Thermodynamics of complexation of aqueous 18-crown-6 with barium ion:: apparent molar volumes and apparent molar heat capacities of aqueous (18-crown-6+barium nitrate) at temperatures (278.15 to 393.15) K, at molalities (0.02 to 0.33) mol • kg-1, and at the pressure 0.35 MPa

We have measured the densities at T = (278.15 to 368.15) K and heat capacities at T = (278.15 to 393.15) K of aqueous solutions of {18-crown-6 + Ba(NO3)(2)} at molalities m = (0.02 to 0.33) mol center dot kg(-1) and at the pressure 0.35 MPa. We have applied Young's rule and have accounted for chemical speciation and relaxation effects to resolve V-phi and C-p,C-phi to include contributions of the 18-crown-6-Ba2+(aq) complex in the mixture. We have also calculated estimates of the change in volume A,. V, the change in heat capacity Delta C-r(p,m), the change in enthalpy Delta H-r(m), and the equilibrium quotient 1g Q for formation of the complex at T = (278.15 to 393.15) K and m = (0 to 0.33) mol center dot kg(-1) in the mixture. (c) 2005 Elsevier Ltd. All rights reserved.