text: When the temperature of a system changes, the Henry constant also changes. The temperature dependence of equilibrium constants can generally be described with the van t Hoff equation, which also applies to Henrys law constants:
  where  is the enthalpy of dissolution. Note that the letter  in the symbol  refers to enthalpy and is not related to the letter  for Henrys law constants. This applies to the Henrys solubility ratio, ; for Henry's volatility ratio,, the sign of the right-hand side must be reversed. 
  Integrating the above equation and creating an expression based on  at the reference temperature  = 298.15 K yields:
  The van 't Hoff equation in this form is only valid for a limited temperature range in which  does not change much with temperature (around 20K of variations).
  The following table lists some temperature dependencies: 
  Solubility of permanent gases usually decreases with increasing temperature at around room temperature. However, for aqueous solutions, the Henrys law solubility constant for many species goes through a minimum. For most permanent gases, the minimum is below 120 °C. Often, the smaller the gas molecule (and the lower the gas solubility in water), the lower the temperature of the maximum of the Henrys law constant. Thus, the maximum is at about 30 °C for helium, 92 to 93 °C for argon, nitrogen and oxygen, and 114 °C for xenon.