1. An aqueous solution containing 35.0% by mass of an unknown covalent compund in water was found to have a freezing point of -3.5 deg C. Calculate the molar mass of the unknown compund.
2. A 11.6 M aqueaous solution of ethylene glycol (C2H6O2) has the capability of lowering the freezing point of water to -45 deg C! The density of the solution is 1.09 g/mL and the molar mass of ethylene glycol is 62.07 g/mol.
a) what is the molality of ethylene glycol solution?
b) what is the mole fraction of the ethylene glycol solution?
3. A mixture of benzene and methylbenzene has a normal boiling point of 398K. Given the information below:
Substance Vapor Pressure at 398K Molar Mass
Benzene 1520 torr 78.11 g/mole
Methylbenzene 570 torr 92.14 g/mole
a) what is the mole fraction of benzene in the liquid (solution)?
b) what is the mole fraction of benzene in the vapor?