Introduction

Gases are characterized by molecules (or atoms) that are very far apart compared to their size. As a result, gases are mostly empty space. They have very low density and are easily compressible. The gas particles move at very high speeds, colliding with each other and with the walls of their container. They therefore have no fixed volume and no characteristic shape of their own. They naturally expand to fill whatever container they are in and, if the container is not sealed, will easily escape.

The physical properties of gases are largely specified by the amount of gas present, their pressure, and temperature.

The purpose of this lesson is to qualitatively and quantitatively describe the behavior of gases.

OBJECTIVES: You have completed this lesson when you can:

1. Describe gases using the kinetic molecular theory.

2. Describe real gases and ideal gases. Explain how real gases differ from ideal gases.

3. Explain what causes pressure and describe how it is measured.

4. Convert among these gas pressure units: mm Hg, torr, atmosphere.

5. Describe how the pressure of a gas sample depends on the volume, temperature, and number of moles of gas in the sample.

6. Describe how the volume of a gas sample depends on the number of moles in the sample, its pressure, and its temperature.

7. State and recognize Avogadro's Law.

8. State and recognize Boyle's Law.

9. State and recognize Charles' Law.

10. Describe when and why it is necessary to use the Kelvin temperature scale and be able to convert between Kelvin and Celsius.

11. State what is meant by STP and know the volume of one mole of gas at STP.

12. State and recognize the ideal gas law and know the value and units for the ideal gas constant.

13. Given three of these four values (P, V, n, T), use the ideal gas law to calculate the fourth.

14. Use measurements of the mass, volume, density, pressure, and temperature of a gas sample to calculate its molecular weight.

15. Calculate the new volume, pressure, temperature, or number of moles of a gas sample given an old set of conditions and the change imposed on the sample.

16. Define partial pressure and describe how it is related to the total pressure of a gas mixture.

17. State and recognize Dalton's Law of Partial Pressures.

18. Use Dalton's Law to solve problems involving gas mixture.

ASSIGNMENTS:

Reading in text - Read the chapter in your text on gases.

HBPA-6: Chapter 12

HBPA-7: Chapter 12

Practice problems in text-

HBPA-6: Chapter 12 exercises 28-46

HBPA-7: Chapter 12 exercises 26-44

TO BE TURNED IN:

Lab report - Determining the Value of the Gas Constant