1). Calculate the moles of urea you have. Calculate the moles of water you have (150 mL of water = 150 g).
Divide moles of water / (moles of water + moles of urea)
2) Molarity is moles of solute / kg of solvent. Calculate the moles of naphthalene in 5.25 g. Divide by the mass of water, 0.1 kg, that is the molality. Multiply by 5.12 deg C / m and subtract from 5.5 C
3) Calculate the mole fraction of water using the method in the first question. Multiply by the vapor pressure of pure water.
1). 0.932
2). 3.4
3). 31.20
