1.  Consider an aqueous solution that is saturated with nitrogen gas and sugar (glucose) at 80 °C. You may recall from lecture that as for most non-ionic solutes, K_s for glucose increases with increasing temperature.  For N₂, as for most gases, K_H decreases with increasing temperature.  Predict what happens when:

A.  More sugar is added to the solution at 80 °C.

B.  The solution at 80 °C is heated to 95 °C.

C.  The solution is cooled to room temperature.

2.  Using the K_spdata below, predict the products for the following reaction:

Ca²⁺(aq) +  NO₃^–(aq) +  K⁺(aq) +  F^–(aq) -> ???

K_sp Ca(NO₃)₂ = 1.6 x 10^-3 K_sp CaF₂ = 3.5 x 10^-11

K_sp KNO₃ = 1.3 x 10⁶  K_sp KF = 8.7 x 10⁵

3. You are provided with an aqueous solution containing 0.050 M Mg²⁺ and 0.050 M Cu²⁺ ions and are asked to try to separate them. What concentration of OH^– is needed to begin precipitation of each cation? K_sp = 1.8 x 10^-11 for Mg(OH)₂; K_sp = 4.8 x 10^-20 for Cu(OH)₂. 

4. Calculate how many mL of a 0.1 M NaOH solution was added to a titration mixture of 100 mL of 0.1 M HCOOH (pK_a = 3.75) solution to reach a final pH of 5.1.

5. 50 mL of 0.03 M HCl solution was added to 100 mL of 0.10 M acetic acid solution (CH₃COOH, K_a = 1.8 x 10^-5). What is the pH of the mixture?

6. Consider again the previous problem: What fraction of the acetic acid is dissociated before and after the addition of the HCl solution?

7. Consider a solution of ammonia, NH₃. An equal volume of an ammonium chloride solution of the same concentration was added to the ammonia solution. How will this affect the pH of the ammonia solution? Explain your answer.

8. You have 1.0 L of a formic acid buffer that is 0.10 M in HCOOH and 0.050 M in HCOONa. The following substances were added to this buffer in three separate experiments: 1) 0.05 mol of HCl, 2) 0.05 mol of NaOH, 3) 0.05 mol of HCOONa. Which of the resulting solution(s) no longer function(s) as a buffer? Explain your answer.

9. What is the solubility of PbI₂(s) in a solution saturated with another sparingly soluble iodide salt relative to PbI₂(s) solubility in pure water? Explain your answer.

10. Consider a solution of CaCl₂ and Mg(NO₃)₂ in which the concentrations of both Mg²⁺ and Ca²⁺ are the same, 0.01. M.  Is it possible to separate Ca²⁺ from Mg²⁺ by selective precipitation of Mg(OH)₂? To be precise, is it possible to precipitate 99.99% of magnesium without precipitating any calcium as hydroxides? For the sake of simplicity, assume that the precipitation reactions do not result in any change of the volume of the reaction mixture. The K_sp values of the calcium and magnesium hydroxides are 6.5 x 10^-5 and 7.1 x 10^-12, respectively. Show your work.