The Freezing Points of Aqueous Solutions. Ii. Potassium, Sodium and Lithium Nitrates

Abstract

the solutions are kept saturated with nitrogen at atmospheric pressure, the concentrations are determined from the conductance and the temperatures with a multiple-junction thermocouple.The method combines many of what seem to us the best features of previous methods with the following new features: the stirring is done by two low-friction valve pumps in each vessel combined with hand stirring of the ice; the thermocouples are constructed so as to give the smallest possible difference between the temperature of the solution and that of the thermal junctions; the thermocouples are calibrated against a platinum resistance thermometer under conditions as nearly as possible the same as those under which they are used.It is shown that the effect of dissolved gas is approximately proportional to the square of the salt concentration, and is much smaller than had previously been supposed. A method of smoothing and computing by use of deviation curves is also described.Cambridge, Massachusetts

Concentrated Solutions of Strong Electrolytes.

“…The next figures show as the deviations of the osmotic coefficients from this function plus a term linear in the ionic strength. Figure 3 gives up to 1 molal determined from freezing points for potassium nitrate (30), potassium chloride (31), and potassium acetate (32). It shows that this function is a convenient one from which to plot deviations, but that these deviations are much larger than the experimental errors.…”

Determination of Pitzer Parameters for 1‐1 Nitrate and 1‐2 Sulfate Solutions from Freezing Point Data

“…Experimental data points in the range of 0.07369–1.3514 mol kg −1 for NaNO 3 solutions 30, 0.06327–1.001 mol kg −1 for KNO 3 solutions 30, 0.2763–1.4035 mol kg −1 for NH 4 NO 3 solutions 31, and 0.2671–1.2141 mol kg −1 for (NH 4 ) 2 SO 4 31 solutions were used for parameter estimation. The following parameters were obtained: β 0 (NaNO 3 ) = –0.0561, β 0 (KNO 3 ) = –0.1316, β 0 (NH 4 NO 3 ) = –0.0410, β 0 ((NH 4 ) 2 SO 4 ) = 0.0138, β 1 (NaNO 3 ) = 0.1963, β 1 (KNO 3 ) = –0.0966, β 1 (NH 4 NO 3 ) = 0.0322, β 1 ((NH 4 ) 2 SO 4 ) = 0.3140, C ϕ (NaNO 3 ) = 0.0107, C ϕ (KNO 3 ) = 0.0035, C ϕ (NH 4 NO 3 ) = –0.002, C ϕ ((NH 4 ) 2 SO 4 ) = –0.0007, with standard deviations of 0.002, 0.001, 0.0004, and 0.001 for NaNO 3 , KNO 3 , NH 4 NO 3 , and (NH 4 ) 2 SO 4 solutions, respectively.…”

“…10) depicting the deviation between the observed and predicted FPD in NaNO 3 (○), KNO 3 (□), and NH 4 NO 3 (Δ) solutions as a function of molality m . The observed values were adopted from the literature 30, 31 and the predicted values were determined from Eq. 3, in which osmotic coefficients were calculated from Eq.…”

Activity and osmotic coefficients of dilute sodium chloride solutions at 273 K

“…where N is the number of the experimental points and where t(AT,) is defined by t(AT,) = A7,(observed) -A7,(predicted) (6) The residual standard deviation of the fit is s0, and s"= [S/(/V-2)]1/2 (7) To find the exact values of a* and h, which minimize S, a nonlinear function minimizar (fmins) available In pc-mauab (16) was used. To estimate the precision of a * and h, the jackknifing technique (see Appendix or ref 17) was used.…”