A solutionof 2.50g of a compound having the empirical formula C7H6O2 in 25.0g of benzene is observed to freeze at 4.3 degree C.Calculate the molar mass of the solute and its Molecular formula

1 answer

Look up normal freezing point benzene.
Look up freezing point constant for benzene (Kf = ?).
delta T = Kf*molality
Solve for molality.

molality = moles/kg solvent
Solve for moles

moles = grams/molar mass
Solve for molar mass.

Find the mass of the empirical formula.
(molar mass/empirical mass) = ?? and round to the nearest whole number and call that number n. The molecular formula is (empirical formula)n.