Question

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

I know I already posted this question but I couldn't find my original post so that I could have my answer checked.

I did 62.07g = mol / 500g = 0.124

0.124mol X 1000g = 124g/mol

Is this correct?

Answer 1

No. You have the right answer but you didn't work it right. It just happens that the numbers worked for you. Any other set of numbers (It works because m =1) and you would not get the right answer. You work it this way.
delta T = Kf*m
You know freezing point, calculate delta T from that. You know Kf. Substitute and solve for m = molality.
Then m = moles/kg solvent.
You know m and kg solvent, solve for mole.

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