qThe ideal gas law can
be applied to the combination of atmospheric gases or to
individual gases.
qThe value of gas
constant for the particular gas under consideration depends
on its molecular weight:
q Rgas = R* /
Mgas
q where R* = universal gas constant =
8314.3 J deg-1 kg-1
qThe gas constant for
dry atmospheric air is:
q Rair = R* / Mair = 8314.3/28.97 = 287 J deg-1 kg-1
q (Mair @ 0.80*MN2 + 0.20*MO2 = 0.80*28 + 0.2*32 = 28.8)
qThe gas constant for
water vapor is:
q Rvapor = R* / Mvapor = 8314.3/18.016
q = 461 J deg-1 kg-1