Formula and The Henry's Law Constant
Henry's law can be put into mathematical terms (at constant temperature) as
where p is the partial pressure of the solute in the gas above the solution, c is the concentration of the solute and kH is a constant with the dimensions of pressure divided by concentration. The constant, known as the Henry's law constant, depends on the solute, the solvent and the temperature.
Some values for kH for gases dissolved in water at 298 K include:
- oxygen (O2) : 769.2 L·atm/mol
- carbon dioxide (CO2) : 29.41 L·atm/mol
- hydrogen (H2) : 1282.1 L·atm/mol
There are other forms of Henry's Law, each of which defines the constant kH differently and requires different dimensional units. In particular, the "concentration" of the solute in solution may also be expressed as a mole fraction or as a molality.
Read more about this topic: Henry's Law
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