What is the density (in g/L) of hydrogen gas at 21.0 C and a pressure of 1640 psi?

1 Answer
Aug 6, 2017

Answer:

You have specified a pressure of #1640*"psi"#, which is not the same as #1640*"psig"#......

Explanation:

We must first convert to kosher units.......

#1*atm-=14.7*"psi"#

And thus #1640*"psi"=(1640*"psi")/(14.7*"psi"*atm^-1)=111.6*atm.#

This is a high pressure, and we use the Ideal Gas for a first approx. If you want a better estimate, you need to find another equation of state.

WE know that #PV=nRT#, and #P/(RT)=n/V=("mass"/"molar mass")/(V)#

And so....#P/(RT)xx"molar mass"="mass"/V=rho_"gas [density](https://socratic.org/chemistry/measurement-in-chemistry/density)"#

And thus #rho=(111.6*atmxx2.015*g*mol^-1)/(0.0821*L*atm*K^-1*mol^-1xx294.15K)#

#=9.31*g*L^-1#

Note that #"Kelvin temperature"# is specified.........And given the pressure, (which is unreasonably hi), this is a very high gas density.