GASES, LIQUIDS, AND SOLIDS Using the Kf and Kb equations - 1 A solution is A certain substance X has a normal freezing point of 3.6 C and a molal freezing point depression constant K,=5.61 C-kg-mol prepared by dissolving some urea ((NH2), CO) in 500. g of X. This solution freezes at -7.4 C. Calculate the mass of urea that was dissolved. Be sure your answer has the correct number of significant digits. 0 g x10