General Chemistry 111 Quiz Two Practice Problems

Use the tables of water vapor pressure at different temperatures, and various colligative properties in your textbook.

1) The Henrys Law constant for oxygen gas in water at 20 C is 1.3 x 10-3 mol/L atm and the minimum mass concentration of oxygen required for fish life is 4 mg/L. a) Assuming the density of the solution is 1.00 g/mL, what is this concentration of oxygen in ppm? b) What is the minimum partial pressure of O2 that would supply this concentration in water at 20 C?

2) Calculate the vapor pressure of a saturated aqueous MgF2 solution at 20 C (the solubility of MgF2 at 20 C is 8 mg/100 g water).

3) For the following ideal aqueous solutions, estimate the freezing point depression, boiling point elevation, and osmotic pressure of: a) 0.10 m C11H22O11 b) 0.22 m NaCl. For osmotic pressure, use the same concentrations in mol/L (M).