Calculation of volume of a gas using Redlich Kwong Equation of State

This video shows how to calculate the volume of a gas using Redlich Kwong Equation of State. This question was asked in CET I paper of Mumbai University in December 17 . The question was 4(b)

[@pushpendrasingh-xp6ip]

Thank you sir for making problem look so easy 😀

[@dishantpatil5328]

Sir when we get multiple compressibility factors from its cubic equation. What does it resemble. Does it have any significance or just mathematical form.

[@profarvind]

If you solve it for superheated vapor condition it will give one real and two complex values of z. It you solve it for a state where the fluid is liquid then you get three values corresponding to three states, viz, saturated liquid, saturated vapor and mixture.

[@dishantpatil5328]

@@profarvind thanks sir for explaining the concepts 💡

[@dishantpatil5328]

Sir, I couldn't understand the concept of assuming the gas to be in superheated region. Despite asked to find its molar volume at 100°C. We considered the pressure to be 1 3rd of Pc to avoid errors in liquid vapour equilibrium states. But considered it at 500K Is unjustified.

[@profarvind]

Try doing the calculation at 100 degrees. You will find that it is in the two phase region.

[@dishantpatil5328]

@@profarvind sir in redlich kwong does the cubic equation forms a curve inside the liquid vapour equilibrium region

[@dishantpatil5328]

@@profarvind on one article i found the pressure has to be considered as P/Pc < T/2Tc

[@dishantpatil5328]

Is this valid

[@profarvind]

@@dishantpatil5328 Yes.