Panel 4: The Ideal Gas Law
The generic physical behavior of gases is described by
the ideal gas law, which is "pressure times
volume is equal to the product of number of moles,
the gas constant R and temperature, or "pee vee equals
en ar tee". Remember, T is the absolute temperature
(always in Kelvins). R is a "constant of nature" called
the gas constant, and has the value 0.0821
when pressure is measured in atmospheres, volume in
liters, number of particles in moles, and temperature
in Kelvin.
This very general "law" is not perfect, but is remarkably accurate
for most gases. It is least accurate when the gas in question is
near conditions where it would become a liquid or solid; that is,
at low temperatures and high pressures. Use the ideal gas law
with confidence, but remember that it applies only to gases and
will give horribly wrong answers if applied to other states of
matter!