Liquid Solution

Calculate the mass of solute dissolved in $1 \mathrm{dm}^3$ water has osmotic pressure 3.0 atm at 300 K [Molar mass of solute $=41 \mathrm{~g} \mathrm{~mol}^{-1}$, $\mathrm{R}=0.082 \mathrm{dm}^3 \mathrm{~atm} \mathrm{~K} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ ]