3. The freezing point of biphenyl (molar mass 154 g/mole) is 71.0°C. When 1.240 g of benzophenone (molar mass 182 g/mole) is added to 9.52 g of biphenyl the solution is found to freeze at 14.3°C. Calculate the freezing point depression constant, K for biphenyl.

The freezing point of 0.109 m aqueous formic acid is 0.210C. Formic acid, HCHO2, is partially dissociated according to the equation HCHO2(aq)H+(aq)+CHO2(aq) Calculate the percentage of HCHO2 molecules that are dissociated, assuming the equation for the freezing-point depression holds for the total concentration of molecules and ions in the solution.

The freezing point of p-dichlorobenzene is 53.1 C, and its Kf is 7.10 C kg/mol. A solution of 1.52 g of the drug sulfanilamide in 10.0 g p-dichlorobenzene freezes at 46.7 C. Calculate the molar mass of sulfanilamide.

Butane, C4H10, has been suggested as the refrigerant in household compressors such as those found in air conditioners. (a) To what extent is butane soluble in water? Calculate the butane concentration in water if the pressure of the gas is 0.21 atm. (kH = 0.0011 mol/kgbar at 25 C) (b) If the pressure of butane is increased to 1.0 atm, does the butane concentration increase or decrease?