AP Chemistry Solubility Questions: Test Your Knowledge

🧪 Quick Study Guide

• ⚖️ Solubility is the ability of a substance (solute) to dissolve in a solvent.
• 🌡️ Temperature affects solubility; generally, solubility of solids in water increases with temperature.
• 💧 The solubility product constant, $K_{sp}$, represents the equilibrium constant for the dissolution of a solid in an aqueous solution.
• 📝 A small $K_{sp}$ value indicates low solubility.
• 📈 The ion product, $Q$, is used to predict if a precipitate will form: $Q < K_{sp}$ (no precipitate), $Q > K_{sp}$ (precipitate forms), $Q = K_{sp}$ (equilibrium).
• ➕ Common ion effect: The solubility of a salt decreases when a common ion is added to the solution.
• 🧮 Molar solubility is the number of moles of solute that dissolve in one liter of a saturated solution.

Practice Quiz

1. Which of the following salts is the least soluble in water, given their respective $K_{sp}$ values?
   1. $AgCl$, $K_{sp} = 1.8 \times 10^{-10}$
   2. $PbCl_2$, $K_{sp} = 1.6 \times 10^{-5}$
   3. $AgBr$, $K_{sp} = 5.0 \times 10^{-13}$
   4. $CaF_2$, $K_{sp} = 3.9 \times 10^{-11}$
2. The solubility of $Mg(OH)_2$ in water is $1.4 \times 10^{-4}$ M. What is the $K_{sp}$ for $Mg(OH)_2$?
   1. $1.4 \times 10^{-4}$
   2. $1.96 \times 10^{-8}$
   3. $7.84 \times 10^{-12}$
   4. $1.1 \times 10^{-11}$
3. Adding which of the following to a saturated solution of $AgCl$ will decrease the solubility of $AgCl$?
   1. $NaCl$
   2. $KNO_3$
   3. $H_2O$
   4. $NH_3$
4. The $K_{sp}$ for $Cu(OH)_2$ is $2.2 \times 10^{-20}$. What is the molar solubility of $Cu(OH)_2$ in water?
   1. $2.2 \times 10^{-20}$ M
   2. $1.7 \times 10^{-7}$ M
   3. $2.8 \times 10^{-7}$ M
   4. $8.1 \times 10^{-11}$ M
5. Will a precipitate of $PbCl_2$ form when 0.010 M $Pb(NO_3)_2$ is mixed with 0.010 M $NaCl$? ($K_{sp}$ for $PbCl_2 = 1.6 \times 10^{-5}$)
   1. Yes, because $Q > K_{sp}$
   2. No, because $Q < K_{sp}$
   3. Yes, because $Q < K_{sp}$
   4. No, because $Q > K_{sp}$
6. What is the molar solubility of $AgCl$ in a 0.1 M $NaCl$ solution? ($K_{sp}$ for $AgCl = 1.8 \times 10^{-10}$)
   1. $1.8 \times 10^{-9}$ M
   2. $1.8 \times 10^{-10}$ M
   3. $1.3 \times 10^{-5}$ M
   4. $1.3 \times 10^{-10}$ M
7. Which of the following statements is true regarding the solubility of ionic compounds?
   1. The solubility of all ionic compounds increases with increasing temperature.
   2. The solubility of all ionic compounds decreases with increasing temperature.
   3. The solubility of ionic compounds is not affected by temperature.
   4. The solubility of some ionic compounds increases with increasing temperature, while others decrease.