Here is the question I have. I am asked to determine an approximate mass of sodium chloride needed to prepare a mixture containing 725.0 grams of ice slush at -10 degrees C. I have been working on this problem for four hours! My professor told me all I need is in the problem, but don't I need the Kf of NACL? I tried converting the 725 g to kg then to mol, but I needed the molality so that led nowhere. I tried Tf (solvent)- Tf(solution) but I don't know what to do with an anser I would get, which I can't cuz I don't know the mass of the bleepy bleep bleep solute!!!!!!