Henry's law

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 formulated the formula in 1801.

A formula for Henry's Law is:

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:

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 atoms
• CO₂ : 1.64×10³ atoms
• H₂ : 7.04×10⁴ atoms

when these gases are dissolved in water at 299 Kelvins