Henry's law
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de:Henry-Gesetz In chemistry, Henry's law is one of the gas laws. It states that the mass of a gas that dissolves in a definite volume of liquid is directly proportional to the pressure of the gas provided the gas does not react with the solvent. William Henry first formulated the law in 1801.
A formula for Henry's Law is:
- <math> e^P = e^{kC} <math>
where P is the partial pressure of the gaseous solute above the solution, C is the concentration of the gas in mol/L and k is the Henry's Law constant, which has the units L*atm/mol.
Taking the natural logarithm of the formula, gives us the more commonly used formula:
- <math> P = kC <math>
This version is used to showcase the effectiveness of the law for dilute solutions of gases that don't react with the solvent. Some values for k include:
- O2 : 4.34×104 atm/mol
- CO2 : 1.64×103 atm/mol
- H2 : 7.04×104 atm/mol
when these gases are dissolved in water at 299 kelvin. Note that the solubility coefficient varies with solvent and temperature.