OOO QUESTION 14 Select the best representation for an aqueous potassium iodide (KI) solution key potassium ion iodide ion a. box a box b box c box d box e b. C. d. e.

The dispersed phase of a certain colloidal dispersion consists of spheres of diameter 1.0 102 nm. (a) What are the volume (V=43r2) and surface area (A = r2) of each sphere? (b) How many spheres are required to give a total volume of 1.0 cm3? What is the total surface area of these spheres in square meters?

Caffeine is made up of 49.5% C, 5.2% H, 16.5% O, and 28.9% N. A solution made up of 8.25 g of caffeine and 100.0 mL of benzene (d=0.877g/mL) freezes at 3.03C. Pure benzene (k f =5.10C/m) freezes at 5.500C. What are the simplest and molecular formulas for caffeine?

6-99 A concentrated nitric acid solution contains 35% HNO3. How would we prepare 300. mL of 4.5% solution?

Solutions of hydrogen in palladium may be formed by exposing Pd metal to H2 gas. The concentration of hydrogen in the palladium depends on the pressure of H2 gas applied, but in a more complex fashion than can be described by Henry's law. Under certain conditions, 0.94 g of hydrogen gas is dissolved in 215 g of palladium metal (solution density = 10.8 g cm3). (a) Determine the molarity of this solution. (b) Determine the molality of this solution. (c) Determine the percent by mass of hydrogen atoms in this solution.

Sodium chloride (NaCl) is commonly used to melt ice on roads during the winter. Calcium chloride (CaCl2) is sometimes used for this purpose too. Let us compare the effectiveness of equal masses of these two compounds in lowering the freezing point of water, by calculating the freezing point depression of solutions containing 200. g of each salt in 1.00 kg of water. (An advantage of CaCl2 is that it acts more quickly because it is hygroscopic, that is. it absorbs moisture from the air to give a solution and begin the process. A disadvantage is that this compound is more costly.)

How do colloids differ from solutions with regard to dispersed particle size and homogeneity?

6-39 Assuming that the appropriate volumetric flasks are available, describe how we would make these solutions: (a) 175 mL of a 1.14 M solution of NH4Br in water (b) 1.35 L of a 0.825 M solution of Nal in water (c) 330 mL of a 0.16 M solution of ethanol, C2H6O, in water

When KNO3 is dissolved in water, the resulting solution is significantly colder than the water was originally. (a) Is the dissolution of KNO3 an endothermic or an exothermic process? (b) What conclusions can you draw about the intermolecular attractions involved in the process? (c) Is the resulting solution an ideal solution?

6-38 Describe how we would prepare 250 mL of 0.10 M NaOH from solid NaOH and water.