posted by Sarah .
The Henry's Law constant for O2 in water is 1.28 x 10 ^ -3 M/atm. How many grams of O2 will dissolve in a 12 L fish tank on a day when atm is .977 and air is 18% O2?
I looked on the net at this site to see the formula you must be using for Henry's Law (many different versions in use). You can read more about it here.
You must be using c = pk; therefore,
c = (0.18*0.977)*1.28E-3
c = 2.25E-4 M. Convert that to grams (g = moles x molar mass) for the mass O2 in 1L, convert that to 12L.