pressure is increased and temperature is decreased.

Answer the following questions in the space provided.

6. Calculate the pressure of 5.0 moles of gas in a 5.0 liter container at a temperature of 100K.

8.2 atm

7. If a gas occupies a volume of 3.0 liters at 27 C, what volume will it occupy at 127 C?

4.0 L

8. STP stands for a temperature of O ^oC (or 273 K), and a pressure of 1 atm (or 760 torr or 760 mmHg).

9. The value for R is 0.082 L*atm/K*mol.

10. A sample of oxygen is collected over water. The pressure of the sample is 755 torr. Its volume is 45.0 mL. The temperature is 23 C and the vapor pressure of water at that temperature is 21 torr. What is the partial pressure of oxygen in the sample?

734 torr

Self Quiz Answers