Thermodynamic Study of (CaCl2 + N,N-Dimethylacetamide + H2O) System Based on Potentiometric Measurements at T = 298.2 K

In this research, thermodynamic study of (CaCl2 + N,N-dimethylacetamide + H2O) ternary system were performed using the potentiometric method. The potentiometric measurements were carried out on the galvanic cell of type: Ag-AgCl|CaCl2 (m), DMA (w), H2O (1 – w)|Ca-ISE in various mass fractions of N,N-dimethylacetamide in water (0, 0.10, 0.20, 0.30) in the molality ranging from 0.0100 to 4.000 mol.kg-1 at T = 298.2 K and P = 0.1 MPa. Thermodynamic properties were determined using the Pitzer ion-interaction model. Subsequently, unknown parameters for this model were determined and utilized to calculate the values of the mean activity coefficients, the osmotic coefficients, the excess Gibbs free energy and the solvent activity for the system under investigation.