1 / 24

Gas Laws

Gas Laws. Boyle’s Law. Volume and pressure are inversely related at constant temperature P 1 V 1 = P 2 V 2 @ constant T. Boyle’s Law and Kinetic Theory. If the average speed of the molecules stays the same…

snow
Download Presentation

Gas Laws

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. Gas Laws

  2. Boyle’s Law • Volume and pressure are inversely related at constant temperature • P1V1 = P2V2@ constant T

  3. Boyle’s Law and Kinetic Theory • If the average speed of the molecules stays the same… • and the tank volume increases… • the molecules hit the sides of the container less often.

  4. Absolute Temperature • Absolute temperature is measured in Kelvins (K) • One Kelvin is equal in size to one Celsius degree • K = oC + 273 • oC = K - 273

  5. Charles’s Law • Volume and temperature are directly related at constant pressure • V1/T1 = V2/T2@ constant P

  6. Charles’s Law and Kinetic Theory • If the number of collisions stays the same… • and the tank volume increases… • the molecules must be moving faster on average.

  7. Gay-Lussac’s Law • Pressure and temperature are directly related at constant volume • P1/T1 = P2/T2@ constant V

  8. Gay-Lussac’s Law and Kinetic Theory • If the volume of the container stays the same… • and the molecules are moving faster on average… • the molecules must be colliding with the walls of the container more often and with more force.

  9. Combined Gas Law • A combination of Boyle’s, Charles’s, and Gay-Lussac’s Laws, where nothing need be held constant

  10. Gas Laws

  11. Avagadro’s Hypothesis • Equal volumes of gases contain equal numbers of moles (n) when compared at the same temperature and pressure • molar volume of “any” gas: 1 mol = 22.4L @ STP

  12. If P, V & T are the same, then n is the same (constant)

  13. Ideal Gas Law • Combines all four key physical properties of gases • PV = nRT • R = 0.082 (atm)(L)/(mol)(K) • R = 8.31 (kPa)(L)/(mol)(K) • R = 62.4 (mmHg)(L)/(mol)(K)

  14. R = 0.082 (atm)(L)/(mol)(K) • R = 8.31 (kPa)(L)/(mol)(K) • R = 62.4 (mmHg)(L)/(mol)(K) • STP: T=273K • P= 101.3 kPa • = 1.0 atm • = 760 mmHg

  15. Dalton’s Law of Partial Pressures • The total pressure of a mixture of gases is the sum of the partial pressures of the individual gases • PT = P1 + P2 + P3 + .......

  16. Dalton’s Law

  17. Effusion • Effusion is the movement of gas molecules through an extremely tiny opening into a region of lower pressure • helium escaping a balloon • air leaking from a tire

  18. Diffusion • Diffusion is the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout the system • mixing of gases

  19. Graham’s Law of Effusion • The rate of effusion (or diffusion) of a gas is inversely proportional to the square root of its molar mass (at constant T and P). • Molecules of lower molar mass diffuse and effuse faster.

  20. Due to kinetic energy considerations (KE = 1/2mv2), when two bodies of different mass have the same kinetic energy (~ same T), the lighter body moves faster.

More Related