# Mass flow control and ideal gas calculation

1. Mar 10, 2009

### Enigmata

1. The problem statement, all variables and given/known data
I have an experimental setup consisting of a 755ml stainless steel cylinder being fed with Hydrogen from atmospheric unitl 10 bar. I am using a Brooks Mass flow controller to measure and control the flow of Hydrogen into the cylinder while at the same time recording the flow rate. Once flow stop a seperate pressure transmitter indicates 10 bar pressure, therefore the cylinder should be full. The recorded amount of Hydrogen show 12.8L.

2. Relevant equations
In order to prove the above, I have done the following calculation:
T=297.15K P=1000kPa Z=1.001 R=8.314472*J/K/mol MM=2.0158gm/mol V=0.755L
Z=Hydrogen compressability factor
Rh= R/MM=4.1246155*J/K/mol

n=(P*V)/(Z*Rh*T)
n=0.615 mol
mass=MM*n=1.241x10^-3kg

3. The attempt at a solution
However I want to know the actual gas volume in liters in the cylinder, therefore
Volume=Mass/Density
= 1.241x10^-3kg/0.08988g/L
=13.8L

The result is out with 1 liter in this case, and increase much more as the pressure aproach 100 bar. What am I doing wrong ???
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution