The density of a solution prepared by dissolving 120 g of urea (mol. Mass = 60 u) in 1000 g of water is 1.15 g/mL. The molarity if this solution is 

 Total mass of solution = 1000 g water + 120 g urea = 1120 g

Density of solution = 1.15 g/mL

Thus, volume of solution = $\frac{\mathrm{mass}}{\mathrm{density}}=\frac{1120\mathrm{g}}{1.15\mathrm{g}/\mathrm{mL}}$

                                        = 973.91 mL = 0.974 L

Moles of solute = $\frac{120}{60}=2\mathrm{mol}$

$\begin{array}{l}\mathrm{Molarity}=\frac{\mathrm{moles}\mathrm{of}\mathrm{solute}}{\mathrm{volume}\left(\mathrm{L}\right)\mathrm{of}\mathrm{solution}}\\ =\frac{2\mathrm{mol}}{0.974\mathrm{L}}=2.05\mathrm{mol}{\mathrm{L}}^{-1}\end{array}$