Vitamin K (a non-electrolyte) is involved in the blood clotting mechanism. When 0.510 g is dissolved in 9.999 g of camphor (C10H16O), the freezing point is lowered by 4.50 oC. Calculate the molecular weight of Vitamin K.

Kf C10H16O = 40.0 oC/m

Freezing Point Camphor = 179.50 oC

Question

Vitamin K (a non-electrolyte) is involved in the blood clotting mechanism. When 0.510 g is dissolved in 9.999 g of camphor (C10H16O), the freezing point is lowered by 4.50 oC. Calculate the molecular weight of Vitamin K.

Kf C10H16O = 40.0 oC/m

Freezing Point Camphor = 179.50 oC

jfraser · Answer

What's the equation for a change in freezing point?

parj95 · Answer

(Delta) Tf = Kf * molality

parj95 · Answer

@JFraser

jfraser · Answer

what you've got is the new freezing point, but not the molality of the solution. You need to find the molality, then rearrange that answer to find the $moles$ of the solute.

The mass of solute divided by that answer is the molar mass of vitamin K