What is something that would lower the freezing point of water to -3.7 degrees C if one mole were placed in 1000g of water?
I'm not sure how to go about this, I appreciate your help. (:
The problem wants you to calculate the molality of a solution and use that to know the kind of substance it must be. That is
delta T = i*Kb*m but you know m = 1 because there is 1 mol/kg solvent. If that is a covalent compound (meaning i = 1) how much will it lower the f.p. That will be
dT = i*Kf*m = 1*1.86*1 so dT -1.86 and that's the best you can do with 1 mol of a covalent compound. Therefore, I would use that to calculate i = van't hoff factor.
dT = i*K*m
i = dT/K*m = 3.7/1.86*2 so i = 1.98 which rounds to 2. That means you must have an ionic compound that gives you two particles when it ionizes. Can you think of some ionic compounds that will do that?