Answer:
The number of pounds of helium n = 666.995 lbm
Explanation:
Given that :
the volume V = 68000 ft³
the temperature T = 80 f = (80 + 460)°R =540°R
the pressure P = 14.2 psia
Using the ideal gas equation PV =nRT to determine the number of pounds of helium within, we have :
n = PV/RT
where;
R = 2.6809 psia. ft³/lbm.R (from the tables of A-1E for helium)
n = (14.2 × 68000)/(2.6809 × 540)
n = 965600/1447.686
n = 666.995 lbm
∴
The number of pounds of helium n = 666.995 lbm
