Gas Solubilities Henry’s Law: [A]equilibrium = SA · pA “the partial pressure of a gas above a liquid is proportional to the concentration 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 to prefer 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

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. Saturation water vapor 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.