11/ The concentration of O2 in seawater is 1.68 x 10-4 M at 25.0 °C.

What is this concentration in ppm? (assume the density of sea water = 1.00 g/mL)






12/ Some lake water is found to contain 548. ppm of methyl mercury, Hg(CH3)2. What is the concentration of methyl mercury in mass percent?






13/ 1.921 g of an organic compound is dissolved in 48.92 g of water. The aqueous solution starts to freeze at -0.450°C. What is the molar mass of the organic compound (in g/mol)?
Kf for water = 1.86 °C/m






14/ What is the freezing point (in °C) of a solution of 29.77 g methyl salicylate, C8H8O3, dissolved in 747.5 g of benzene, C6H6? The freezing point for benzene is 5.50°C. Kf for benzene is 5.10 °C/m.






15/ A solution is prepared by dissolving 49.08 g of sucrose, C12H22O11, in 250.0 g of water at 25°C. What is the vapor pressure of the solution (in mmHg) if the vapor pressure of water at 25°C is 23.76 mm Hg?




16/ Choose the aqueous solution below with the lowest freezing point. 


a. 0.075 m sodium periodate solution


b. 0.075 m sodium nitrite solution


c. 0.075 m potassium fluoride solution


d. 0.075 m ammonium phosphate solution


e. 0.075 m potassium cyanide solution