10.30 mg of O₂ is dissolved into a liter of sea water of density 1.03 g/ml. The concentration of O₂ in ppm is $\underline{ }$

$\mathrm{ppm}=\frac{\mathrm{Wt}. \mathrm{of} \mathrm{solute}\left(\mathrm{gm}\right)}{\mathrm{Wt}. \mathrm{of} \mathrm{solution}\left(\mathrm{gm}\right)}\times {10}^6$
Using the density of the solution and its volume (1 L=1000 mL=1000 cm³), the weight of the solution can be calculated.
W_solution=1.03×1000=1030 g
Thus, $\mathrm{ppM}=\frac{10.3\times {10}^{-3}}{1030}\times {10}^6=10\mathrm{ppm}$