At 25 degrees celcius and 1.0 atm, 0.25 g of gas dissolves in 1.00 L of water. What mass of the gas dissolves in 1.00 L of water at 25 degrees celcius and 3.0 atm?

Answer 1

I think this describes Henry's Law very well.
http://www.800mainstreet.com/9/0009-006-henry.html