In this study we present new enthalpy of dilution measurements at T = (298.15, 323, 348, and 373) K and for molalities of less than 6.674 mol kg(-1). These new data fill a gap in the thermodynamic database between T = 298.15 K and T = 373 K where virtually no high-quality data at low to moderate molalities previously existed. These new data have been fitted with a Pitzer ion-interaction model with an ionic-strength dependent second virial coefficient. The model accurately reproduces the available osmotic, dilution enthalpy, heat capacity, and volumetric data to m = 8.0 mol kg(-1) and for 298.15 K less than or equal to T less than or equal to 373 K. The model is at least qualitatively correct to m approximate to 20 mol kg(-1) over the same temperature range. Data above T = 373 K are very limited, and with the exception of new dilution enthalpy data presented in this paper, we are not aware of any above p = 0.1 MPa or the vapor-saturated liquid surface.