Chemical Thermodynamics 1.6 - Critical Point

Short physical chemistry lecture on the critical properties of non-ideal gases.

The critical point of a gas is the point where the first and second derivative of pressure with respect to molar volume is zero at the same temperature. All gases have a single unique critical point, which can be used to parametrize the van der Waals equation of state.

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[SoumilSahu]

this 7 minute video taught me more than my professor could in 2 days.
you're an amazing teacher!

[nkyu]

For a case of gas to liquid, does the slope of the curve approximates to 0 because gas particles become liquid and don't increase the pressure?

and is the line left to the coexistence curve imaginary? because there's no gas anymore.

[Eric-qzhz]

How did you jump to the values of the three critical quantities?

[SpockCrafting]

Hi! Could you clarify something for me? Won't the first and second derivatives of pressure with respect to volume both equal zero at multiple temperatures? But there is only one temperature where the critical point exists. So those derivatives alone don't define the critical point?

[mar]

Really good video! Thank you.. One question: Can the difference in the critical point be explained by the differences of the van der walls parameters (a) and (b)?

[nonsomgbechi]

Hey, Thank you for the videos.
I'm doing Thermodynamics and Kinetics this semester and they've been wonderful.

At your subcritical isotherm (T2), you said "the pressure will start going up with volume" I think you probably meant pressure becomes constant or something.
You want to clarify this?

[manzilbuet-bme]

Thank you, but can't find the difference between video 1 & 2.