SDS Volume (2663)
Volume 62. Carbon Dioxide in Water and Aqueous Electrolyte Solutions, p None
Original Measurements
He, S.; Morse, J. W.; Geochim. Cosmochim. Acta 1993, 57, 3533-54.
Variables:
Room Temp:
273.15 - 363.15
$\pu{K}$
Pressure:
0.1032
$\pu{MPa}$
Molality (2):
m2/mol kg-1 = 0.1 - 6.0; m3/mol kg-1 = 0.01
mol/kg
Prepared by:
Method/Apparatus/Procedure:
Either pure $\ce{CO2}$ gas or $\ce{CO2}-\ce{N2}$ mixtures were used in the experiments to maintain a constant P($\ce{CO2}$). The $\ce{CO2}-\ce{N2}$ mixtures were made by pumping predetermined amounts of $\ce{CO2}$ and $\ce{N2}$ into a gas tank and their composition was verified by gas chromatography.
$\ce{CO2}$ or $\ce{CO2}-\ce{N2}$ gas mixtures were equilibrated with the aqueous solutions in a series of stirred water-jacketed reaction vessels with condensers. The gas was pre-moistured by first passing it through distilled water at the temperature of experiment. Fine bubbles were obtained by using gas-dispersion tubes. The bubbling rate was 90-95 mL/min.
The mole fraction of $\ce{CO2}$ in the $\ce{CO2}-\ce{N2}$ mixture was determined using a Hewlett Packard (5790A) gas chromatograph.
Source and Purity of Materials:
- Commercial; purity 99.9%
- (2,3) Source not mentioned. Analytical reagent-grade which met ACS specifications.
Vacuum-dried before use. - 18 MΩ water obtained from a Milli-Q Super-Q water system.
Estimated Errors:
Ambient temperature: δT/K = ±0.1
Mass concentration (m/v) (1): δm1/m1 = ±0.012
δγ1/γ1 = ±0.04
Components:
- Carbon dioxide, $\ce{ CO2 }$; [124-38-9] NIST WebBook
- Sodium chloride, $\ce{ NaCl }$; [7647-14-5] NIST WebBook
- Calcium sulphate, $\ce{ CaSO4 }$; [7778-18-9] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
m3, the molality of CaSO4, was 0.01 mol kg-1 in all measurements
| $T$ ($\pu{K}$) | m1 (mol/kg) | m2 (mol/kg) | ρ (g/cm3) | γ |
|---|---|---|---|---|
| 273.15 | 0.0745 | 0.1 | 1.0114 | 1.03 |
| 273.15 | 0.0667 | 0.5 | 1.0224 | 1.15 |
| 273.15 | 0.0590 | 1.0 | 1.0411 | 1.30 |
| 273.15 | 0.0401 | 2.0 | 1.0787 | 1.63 |
| 273.15 | 0.0318 | 4.0 | 1.1460 | 2.42 |
| 273.15 | 0.0226 | 6.0 | 1.2095 | 3.40 |
| 298.15 | 0.0310 | 0.1 | 1.0189 | 1.03 |
| 298.15 | 0.0285 | 0.5 | 1.0189 | 1.12 |
| 298.15 | 0.0266 | 1.0 | 1.0363 | 1.20 |
| 298.15 | 0.0215 | 2.0 | 1.0700 | 1.47 |
| 298.15 | 0.0138 | 4.0 | 1.1340 | 2.31 |
| 298.15 | 0.010 | 6.0 | 1.1974 | 3.20 |
| 323.15 | 0.0160 | 0.1 | 1.0081 | 1.02 |
| 323.15 | 0.0148 | 0.5 | 1.0081 | 1.10 |
| 323.15 | 0.0140 | 1.0 | 1.0262 | 1.16 |
| 323.15 | 0.0122 | 2.0 | 1.0608 | 1.33 |
| 323.15 | 9.1 x 10-3 | 4.0 | 1.1240 | 1.79 |
| 323.15 | 6.8 x 10-3 | 6.0 | 1.1824 | 2.40 |
| 348.15 | 8.1 x 10-3 | 0.1 | 0.9795 | 1.02 |
| 348.15 | 7.9 x 10-3 | 0.5 | 0.9795 | 1.05 |
| 348.15 | 7.6 x 10-3 | 1.0 | 1.0120 | 1.07 |
| 348.15 | 7.2 x 10-3 | 2.0 | 1.0463 | 1.15 |
| 348.15 | 6.0 x 10-3 | 4.0 | 1.1090 | 1.37 |
| 348.15 | 5.6 x 10-3 | 6.0 | 1.1638 | 1.48 |
| 363.15 | 3.4 x 10-3 | 0.1 | 0.9624 | 1.03 |
| 363.15 | 3.3 x 10-3 | 0.5 | 0.9624 | 1.05 |
| 363.15 | 3.2 x 10-3 | 1.0 | 1.0028 | 1.08 |
| 363.15 | 3.0 x 10-3 | 2.0 | 1.0373 | 1.15 |
| 363.15 | 2.7 x 10-3 | 4.0 | 1.1002 | 1.27 |
| 363.15 | 2.5 x 10-3 | 6.0 | 1.1559 | 1.41 |
(a) Calculated by compiler
(b) m2 = molality of NaCl
(c) ρ = density of solvent
(d) p1 = partial pressure of CO2
(e) m1 = molality of CO2
(f) γ1 = activity coefficient of CO2
