how 1 lbmol equals to 379.4 ft³ or scf

1 lbmole = (Weight of Carbon)/(M.wt. of Carbon)
= (12 lb mol ) / 12
= (5443.11 gm mol) / 12
= 453.5925 gm mol
Now,
1 gm mole= 23.70336 L (this is @ 60ºF or 15.55ºC)
= 0.02370336 m³
= 0.83643358 ft³ or say scf
and we can easily compute that 1 lbmol = (453.5925) x (0.83643358) scf
= 379.4 ft³ or scf
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[NOTE :1gm mole = 22.414 L/mol at 0 °C]