Kinetic Theory

Ever wonder why?
Episode 901
Kinetic Theory
• Gases are composed of small, separate
particles called molecules.
• Gas molecules are in constant motion.
• All collisions between particles are
perfectly elastic.
• The molecules of a gas display no
attraction or repulsion for one another.
• The average kinetic energy of the
molecules is directly proportional to the
Kelvin temperature of the gas.
Episode 901
Ideal Gas
• Gas whose behavior conforms to the
kinetic theory – it is theoretical.
• All gases behave as an ideal gas unless
temperature is very low or pressure is
very high.
Episode 901
Gas Pressure
• Pressure = force / area
• Atmospheric Pressure –
the pressure the
earth’s atmosphere
exerts due to its
Episode 901
• Instrument used to
measure atmospheric
• Invented by Torecelli
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Normal Atmospheric Pressure
Also called standard pressure
760 mm Hg
760 torr
1 atm (atmosphere)
101.3 kPa
• Standard Temperature and Pressure
• 1 atm
• 0⁰Celsius
Episode 901
• Instrument used to measure
gas pressure
• U-shaped tube partially filled
with mercury
• One end open to confined
• One end open to
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CR Question 1
• What would be the density of a 10 gram
object that displaces two milliliters of
a. Five
b. 20
c. Five grams per milliliter
d. 20 grams per milliliter
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CR Question 2
• Is oxygen a metal, nonmetal, or
a. Metal
b. Nonmetal
c. Metalloid
Episode 901
Review Question 1
• Does the average kinetic energy of the
gas particles in an inflated inner tube
increase or decrease if the sun heats
the inner tube from 20 degrees Celsius
to 30 degrees Celsius?
a. Increase
b. Decrease
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Review Question 2
• What is the name of the instrument
used to measure the pressure of a
confined gas?
a. Manometer
b. Pascalometer
c. Pressureometer
d. Barometer
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Review Question 3
• STP is
a. Standard temperature and pressure
b. Zero degrees Celsius and one atmosphere
c. Zero degrees Celsius and one hundrend one
point three kilopascals
d. All of these
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Review Question 4
• Under what conditions of temperature and
pressure does the behavior of a real gas
differ from that of an ideal gas?
a. Very high temperature and very high
b. Very high temperature anf very low
c. Very low temperature and very low
d. Very low temperature and very high
Episode 901
Review Question5
• The kinetic theory
a. Is a model
b. Explains gas behavior
c. Neither a nor b
d. Both a and b
Episode 901

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