Gas SolubilitiesHenry’s Law: [A]equilibrium = SA · pA

“the partial pressure of a gas above a liquid is proportional to theconcentration in liquid under thermodynamic equilibrium”

Bunsen coefficient (β)“the volume of a gas at STP (0°C and 1atm) that dissolves in one unit volume of solution at temperature T with a total pressure of 1 atm and a fugacity (chemical potential--tendency of a gas toprefer one phase of another, escape or expand) 1 atm”

Solubility function (F)

The Bunsen coefficient

fugacity

corrects partial pressure for the non-ideal behavior of gas

Combining the Bunsen coeff. with solubility

Dropped, for near-ideal behavior

Saturation water vapor

Concentration of a gas in seawater is determined by its partial pressure in moist air. The relationship between the partial pressures of moist and dry air.

Solubility function (FA)

Solubilities decrease with increased temperature

Differences between gases can be caused by molecular weight and other factors such as molecular interaction between the gas and water.

For single element gases, more soluble with increased molecular weight.