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Reference
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is the volume of the gas, T is the temperature on the absolute
scale, and the constant depends on the pressure and the
amount of gas present.
In 1802, Joseph Gay-Lussac played around with the
relationship between pressure and temperature and came up
with an equation a lot like Charles’s Law: P/T = Constant.
Generalized Gas Law
We can combine Boyle’s, Charles’s, and Gay-Lussac’s Laws
to express this generalized gas Law:
PV/T = Constant , where
the value of the constant depends on the amount of gas
present and t is the absolute (or Kelvin) temperature.
Ideal Gas Law
The Ideal Gas Law can be written in a slightly different
manner from the Generalized Gas Law:
PV/T = nR , or
PV = nRT . When written this way, it is called the Ideal-Gas
Law. R is the gas constant, and n is the number of moles of
gas. The gas constant can be examined experimentally as R =
0.082 liter atm/Kelvin moles. Knowing R, the fourth variable
can be evaluated if any three are known.
The gas Laws are valid for most gases at moderate
temperatures and pressures. At low temperatures and high
pressures, gases deviate from the above Laws because the
molecules are moving slowly at low temperatures and they are
closer together on the average at higher pressures.
Ideal vs. Real Gas
Gases are typified as ideal or real. The ideal gas follows
certain gas Laws exactly, whereas a real gas closely follows
these Laws only at low density. Ideal behavior can be ascribed
to a real gas if its molecules are separated by very large
distances, so that intermolecular attraction is negligible.