Measurement of the Heat Capacity of the Binary Fluid Mixture of Succinonitrile and Water Near the Upper critical Consolute Point Using Adiabatic Calorimetry

Madhujit Ghosh

The temperature dependence of the specific heat capacity of a binary fluid mixture of succinonitrile-water was measured at the upper critical consolute point with the help of a computer controlled, multi-stage, adiabatic calorimeter. An Apple Macintosh computer was used for data acquisition and control of the apparatus and to convert temperature data into heat capacity by using a custom script. Heat capacity of the binary fluid mixture, SCN-H2O, experienced a divergence at the critical temperature. We found the heat capacity anomaly at 55.695±0.0004 °C. The results confirmed the recently published theoretical and experimental values for the critical amplitude ratio. The background of the fits included the heat capacity of the cell. The system independent critical amplitude ratio for our system was found to be 0.60±0.01. The system dependent critical amplitude was found to be A+ = 1.28±0.02 J/K and A- = 2.11±0.02 J/K. The two-scale-factor universality was found to be X = 0.0172±0.023 and was found to be slightly larger than in recent experiments, but this inconsistency can be attributed to the inconsistencies in recent measurements of the correlation length of SCN-H2O.