Jw. Magee et N. Kagawa, SPECIFIC-HEAT CAPACITY AT CONSTANT VOLUME FOR (XNH(3)-X)H2O) AT TEMPERATURES FROM 300 TO 520 K AND PRESSURES TO 20 MPA((1), Journal of chemical and engineering data, 43(6), 1998, pp. 1082-1090
Specific heat capacities at constant volume (c(v)) of {xNH(3) + (1 - x
)H2O} (x approximate to 0.7, 0.8, 0.9) mixtures were measured with an
adiabatic calorimeter. Temperatures ranged from 300 K to 520 K, and pr
essures ranged from 3 MPa to 20 MPa. Measurements were conducted on si
ngle-phase liquid and compressed gaseous samples. The mixtures were gr
avimetrically prepared from high-purity substances and verified by che
mical analysis. Density was reported for initial and final end points
during each calorimetric experiment. The principal sources of uncertai
nty are the temperature rise measurement and the change-of-volume work
adjustment. The expanded relative uncertainty (with a coverage factor
k = 2 and thus a 2-standard-deviation estimate) for c(v) is estimated
to be 1% for liquid phase and 4% for gaseous results, and for density
it is 0.2%.