Kinetic Theory

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Kinetic Theory Gas Pressure

• By Beth Gillespie, Brendan Dougherty, Katie
  Erikson,
• Brittney Monaghan, Erin Shea

2
Overview

• Kinetic Theory
• Kinetic Energy
• Basic Assumptions
• Gas Pressure
• Atmospheric Pressure
• Pascal
• Standard Atmosphere
• Mercury and Aneroid Barometers

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Kinetic Theory

• States that the tiny particles in all forms of
  matter are in constant motion
• Kinetic energy
• Energy an object has because of its motion

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Basic Assumptions

• A gas is composed of particles.
• Particles in a gas move rapidly, in a constant,
  random motion.
• During collisions, kinetic energy is transferred
  without loss from one particle to another

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Gas Pressure

• Gas particles collide with other molecules and
  cause pressure
• If there are no particles, there can not be
  collisions, and therefore there is no pressure
• Vacuum

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Gas Pressure

• Gas pressure is the force that gas exerts on the
  walls of its container
• Pressure applied to an object from the inside

http//www.indiana.edu/geog109/topics/10_ForcesW
inds/GasPressWeb/PressGasLaws.html
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Atmospheric Pressure

• Pressure applied to an object from the outside
• Results from collisions of air molecules with
  objects
• Decreases as elevation increases

http//www.indiana.edu/geog109/topics/10_ForcesW
inds/GasPressWeb/PressGasLaws.html
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Units of Measurement

• SI Unit of Pressure is the pascal (Pa)
• Atmospheric Pressure at sea level is 101.3 kPa
• 1atm 760 mm Hg 101.3kPa
• Barometers
• Devices used to measure atmospheric pressure

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Mercury Barometer

• 1 atm 29.92 inches on the barometer
• Pressure on mercury causes mercury in tube to
  rise
• The more pressure applied to the pool of mercury
  at bottom, the more the mercury rises in the tube

http//www.atmos.washington.edu/2005Q3/101/LINKS-h
tml/MercuryBarometer.jpg
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Aneroid Barometers

• Do not contain mercury
• Atmospheric pressure on the barometer controls
  movement of pointer
• Indicates pressure

http//www.yourdictionary.com/images/ahd/jpg/A4ane
roi.jpg
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References

• Wilbraham, Antony, Dennis Staley, Michael Matta,
  and Edward Waterman.Chemistry. Student. Upper
  Saddle River, NJ Prentice Hall, 1997. (267-269)
• http//www.indiana.edu/geog109/topics/10_ForcesW
  inds/GasPressWeb/PressGasLaws.html
• http//www.atmos.washington.edu/2005Q3/101/LINKS-h
  tml/MercuryBarometer.jpg
• http//www.yourdictionary.com/images/ahd/jpg/A4ane
  roi.jpg