Precision measurements of densities and thermal dilation of water between 5.deg. and 80.deg.

Abstract

The densities of air-free water have been measured with an accuracy of about 3 ppm between 5°and 80°C. Since the relative measurements were more precise than the absolute measurements, the densities were adjusted to bring them into agreement with the defined density at 4°C. This was done by calculating the weight of the water in the dilatometers from the densities of Chappuis as expressed by the Tilton and Taylor equation up to 40°C. Comparisons are made with other literature values, particularly above 40°C, including a close examination of the water density data of Owen et al. Finally, a modified form of the Tilton and Taylor equation was derived to fit the water density data from 0-80°C with a mean absolute deviation of 0.7 X 10-e g/ml.Since we believe these values represent the best data available at this time, a table of water density values calculated from this equation at 0.1°intervals over the entire range of 0-80°C is also presented. This laboratory has been investigating the thermodynamic properties of aqueous rare earth salt solutions for some years, and as part of this study, precise thermal expansion data were needed. The dilatometric method of measurement chosen to obtain the thermal expansion data required an accurate measurement of thermal expansions of the dilatometers themselves. To this end, water was initially chosen as the calibrating liquid as it was readily available in high purity, and accurate, consistent density data over the required temperature range of 5-80°C seemed to be available.The water density data of Chappuis (3) covering the temperature range of 0-42°C as represented by the Tilton and Taylor equation (12) are generally accepted as a standard in this country as well as by the International Bureau of Weights and Measures. Furthermore, these data have been extended to 80°C by Jones et al. ( 6) and Steckel and Szapiro (11), and to 85°C by Owen et al. (9). Unfortunately these sets of data differ by as much as 27 X 10~6 g/ml at 80°C which is approximately 10 times what we believe to be our allowable error for calibration purposes. Owen et al. attributed this difference to the use by Jones et al. of only a linear equation as opposed to a quadratic equation to represent the volumes of their dilatometers as a function of temperature. This criticism appeared reasonable, and thus the density data of Owen et al. which extended the Chappuis data to 85°C was assumed to be correct.Owen et al. had found that the expression, AV/At = a + b£av (1) in which iav is the mean temperature of the interval At, represented the volume expansions of their dilatometers over the temperature range of 5-85°C. As the borosilicate glass dilatometers used were similar in size and shape to the ones used in this research, it was expected Equation 1 would be obeyed in this research as well. However, when the densities of water determined by Chappuis and by Owen et al. were used as the standards for our data, the AV/At vs. £av plots obtained were not quite linear. This fact plus the disagreement between the data of ...

Volumetric properties of water, and solutions of sodium chloride and potassium chloride at temperatures fromT= 277.15 K toT= 343.15 K at molalities of (0.1, 0.5, and 1.0)mol·kg−1

“…where the temperature at the maximum density was T = 277.136 K. Gildseth et al (14) also modified the Tilton and Taylor equation by adding the exponential term (five adjustable parameters) to fit the densities of water from T = (278 to 353) K. The densities of water given in table 1 and represented by equation (1) agree with the high-accuracy densities given in the literature. The distinction between the quality of waters used in the experiments is probably less important when the temperature dependence, and the first and the second derivatives of density with respect to temperature are considered.…”

An Examination of the Ternary Methane + Carbon Dioxide + Water Phase Diagram using the SAFT-VR Approach

“…This model represents adequately the whole phase diagram, with a satisfactory quantitative agreement with experimental literature data. Figure 1 plots available vapour pressure experimental data for pure water [50][51][52][53][54][55][56][57][58] and CO 2 , [59][60][61][62][63][64] as well as data on the high pressure branch of the liquid vapour critical line 65,66 and three phase line, 15 showing remarkable quantitative agreement in all cases.…”

AFCI Safeguards Enhancement Study: Technology Development Roadmap

“…It is feasible to extend the on-line methodology to fuel reprocessing streams for the predictions of U and Pu. Equations have been derived using density, conductivity and temperature measurements for the determination of Pu, U, and nitric acid concentration within fuel reprocessing solutions [Clark 2002;Sakurai 1996;Gildseth 1972;Kumar 1998;Charrin 2000;Yamamoto 1988]. The derived equations correlating Pu concentration to density have included the effects of temperature, nitric acid, and in some cases, uranium [Gildseth 1972].…”

“…Equations have been derived using density, conductivity and temperature measurements for the determination of Pu, U, and nitric acid concentration within fuel reprocessing solutions [Clark 2002;Sakurai 1996;Gildseth 1972;Kumar 1998;Charrin 2000;Yamamoto 1988]. The derived equations correlating Pu concentration to density have included the effects of temperature, nitric acid, and in some cases, uranium [Gildseth 1972]. More than 700 composition and density data taken from technical literature were fit to the derived equation, yielding, for the Pu(IV)/U(VI)/HNO 3(aq) system, an equation that is valid for all combinations of Pu(IV), U(VI), and HNO 3 in water with a 0.75% relative uncertainty.…”