Most fish need at least 4.00 ppm dissolved O2 for survival.

Question

(a) What is this concentration in M (assume the density of the
solution is 1.00 g/mL)?
(b) What partial pressure of O2 above the water is needed to
obtain this concentration at 10. °C? The Henry’s law
constant for O2 at this temperature is 1.71 ×10-3 mol/L-atm

I'm not really sure how to even start :/

Answer 1

a.
4 ppm = 4 mg/L.
mols O2 = grams/molar mass and since that many mols are in 1 L that is the M.
b.
concn(M) = K*P
You know M from part a and you K from the problem, solve for partial pressure of the gas.

Answer 2

Thank you so much for your help!