PROBLEM 14.3
KNOWN: Partial pressures and temperature for a mixture of CO2 and N2.
FIND: Molar concentration, mass density, mole fraction and mass fraction of each species.
SCHEMATIC:
2A
A CO , 44 kg / kmol→=M
2B
B N , 28 kg / kmol→=M
ASSUMPTIONS: (1) Perfect gas behavior.
ANALYSIS: From the equation of state for an ideal gas,
i
ip
C.
T
=ℜ
Hence, with pA = pB,
AB 23
1bar
CC8.314 10 m bar / kmol K 298 K
−
==
×⋅ ⋅×
3
AB
C C 0.040 kmol / m .== <
With iii
C,=M
ρ
it follows that
33
A44 kg / kmol 0.04 kmol / m 1.78 kg / m
ρ
=× = <
33
B28 kg / kmol 0.04 kmol / m 1.13 kg / m .
ρ
=× = <
Also, with
iiii
xC/C=Σ
find
AB
x x 0.04 /0.08 0.5== = <
and with
iii
m/
ρ
ρ
=Σ
find
()
A
m 1.78/ 1.78 1.13 0.61=+=
<
()
B
m 1.13/ 1.78 1.13 0.39.=+= <
