posted by lw .
When a certain amount of MgF2 is added to water, the freezing point lowers by 3.5 oC. What was the molality of the magnesium fluoride? (Kf for water = 1.86 oC/m)
delta T = i*Kf*m
i = 3, you know the other values, solve for m. By he way, this must be a made up problem because MgF2 isn't that soluble in water. In fact, it is hardly soluble at all.