Question

When 0.855 g of this solid was dissolved in 7.50 g of napthalene, the solution had a freezing point of 78.0° C. The pure solvent freezes at 80.0° C; its molal freezing point constant is 6.8° C/m. What is the molecular formula of the compound?

Answer 1

delta T = Kf*molality
Solve for molality

molality = moles/kg solvent
Solve for moles.

moles = grams/molar mass
Solve for molar mass.