Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Mass flow control and ideal gas calculation

  1. Mar 10, 2009 #1
    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
     
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted