1 of 14 © Boardworks Ltd 2016 Particle Motion in Gases
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Particle Motion in Gases
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Particle Motion in Gases
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How do particles in a gas move?
The particles in a gas have enough kinetic energy to
overcome the attractions between particles. The particles
are spaced far apart and move randomly in all directions.
The temperature of a gas
is a measure of the
average kinetic energy of
the particles in the gas.
The pressure of a gas is
the force over a given area
exerted by the particles in
the gas when they collide
with the walls of the
container of the gas.
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Temperature and kinetic energy
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Temperature and absolute zero
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Kelvin and Celcius scales
0 Celcius (°C)200 400–273
273 Kelvin (K)0 473 673
The Celsius scale is defined using the freezing and boiling
points of water. This makes it less useful for calculations,
because 0°C is not at the beginning of the scale.
Using the Celsius scale for temperature is like measuring
mass on a scale that takes 273kg as zero mass and
measures anything less than that as negative mass!
The Kelvin scale starts from absolute zero (–273°C).
A difference in temperature of 1K is the same as a difference
of 1°C, so it is easy to convert between the two scales.
–100
173
100
373
300
573
500
773
–200
73
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Converting between scales
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Gas pressure
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Particle Motion in Gases
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Volume, pressure and temperature
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How does temperature affect pressure?
The higher the temperature of a gas, the greater the kinetic
energy of the particles.
This increases the pressure of the gas when volume
is constant.
Pressure and temperature are directly proportional.
higher temperature higher pressure
Particles with a higher kinetic energy move faster and
collide with the walls of the container more frequently and
with greater force.
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Particle Motion in Gases
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Glossary
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Multiple-choice quiz