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Non-Ideal Gases: How do you relate P, V, T?. Non-ideal if:. Step 1 : Is the gas ideal or non-ideal? (Page 192). If ideal, use PV = nRT. Step 2 : Non-ideal? Choose an approach Equation of State Compressibility Factor. Equations of State give analytic solutions
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Non-Ideal Gases: How do you relate P, V, T? Non-ideal if: Step 1: Is the gas ideal or non-ideal? (Page 192) If ideal, use PV = nRT • Step 2: Non-ideal? Choose an approach • Equation of State • Compressibility Factor • Equations of State give analytic solutions • There are several EOS to choose from • SRK explained on p. 203 • “plug and chug” to solve Eqn 5.3-7 below • Compressibility factor “Z” • PV = znRT (z is “fudge factor”) • Calculate (2 of 3) Pr, Tr, Vr • Plots on p. 208-210 • Find where Pr, Vr, or Tr intersect and read Z PV = znRT Notes: 1. Non-ideal gases use “reduced” values for P, T, V so that “universal” equations and plots can be used. Otherwise, every gas (e.g., nitrogen, propane, etc) would have different plots and equations relating P, T, V. 2. is the molar volume = volume divided by the moles (vol/mol) 3. Kay’s Rule: If you have more than one component, the “pseudocritical” T and P are “weighted” by their mole fractions (pg. 211)