IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Carbon dioxide with Potassium nitrate and Water

Components:
   (1) Potassium nitrate; KNO3; [7757-79-1]  NIST Chemistry WebBook for detail
   (2) Carbon dioxide; CO2; [124-38-9]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Markham, A.A.; Kobe, K.A., J. Am. Chem. Soc. 1941, 63, 449-54.

Variables:
   Temperature = 273.35 K to 313.15 K
   Pressure = 273.35 K to 313.15 K
   Concentration = c₂/mol kg^-1 = 0 - 3

Prepared By:
   D.M. Mason

Experimental Remarks:

   The authors fitted their data to equations:

S_m/S_o = am₂ + 1/(1 + bm₂), as follows:

t/°C a                  b
0.2                  0.0350                  0.170
25                  0.0248                  0.088
40                  0.0343                  0.086

Experimental Data:   (Subscripts 1,2,3, ..., in column headings refer to components 1,2,3, ...)


t/°C	T/K	Keunen coefficient, S	S Note	α	α Note	Molality m₂ [mol/kg]
0.2	273.35	1.7025	b	1.7023	a	0.0
0.2	273.35	1.6740	b	1.6680	a	0.1
0.2	273.35	1.6584	b	1.6470	a	0.2
0.2	273.35	1.6012	b	1.5733	a	0.5
0.2	273.35	1.5142	b	1.4610	a	1
25	273.35	0.7587	b	0.7565	a	0.0
25	298.15	0.7552	b	0.7501	a	0.1
25	298.15	0.7500	b	0.7421	a	0.2
25	298.15	0.7345	b	0.7182	a	0.5
25	298.15	0.7156	b	0.6860	a	1
25	298.15	0.6834	b	0.6296	a	2
25	298.15	0.6568	b	0.5818	a	3
40	298.15	0.5173	b	0.5133	a	0.0
40	313.15	0.4937	b	0.4704	a	1
40	313.15	0.4776	b	0.4370	a	2
40	313.15	0.4642	b	0.4083	a	3

Notes:
   ^a  α = Bunsen coefficient [cm³ (STP) cm^-3 atm^-1].
   ^b  S= Kuenen coefficient [cm³ (STP) g^-1(H₂O) atm^-1].

Method/Apparatus/Procedure:
   The principle of the Ostwald method was used in which the gas is agitated with a measured quantity of gas-free liquid and the decrease in volume of solution-saturated gas is measured in a burette over mercury. The pressure was adjusted to yield one atmosphere partial pressure of carbon dioxide. The volume of gas was reduced to 0°C by the ideal gas law. Experiments were conducted to show that the agitation did not cause super-saturation.

Source and Purity of Materials:
   (1) Commercial cylinder, 99.8 % pure.
   (2) Analytical grade.
   (3) Distilled and degassed..

Estimated Errors:
   Solubility: δα/α, δS/S = ± 0.002 (authors).
   Temperature: δT/K = <± 0.1 at 0.2°C, ± 0.03 at other temperatures (authors)