7.A student carried out a fractional distillation of an unknown binary (2-component) mixture from a 50 mL pot solution. Based on the plot below, and assuming no azeotropes, what percent by volume was the solution in the lower boiling point component?

3. The vapor pressure over a solution of urea (CH4N₂O) is 291.2 mm Hg (PA). The vapor pressure of pure water at the same temperature is 355.1 mm Hg (PºA). Calculate the mole fraction of urea in the solution. [See above for MM(urea)]

When 0.253 g of benzoic acid, C6H5COOH, is dissolved in 12.45 g of cyclohexanol, C6H11OH, thefreezing point of cyclohexanol is lowered by 6.55oC. What is the molal freezing point depressionconstant, Kf, for this solvent? Show all calculations.

An antifreeze solution is prepared by mixing 1.00 L of water and 946 mL of ethylene glycol, C,H,O2 (molar mass = 62.07 g/mol). Calculate: (a) the mass percent of ethylene glycol in the mixture; (b) the mole fraction of ethylene glycol in the solution, and (c) the molality of ethylene glycol in the solution. (d) Determine the freezing point and boiling point of the solution. (Assume density of water = 1.00 g/mL; Kf= 1.86°C/m; K = 0.512°C/m; density of EG = 1.114 g/mL)