Solutions Questions

The density of a solution prepared by dissolving $120\text{g}$ of urea (mol. mass $=60\text{u}$) in $1000\text{g}$ of water is $1.15\text{g/mL}$. The molarity of this solution is:

$K_f$ for water is $1.86{\text{K kg mol}}^{-1}$. If your automobile radiator holds $1.0\text{kg}$ of water, how many grams of ethylene glycol (${\text{C}}_2{\text{H}}_6{\text{O}}_2$) must you add to get the freezing point of the solution lowered to $-2.8^{\circ }\text{C}$?