1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

[Thermo] Derivation of compressibility factor vs reduced pressure

  1. May 4, 2010 #1
    1. The problem statement, all variables and given/known data
    derivation of compressibility factor vs. reduced pressure
    I am supposed to derive the graph by solving equations
    [​IMG]


    2. Relevant equations
    Van der Waals equation of state
    compressibility factor, Z = (Pv)/(RT)
    reduced pressure = P/critical pressure
    Z = f(Tr, Pr)


    3. The attempt at a solution
    I sat for 12 hours attempting to find a solution but just spent time trying to understand what I was doing instead.
    Is there a way to get the graph mathematically without using any values for critical pressure or temperature?

    Thank you!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. May 5, 2010 #2
    Compressibility charts are derived from experimental data from 10 gases such as propane, Nitrogen, Carbon Dioxide etc. Select a gas you have properties for such as propane. Tc propane is 370 K. Pc propane is 42.7 bar. Assume a constant temperature of let's say 555 K to generate the Tr=1.5 line. Vary pressure from 42.7 to 300 bars (Pr 1 to 6). Use propane tables to find v (specific volume) solve for Z. Plot Tr(Z,Pr)
     
  4. May 6, 2010 #3
    After solving the Van der Waals equation for the compressibility factor and
    deriving the critical temperature, pressure, and volume

    knowing that a horizontal inflection point occurs on the isotherm at critical point

    am I supposed to solve PV3-(Pb+RT)V2+aV-ab=0
    for the cubic root?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: [Thermo] Derivation of compressibility factor vs reduced pressure
Loading...