Need help answering Pre-lab questions 1-5

You should be able to answer the following questions before coming to lab to perform the experiment. Please be sure to show all work and to use the proper number of significant figures. 1. Write the equation that relates the freezing-point depression and the molal concentration of the solute, and define each term. 2. Explain the difference between molarity and molality. Give the units for each. 3. Calculate the freezing point in C of a solution prepared by dissolving 21.5g of Zn(NO3)2 in 250g of water. Assume that the Zn(NO3)2 dissociates completely. 4. Calculate the molality of a solution containing 8.251g of naphthalene (molar mass =128.17gmol1 ) dissolved in 250g of cyclohexane. 5. A solution containing 0.652g of an unknown solid dissolved in 50.0 g of benzene is found to have a freezing point of 4.9C. What is the molar mass of the unknown? Assume that the van't Hoff factor equals 1