Ostwald coefficient

Physical key figure
Surname	Ostwald coefficient
Formula symbol	${\displaystyle L}$
dimension	dimensionless
definition	${\displaystyle L={\frac {V_{\mathrm {g} }}{V_{\mathrm {l} }}}}$
${\displaystyle V_{\mathrm {g} }}$ absorbed gas volume ${\displaystyle V_{\mathrm {l} }}$ pure volume of liquid
Named after	Wilhelm Ostwald
scope of application	Solubility of gases in liquids .

The Ostwald coefficient (after Wilhelm Ostwald , formula symbol L , sometimes also λ ) - often also called the solubility coefficient - is a key figure for the solubility of gases in liquids .

Determining equation

${\displaystyle L={\frac {V_{\mathrm {g} }}{V_{\mathrm {l} }}}}$

The Ostwald coefficient is originally defined as the ratio of the volume of gas absorbed to the volume of the absorbing (pure) liquid. In addition to this definition, three more can be found in the relevant literature. Both volumes are to be determined at the same temperature. If the gas behaves ideally and Henry's law applies, i.e. only small solubilities are considered, the Ostwald coefficient is independent of the partial pressure of the gas. For real applications, however, it is necessary to specify temperature and total pressure.

Sample values ​​for selected substances

gas	liquid	Ostwald coefficient	Temperature in K	P total in kPa	Mole fraction x (calculated)	source
argon	water	0.0561	274.15	101.325	0.00004443
argon	water	0.0257	323.15	101.325	0.000015527
oxygen	toluene	0.1280	293.15	101.325	0.0005491
hydrogen	Ethanol	0.0894	298.15	101.325	0.00019717

See also

• Henry coefficient
• Bunsen absorption coefficient

literature

1. ↑ ^{a b} Rubin Battino: The Ostwald Coefficient of Gas Solubility. In: Fluid Phase Equilibria. Vol. 15, No. 3, 1984, ISSN  0378-3812 , pp. 231-240.
2. ↑ H. Lawrence Clever, Colin L. Young (Ed.): Methane (= Solubility Data Series. Vol. 27/28). Pergamon Press, Oxford et al. 1987, ISBN 0-08-029200-3 .
3. ^ Molenbruch des Gases, data from Dortmund database .
4. ↑ ^{a b} Tadeusz Estreicher : The solubility ratios of argon and helium in water. In: Journal for physical chemistry, stoichiometry and kinship theory . Vol. 31, 1899, pp. 176-187.
5. ↑ M. Резниковский, 3. Тарасова, Б. Догадкин: Растворимость кислорода в некоторых органических жидкостях. In: Журнал общей химии. Vol. 20, No. 1, 1950, ISSN  0044-460X , pp. 63-67.
   English translation: M. Reznikovskii, Z. Tarasova, B. Dogadkin: Oxygen Solubility in Some Organic Liquids. In: The Journal of General Chemistry of the USSR. Vol. 20, No. 1, 1950, ISSN  0022-1279 , pp. 67-71.
6. ^ Gerhard Just : Solubility of gases in organic solvents. In: Journal for physical chemistry, stoichiometry and kinship theory. Vol. 37, 1901, pp. 342-367.