Chapter 6
Lesson 3-The behavior of gases
Understanding Gas Behavior
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Gases behave differently than solids and liquids
Changes in temperature, pressure, and volume affect
gases
Kinetic molecular theory- is an explanation of how
particles in matter behave:
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1.Small particles make up all matter
2.The particles are in constant, random motion
3.The particles collide with other particles, other objects, or
the sides of the container
4.When particles collide no energy is lost.
Understanding Gas behavior
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Gas molecules collide with the container they are in.
As a result, the molecules exert a pressure on their
container.
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Pressure- the amount of force applied per unit of area
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The more a gas is compressed then the higher the
pressure
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Pressure and Volume
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At a constant temperatureBigger container ( more volume) then less pressure
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The particles hare more room to move so less particles are
bumping into each other and the container
Smaller container (less volume) then more pressure
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The particles have less room to move so they are constantly
bumping into each other
So an inverse proportion
It is also a famous law- Boyle’s Law
Boyle’s law
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Robert Boyle- British (1627-1691)
Boyle’s law- if the pressure of a gas increases if the
volume of the gas decreases, and if the volume of the gas
increases then the pressure decreases
Temperature and Volume
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At a constant pressureAt a low temperature, the average kinetic energy is low
so the particles are close together so the volume of the
gas is low.
At high temperature, the average kinetic energy is
increased so the volume of the gas is increased.
They are directly proportional
This is another famous law- Charles’s law
Charles’s Law
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Jacque Charles (1746-1823)- French scientist
Charles’s law states- that the volume of a gas increases
with increasing temperature, if the pressure is constant.