Problem 84
How would you prepare 1.0 \(\mathrm{L}\) of an aqueous solution of sodium chloride having an osmotic pressure of 15 atm at \(22^{\circ} \mathrm{C} ?\) Assume sodium chloride exists as \(\mathrm{Na}^{+}\) and \(\mathrm{Cl}^{-}\) ions in solution.
Problem 85
Consider the following solutions: 0.010\(m \mathrm{Na}_{3} \mathrm{PO}_{4}\) in water 0.020 \(m \mathrm{CaBr}_{2}\) in water 0.020 \(m \mathrm{KCl}\) in water 0.020 \(m \mathrm{HF}\) in water \((\mathrm{HF} \text { is a weak acid.) }\) a. Assuming complete dissociation of the soluble salts, which solution(s) would have the same boiling point as 0.040 \(\mathrm{m} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) in water? \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) is a nonelectrolyte. b. Which solution would have the highest vapor pressure at \(28^{\circ} \mathrm{C} ?\) c. Which solution would have the largest freezing-point depression?
Problem 86
From the following: Pure water solution of \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}(m=0.01)\) in water solution of \(\mathrm{NaCl}(m=0.01)\) in water solution of \(\mathrm{CaCl}_{2}(m=0.01)\) in water Choose the one with the a. highest freezing point. b. lowest freezing point. c. highest boiling point. d. lowest boiling point. e. highest osmotic pressure.
Problem 87
Calculate the freezing point and the boiling point of each of the following solutions. (Assume complete dissociation.) a. 5.0 \(\mathrm{g} \mathrm{NaCl}\) in 25 \(\mathrm{g} \mathrm{H}_{2} \mathrm{O}\) b. 2.0 \(\mathrm{g} \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3}\) in 15 \(\mathrm{g} \mathrm{H}_{2} \mathrm{O}\)
Problem 88
A water desalination plant is set up near a salt marsh containing water that is 0.10\(M \mathrm{NaCl}\) . Calculate the minimum pressure that must be applied at \(20 .^{\circ} \mathrm{C}\) to purify the water by reverse osmosis. Assume NaCl is completely dissociated.
Problem 94
The freezing-point depression of a \(0.091-m\) solution of \(\mathrm{CsCl}\) is \(0.320^{\circ} \mathrm{C} .\) The freezing-point depression of a \(0.091-\mathrm{m}\) solution of \(\mathrm{CaCl}_{2}\) is \(0.440^{\circ} \mathrm{C} .\) In which solution does ion association appear to be greater? Explain.
Problem 96
A 0.500 -g sample of a compound is dissolved in enough water to form 100.0 mL of solution. This solution has an osmotic pressure of 2.50 atm at \(25^{\circ} \mathrm{C}\) . If each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?
Problem 97
The solubility of benzoic acid, is 0.34 \(\mathrm{g} / 100 \mathrm{mL}\) in water at \(25^{\circ} \mathrm{C}\) and 10.0 \(\mathrm{g} / 100 \mathrm{mL}\) in benzene \(\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)\) at \(25^{\circ} \mathrm{C} .\) Rationalize this solubility behavior. For a \(1.0-\mathrm{m}\) solution of benzoic acid in benzene, would the measured freezing point depression be equal to, greater than, or less than \(5.12^{\circ} \mathrm{C} ?\left(K_{\mathrm{f}}=5.12^{\circ} \mathrm{C} \cdot \mathrm{kg} / \mathrm{mol} \text { for benzene.) }\right.\)
Problem 98
Would benzoic acid be more or less soluble in a \(0.1-M \mathrm{NaOH}\) solution than it is in water?
Problem 99
What stabilizes a colloidal suspension? Explain why adding heat or adding an electrolyte can cause the suspended particles to settle out
