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- Examine the structures of phenol and naphthol shown here and explain why phenol is so much more soluble in water at 25 °C (87 g/L) compared to naphthol (0.74 g/L).
문제 1
- Use Henry’s Law to determine the molar solubility of helium at a pressure of 1.0 atm and 25 °C.
문제 5
- You can purchase hydrochloric acid in a concentrated form that is 37.0% HCl by mass and that has a density of 1.20 g>mL. Describe exactly how to prepare 2.85 L of 0.500 M HCl from the concentrated solution.
문제 6
- Calculate the freezing point and boiling point of a solution containing 7.55 g of ethylene glycol (C2H6O2) in 85.7 mL of ethanol. Ethanol has a density of 0.789 g/cm³.
문제 8
- What is the required concentration (in percent by mass) for an aqueous ethylene glycol (C2H6O2) solution to have a boiling point of 104.0 °C?
문제 9
- What is the boiling point of an aqueous solution with a vapor pressure of 20.5 torr at 25 °C? (Assume a nonvolatile solute.)
문제 11
문제 29
Pick an appropriate solvent from Table 13.3 to dissolve each substance. State the kind of intermolecular forces that would occur between the solute and solvent in each case. a. motor oil (nonpolar) b. ethanol (polar, contains an OH group) c. lard (nonpolar) d. potassium chloride (ionic)
문제 30a,c,d
Pick an appropriate solvent from Table 13.3 to dissolve each substance. State the kind of intermolecular forces that would occur between the solute and solvent in each case. a. isopropyl alcohol (polar, contains an OH group) c. vegetable oil (nonpolar) d. sodium nitrate (ionic)
문제 30b
Pick an appropriate solvent from Table 13.3 to dissolve each substance. State the kind of intermolecular forces that would occur between the solute and solvent in each case. b. sodium chloride (ionic)
문제 31
Which molecule would you expect to be more soluble in water: CH3CH2CH2OH or HOCH2CH2CH2OH?
- Which molecule would you expect to be more soluble in water: CCl4 or CH2Cl2?
문제 32
문제 33
For each compound, would you expect greater solubility in water or in hexane? Indicate the kinds of intermolecular forces that occur between the solute and the solvent in which the molecule is most soluble. a. glucose
문제 34
For each compound, would you expect greater solubility in water or in hexane? Indicate the kinds of intermolecular forces that would occur between the solute and the solvent in which the molecule is most soluble. d. ethylene glycol
- When ammonium chloride (NH4Cl) is dissolved in water, the solution becomes colder: a. Is the dissolution of ammonium chloride endothermic or exothermic? b. What can you conclude about the relative magnitudes of the lattice energy of ammonium chloride and its heat of hydration? c. Sketch a qualitative energy diagram similar to Figure 13.7 for the dissolution of NH4Cl. d. Why does the solution form? What drives the process?
문제 35
문제 36a
When lithium iodide (LiI) is dissolved in water, the solution becomes hotter. a. Is the dissolution of lithium iodide endothermic or exothermic?
문제 36b
When lithium iodide (LiI) is dissolved in water, the solution becomes hotter. b. What can you conclude about the relative magnitudes of the lattice energy of lithium iodide and its heat of hydration?
문제 36c
When lithium iodide (LiI) is dissolved in water, the solution becomes hotter. c. Sketch a qualitative energy diagram similar to Figure 13.7 for the dissolution of LiI.
문제 36d
When lithium iodide (LiI) is dissolved in water, the solution becomes hotter. d. Why does the solution form? What drives the process?
문제 37
Silver nitrate has a lattice energy of -820 kJ/mol and a heat of solution of 22.6 kJ/mol. Calculate the heat of hydration for silver nitrate.
문제 38
Use the data to calculate the heats of hydration of lithium chloride and sodium chloride. Which of the two cations, lithium or sodium, has stronger ion–dipole interactions with water? Why?
- Lithium iodide has a lattice energy of -7.3 * 10^2 kJ/mol and a heat of hydration of -793 kJ/mol. Find the heat of solution for lithium iodide and determine how much heat is evolved or absorbed when 15.0 g of lithium iodide completely dissolves in water.
문제 39
문제 40
Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate has to dissolve in water to absorb 1.00⨉102 kJ of heat?
문제 41
A solution contains 25 g of NaCl per 100.0 g of water at 25 °C. Is the solution unsaturated, saturated, or supersaturated? (Use Figure 13.11.)
문제 42
A solution contains 32 g of KNO3 per 100.0 g of water at 25 °C. Is the solution unsaturated, saturated, or supersaturated? (Use Figure 13.11.)
문제 43
A KNO3 solution containing 45 g of KNO3 per 100.0 g of water is cooled from 40 °C to 0 °C. What happens during cooling? (Use Figure 13.11.)
- A KCl solution containing 42 g of KCl per 100.0 g of water is cooled from 60 °C to 0 °C. What happens during cooling? (Use Figure 13.11.)
문제 44
- Why do some laboratory procedures involving oxygen-sensitive reactants or products call for using water that has been boiled and then cooled?
문제 45
- Why do fish die when placed in a tank filled with water that has been boiled and then cooled?
문제 46
- Scuba divers breathing air at increased pressure can suffer from nitrogen narcosis—a condition resembling drunkenness—when the partial pressure of nitrogen exceeds about 4 atm. What property of gas-water solutions causes this to happen? How can a diver reverse this effect?
문제 47
문제 48
Scuba divers breathing air at increased pressure can suffer from oxygen toxicity—too much oxygen in their bloodstream— when the partial pressure of oxygen exceeds about 1.4 atm. What happens to the amount of oxygen in a diver's bloodstream when he or she breathes oxygen at elevated pressures? How can this be reversed?