How do i obtain specific volume?

Question

Given Helium with molecular weight of 4. Is it possible to convert this to specific volume?

Given Helium with molecular weight of 4. Is it possible to convert this to specific volume?

Please show me the calculations.

Answer 1

Physical Properties
Molecular Symbol: He
Molecular Weight: 4.003
Boiling Point @ 1 atm: -452.1°F (-268.9°C, 4oK)
Freezing Point @ 367 psia: -459.7°F (-272.2°C, 0oK)
Critical Temperature: -450.3°F (-268.0°C)
Critical Pressure 33.0 psia: (2.26 atm)
Density, Liquid @ B.P., 1 atm: 7.798 lb./cu.ft.
Density, Gas @ 32°F (0°C), 1 atm: 0.0103 lb./cu.ft.
Specific Gravity, Gas (Air = 1) @ 32°F (0°C), 1 atm: 0.138
Specific c Gravity, Liquid @ B.P., 1 atm: 0.125
Specific c Volume @ 32°F (0°C), 1 atm: 89.77 cu.ft./lb.
Specific c Volume @ 68°F (20°C), 1 atm: 96.67 cu.ft./lb.
Latent Heat of Vaporization: 34.9 Btu/lb. mole
Expansion Ratio, Liquid to Gas, B.P. to 32°F (0°C): 1 to 754

Answer 2

Specific Volume (v) = RsT/P for an ideal gas.

T is Temperature in Kelvins
P is Pressure in
Rs is the specific gas constant, and can be calculated as:
Rs = R/M (M is molar mass of gas)

M = 4 g/mol, converted to .004 kg/mol
R = the Universal Gas Constant = 8.314472 J/(mol * K) where K = temperature in Kelvins

Rs = R/M = 2078.618 J/(K * kg). Joules can be converted to Newton * meters, leaving 2078.618 (Nm)/(K*kg)
N = Newton
m = meters
K = degrees Kelvin)
kg = kilograms.

so:
v = 2078.618 (N * m)/(K * kg) * T/P

P is typically left at 1 atmosphere (unless otherwise defined) which =

v = (2078.618 (N * m)/(K * kg) * T)/ 101 325 N/m^2
v = 0.02051 m^3 / K * kg * T

For T, we'll use 0 degrees Celsius, which equals 273.15 degrees Kelvin (Tc = Tk + 273.15).

v = 0.02051 m^3 / K * kg * 273.15 K

This gives you a final answer of:
v = 5.6035 m^3/kg @ 1 atm & 0 degrees Celsius

Check:
Specific Volume is the inverse of Density.
From http://en.wikipedia.org/wiki/Helium we can can find the density of Helium @ 1 atm & 0 degrees Celsius is 0.1786 g/L.

1 g/L = 1 kg/m^3
d = v ^-1
d = (5.6035 m^3/kg) ^-1
d = 0.1786 kg/m^3 = our calculation matches the reference book.