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Gas Density Equation

by kinogram
Tags: density, equation
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kinogram
#1
Jul23-14, 02:59 PM
P: 24
If the equation below is correct

[itex]n = PV / (R/T)[/itex]

where :

n = gas density in mole / m
P = pressure in Pascal
V = volume in m
R = ideal (individual) gas constant
T = temperature in Kelvin


Given that the individual gas constant - R for H2 = 4124 J / kg K

Then 1 m of H2 at 101325 Pa and 273.15 K
should have a molar density of 0.089949

and

1 m of H2 at 5 x 10-18 Pa and 2.7 K
should have a molar density of 4.49 x 10-22


are these calculated results correct?




.
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berkeman
#2
Jul23-14, 04:31 PM
Mentor
berkeman's Avatar
P: 41,320
Quote Quote by kinogram View Post
If the equation below is correct

[itex]n = PV / (R/T)[/itex]

where :

n = gas density in mole / m
P = pressure in Pascal
V = volume in m
R = ideal (individual) gas constant
T = temperature in Kelvin


Given that the individual gas constant - R for H2 = 4124 J / kg K

Then 1 m of H2 at 101325 Pa and 273.15 K
should have a molar density of 0.089949

and

1 m of H2 at 5 x 10-18 Pa and 2.7 K
should have a molar density of 4.49 x 10-22


are these calculated results correct?




.
There is an algebra error in your starting equation... See http://en.wikipedia.org/wiki/Ideal_gas_law
kinogram
#3
Jul23-14, 05:37 PM
P: 24
Thanks.. I see that now



[itex]PV=nRT[/itex]

Then

[itex]n=PV/(RT)[/itex]


however it looks like the calculations were made correctly according to the proper equation






.


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