Posted by Sara on .
The solubility of nitrogen in water is 6.9 x 10^4 at exactly 1 atm pressure. What is the solubility of nitrogen under .80 atmp pressure?
I don't know where to start with this problem, what formula do I use?

Chemistry 
DrBob222,
Henry's Law.
p = kcC
p in atm. C in mols/L. You have no units in your post for 6.9E4.