Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Kinetic theory


Published on

  • Be the first to comment

Kinetic theory

  1. 1. Gases Part 1: Kinetic Molecular Theory
  2. 2. Kinetic Molecular Theory <ul><li>describes the behavior of gases in terms of particles in motion. </li></ul><ul><li>makes several assumptions about the </li></ul><ul><ul><li>size </li></ul></ul><ul><ul><li>motion, and </li></ul></ul><ul><ul><li>energy of gas particles. </li></ul></ul>
  3. 3. Assumptions <ul><li>Particle size </li></ul><ul><li>Particle motion </li></ul><ul><li>Particle energy </li></ul>
  4. 4. Particle Size <ul><li>Gases consist of small particles that are separated from one another by empty space. </li></ul><ul><li>The volume of the particles is small compared with the volume of the empty space. </li></ul>
  5. 5. Gas has Mass
  6. 6. Particle motion <ul><li>Gas particles are in constant, random motion. </li></ul><ul><li>Particles move in a straight line until they collide with other particles or with the walls of their container. </li></ul>
  7. 7. Elastic Collisions <ul><li>Collisions between gas particles are elastic. </li></ul><ul><li>An elastic collision is one in which no kinetic energy is lost. </li></ul>
  8. 8. Particles move very fast
  9. 9. Particle energy <ul><li>Kinetic energy is a function of the mass and speed of a particle. </li></ul><ul><li>In a sample of a single gas, all particles have the same mass but all particles do not have the same velocity. </li></ul><ul><li>Therefore, all particles do not have the same kinetic energy. </li></ul>
  10. 10. Kinetic Energy and Momentum
  11. 11. Properties of Gases <ul><li>Low density </li></ul><ul><li>Compressible </li></ul><ul><li>Diffuses </li></ul>
  12. 12. Low density <ul><li>Density – mass per unit of volume (g/cm 3 ) </li></ul><ul><li>Density of gasses is much lower than the density of solids or liquids. </li></ul>
  13. 13. Compressible <ul><li>Gasses can be compressed </li></ul><ul><li>Compression – can be pushed into a smaller volume </li></ul><ul><li>Expansion – can be pulled into a greater volume </li></ul>
  14. 14. Diffusion <ul><li>the movement of one material through another. </li></ul><ul><li>particles diffuse from an area of high concentration to one of low concentration </li></ul>
  15. 15. Temperature and Pressure <ul><li>Kinetic theory explains the temperature and pressure of gasses </li></ul><ul><ul><li>How fast the molecules of a gas are going </li></ul></ul><ul><ul><li>How heavy the molecules are </li></ul></ul>
  16. 16. Temperature <ul><li>Temperature is a measure of the average kinetic energy of the particles in a sample of matter. </li></ul>
  17. 17. In other words… <ul><li>Temperature is related to </li></ul><ul><ul><li>How fast the molecules of a gas are moving </li></ul></ul><ul><ul><li>How often the molecules hit the walls of the container </li></ul></ul>
  18. 18. Gas has temperature
  19. 19. Pressure <ul><li>defined as force per unit area. </li></ul><ul><li>Gas particles exert pressure when they collide with the walls of their container. </li></ul>
  20. 20. In other words… <ul><li>Pressure is related to </li></ul><ul><ul><li>How fast the molecules of a gas are moving </li></ul></ul><ul><ul><li>How much the particles weigh </li></ul></ul><ul><ul><li>How hard the molecules hit the walls of the container </li></ul></ul>
  21. 21. Gas has pressure
  22. 22. Measuring Pressure <ul><li>A barometer is an instrument used to measure atmospheric pressure. </li></ul><ul><li>A manometer is an instrument used to measure gas pressure in a closed container. </li></ul>
  23. 23. Pressure Units <ul><li>SI unit of pressure is the pascal (Pa). It is named for Blaise Pascal. </li></ul><ul><li>One pascal is equal to a force of one newton per square meter: 1 Pa= 1 N/m 2 . </li></ul>
  24. 24. Other Pressure Units <ul><li>engineers often report pressure as pounds per square inch (psi). </li></ul><ul><li>pressures measured by barometers and manometers can be reported in millimeters of mercury (mm Hg). </li></ul>
  25. 25. Air pressure <ul><li>At sea level, the average air pressure is 760 mm Hg when the temperature is 0°C. </li></ul><ul><li>Air pressure often is reported in a unit called an atmosphere (atm). One atmosphere is equal to 760 mm Hg or 760 torr or 101.3 kilopascals (kPa). </li></ul>
  26. 26. Temperature and Pressure <ul><li>Temperature and pressure are directly proportional </li></ul><ul><li>As one goes up, the other goes up </li></ul><ul><li>As one goes down, the other goes down </li></ul>
  27. 27. Temperature and Pressure
  28. 28. Temperature and volume
  29. 29. Volume and Pressure