A method for caffeine extraction uses carbon dioxide held beyond it.
The parameters describing this state can be computed as [read slowly] 8a over 27 bR ["8-a over 27 b-r"] and a over 27 b2 ["a over 27 b-squared"], where a and b are the van der Waals coefficients. It occurs at the intersection of the binodal and spinodal curves. The first and second derivatives of pressure with respect to volume are equal to zero here. Density fluctuations at this point lead to cloudiness known as (*) "opalescence." A method for caffeine extraction uses carbon dioxide held beyond it. For 10 points, name this point beyond which the liquid and gas phases are indistinguishable
The parameters describing this state can be computed as [read slowly]
critical point [accept critical temperature or pressure]