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[Thermo] Derivation of compressibility factor vs reduced pressure 
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#1
May410, 10:55 PM

P: 2

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 2. Relevant equations Van der Waals equation of state compressibility factor, Z = (Pv)/(RT) reduced pressure = P/critical pressure Z = f(T_{r}, P_{r}) 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
May510, 03:35 PM

P: 374

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)



#3
May610, 06:42 PM

P: 2

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 PV^{3}(Pb+RT)V^{2}+aVab=0 for the cubic root? 


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