AP Chem. 3
posted by Kathryn .
A 1.80 g sample of a large boimolecule was dissolved in 21.0 g of carbon tetrachloride. The boiling point of this solution was determined to be 77.85°C. Calculate the molar mass of the biomolecule. For carbon tetrachloride, the boiling point constant is 5.03°C·kg/mol, and the boiling point of pure carbon tetrachloride is 76.50°C.
delta T = kb*molality
You know delta T and Kb.
Solve for m
molality = moles unknown/kg solvent
Solve for moles unknown.
moles = grams/molar mass
You have moles unknown and grams unknown,
solve for molar mass of unknown.