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Unformatted text preview: rticle attractions.
The effect of interparticle attraction
Van der Waals
equation for n
moles of a real gas n 2a
( P + 2 )(V ! n b ) = n R T
V The constant a relates to
The constant b relates to
factors that influence the
attraction between particles.
Different compounds have different a and b values Vapor Pressure
5-13 A special case of a gas I a gas at equilibrium with a liquid
The partial pressure of a such a gas cannot be increased or decreased as long as there are both
gas and liquid present
If you compress the gas, some of the gas get converted to liquid
If you expand the gas, some of the liquid evaporates
The pressure of a gas at equilibrium with a liquid is called the liquid’s vapor pressure
The vapor pressure of a liquid is a function of temperature it is a function of the kind of liquid,
and it is a function of the purity of the liquid
For a pure liquid at a constant temperature, it is constant Kinetic Energy and Gas Behavior
t a given T, all gases in a sample have the same
Kinetic Energy and Gas Behavior
verage kinetic energy. At a given T, all gases in a sample have the same average kinetic energy Ek = 1
2 mass x speed2 kinetic energy depends on the mass and the speed of a particle
inetic energat the pends a heavier gas e mass and the slowly than a lighter one
y de same T, on both th particle moves more peed of a particle.
t the same T, a heavier gas particle moves more
lowly than a lighter one. 16:27 16:27...
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- Winter '13