This research, part of the Experimental Physical Chemistry Program, is in the area of the Thermodynamic and Thermophysical Properties of Solutions. The research determines the thermodynamic behavior of binary fluid mixtures near their critical point. The results of this research will shed light on the interaction of fluids. It is also expected to be useful in providing data and estimation schemes for the design of chemical extraction procedures that are of importance to technology. The research will be performed by undergraduate students in an institution that is committed to undergraduate research.