Question

A solution was made by dissolving 62.07 grams of a compound in 500g of water. The compound was not ionic. The freezing point of the solution was measured and found to be -1.86 degrees celsius. Using the Kf value in your textbook, the molar mass of this conpound can be calculated to be?

I am not sure what Kf value they are referring to for me to find. Would I use the freezing point equation for this?

Answer 1

Yes, delta T = Kf*m
Solve for m

Then m = mols/kg solvent
You know m and kg solvent, solve for mol.

Then mol = grams/molar mass
You know mol and grams, solve for molar mass.

Answer 2

so delta T would be 1.86 but Im not sure what Kf would be?

Answer 3

Kf = Kf = Kf. What have you been using for Kf for water? Isn't that 1.86. I know what's confusing you. delta T = 1.86 and Kf is 1.86. Just plug it into the equations and the math will work out.