1 / 18

Chapter 12 The Behavior of gases

Chapter 12 The Behavior of gases. 12.1 The Properties of Gases. Things you will learn. Describe the properties of gas particles Recall the basic assumptions of the kinetic theory of gases. The parts of the kinetic theory of gases.

winter
Download Presentation

Chapter 12 The Behavior of gases

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 12The Behavior of gases 12.1 The Properties of Gases

  2. Things you will learn • Describe the properties of gas particles • Recall the basic assumptions of the kinetic theory of gases

  3. The parts of the kinetic theory of gases • Gases consist of hard spherical particles, usually atoms or molecules • Their size is so small that their volumes can be considered insignificant • There is lots of empty space in between particles • This empty space makes gases compressible

  4. More parts of the kinetic theory of gases • There are no attractive or repulsive forces between particles of gas • As a result, gases can fill containers and take the shapes of their containers • The pressure measured at any point inside the container will be the same

  5. More parts of the kinetic theory of gases • Gas particles move rapidly in constant random motion • The particles travel in straight paths independently of each other • The collisions between particles is perfectly elastic, maintaining the average kinetic energy of the system • And, of course, the average kinetic energy of the system is directly proportional to the temperature in Kelvins

  6. Variables that describe gases • Pressure (P) in kilopascals • Volume (V) in liters • Temperature (T) in Kelvins • Number of particles (n) in moles

  7. What affects gas pressure??? • When you pump up a tire, you may change the volume of the tire marginally, but you really change the pressure a lot

  8. But the tube should really be in a tire that can contain the gas

  9. These guys blew up the tire quickly, but now they have to add air quickly. Why?

  10. So gas pressure is affected by the number of particles • Keeping the volume and temperature constant, adding more gas to a system increases the pressure • They have a direct relationship • P~n

  11. If I have one mole of helium in a rigid container at 250 C and increase the amount of helium by one mole, keeping the temperature constant, what will the new pressure of the container be?

  12. So gas pressure is affected by the volume • Keeping the number of particles and the temperature constant, increasing or decreasing the volume decreases or increases the pressure • They have an inverse relationship • P~1/V

  13. If I have one mole of helium in a container at 250 C and increase the volume of the container by 2, keeping the temperature and the amount of particles constant, what will the new pressure of the container be?

  14. So gas pressure is affected by the temperature • Keeping the volume and number of particles constant constant, adding heat to a system increases the pressure • They have a direct relationship • P~T

  15. If I have one mole of helium in a container at 250 C and increase the temperature of the container to 175°C, keeping the volume and the amount of particles constant, what will the new pressure of the container be?

  16. If I have one mole of helium in a container at 250 C and increase the temperature of the container to 175°C, keeping the volume and the amount of particles constant, what will the new pressure of the container be? Remember that gas laws use Kelvins rather than °C; 25°C = 298K, and 175°C = 448K New pressure will be 448/298 what the original was, or ~ 1.5 times as much

  17. Next chapter-gas laws • Boyle’s Law • Pressure-volume relationship • Charles’s Law • Temperature-volume relationship • Gay-Lussac’s Law • Temperature-pressure relationship

  18. The chapter after that • The combined gas laws • Combines the three variables: temperature, pressure and volume P1x V1 = P1x V1 T1T1 • The ideal gas law combines all three of these things and the number of particles PV=nRT

More Related