Chapter 13 Homework Problems

Notes: 1.) Hand in your answers/work on a separate sheet (not a printout of these problems). 2.) You can receive partial credit even if your answer is incorrect, but only if you show your work! 3.) Be sure to include units (amu, g, mL, etc.) on any answers that need them. This is worth points! 4.) Be sure to use the correct number of significant figures in your answers. This is worth points too!

1. Tell what kinds of intermolecular forces could occur between the following pairs of solute and solvent, and place the list in order from weakest to strongest solute-solvent attraction. Some pairs may experience more than one type of force.

a. water dissolved in ammonia b. NO dissolved in H2S c. CO2 dissolved in ammonia d. Mg(NO3)2 dissolved in water

2. At sea level, the partial pressure of O2 is 0.21 atm. However, the Dead Sea is not at sea level -- it’s at a much lower altitude, where the atmospheric pressure is 806 mmHg and the temperature is 20˚C. Use Henry’s Law and Table 13.2 to calculate the molar concentration of O2 in the Dead Sea.

3. Suppose we make a solution by dissolving 42.5 g of I2 in 1.50 mol of CCl4.

a. What is the molality of this solution? b. Suppose we wanted to use our 42.5 g of I2 to make a 0.500 m solution. What volume of CCl4 would we need? The density of CCl4 is 1.589 g/mL.

4. We dissolve 200.0 g of NaCl in 684.5 g of water and find that the density of the solution is 1.15 g/mL. Calculate:

a. The % by mass of NaCl b. The mole fraction of NaCl c. The molarity of NaCl d. The molality of NaCl

5. Calculate the number of moles of solute in each solution.

a. A solution of Br2 dissolved in 50.0 g of