This Demonstration calculates the mole fractions of gases dissolved in water. Check "set temperature" to display mole fractions in a bar graph and set the temperature with a slider. Uncheck "set temperature" to plot mole fractions as a function of temperature and hover the cursor over a curve to see which gas it corresponds to. Only the gases whose boxes are checked are displayed. The mole fractions are calculated independently for each gas at the gas pressure (set with a slider).
Henry's constant varies with temperature, as given by:
where is in bar; , , and are constants specific to each species; and is temperature (K).
Henry's law is used to calculate the mole fraction of a species dissolved in water:
where is the partial pressure (bar).
The screencast video at  explains how to use this Demonstration.
 B. E. Poling, G. H. Thomson, D. G. Friend, R. L. Rowley and W. V. Wilding, "Physical and Chemical Data," Perry's Chemical Engineers' Handbook (D. W. Green and R. H. Perry, eds.), 8th ed., New York: McGraw-Hill, 2008.