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- 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.
Problem 39
Problem 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?
Problem 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.)
Problem 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.)
Problem 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.)
Problem 44
- Why do some laboratory procedures involving oxygen-sensitive reactants or products call for using water that has been boiled and then cooled?
Problem 45
- Why do fish die when placed in a tank filled with water that has been boiled and then cooled?
Problem 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?
Problem 47
Problem 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?
- Calculate the mass of nitrogen dissolved at room temperature in an 80.0-L home aquarium, assuming a total pressure of 1.0 atm and a mole fraction for nitrogen of 0.78.
Problem 49
Problem 51a
An aqueous NaCl solution is made using 112 g of NaCl diluted to a total solution volume of 1.00 L. Calculate the molarity of the solution. (Assume a density of 1.08 g/mL for the solution.)
Problem 51b
An aqueous NaCl solution is made using 112 g of NaCl diluted to a total solution volume of 1.00 L. Calculate the molality of the solution. (Assume a density of 1.08 g/mL for the solution.)
Problem 51c
An aqueous NaCl solution is made using 112 g of NaCl diluted to a total solution volume of 1.00 L. Calculate the mass percent of the solution. (Assume a density of 1.08 g/mL for the solution.)
Problem 52a
An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the molarity of the solution. (Assume a density of 1.05 g/mL for the solution.)
Problem 52b
An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the molality of the solution. (Assume a density of 1.05 g/mL for the solution.)
Problem 52c
An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the mass percent of the solution. (Assume a density of 1.05 g/mL for the solution.)
Problem 53
To what volume should you dilute 50.0 mL of a 5.00 M KI solution so that 25.0 mL of the diluted solution contains 3.05 g of KI?
- To what volume should you dilute 125 mL of an 8.00 M CuCl2 solution so that 50.0 mL of the diluted solution contains 4.67 g of CuCl2?
Problem 54
Problem 55
Silver nitrate solutions are often used to plate silver onto other metals. What is the maximum amount of silver (in grams) that can be plated out of 4.8 L of an AgNO3 solution containing 3.4% Ag by mass? Assume that the density of the solution is 1.01 g/mL.
Problem 56
A dioxin-contaminated water source contains 0.085% dioxin by mass. How much dioxin is present in 2.5 L of this water? Assume a density of 1.00 g/mL.
- A hard water sample contains 0.0085% Ca by mass (in the form of Ca2+ ions). How much water (in grams) contains 1.2 g of Ca? (1.2 g of Ca is the recommended daily allowance of calcium for adults between 19 and 24 years old.)
Problem 57
Problem 58
Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0011% Pb by mass. How much of the water (in mL) contains 150 mg of Pb? (Assume a density of 1.0 g/mL.)
- You can purchase nitric acid in a concentrated form that is 70.3% HNO3 by mass and has a density of 1.41 g>mL. Describe exactly how you would prepare 1.15 L of 0.100 M HNO3 from the concentrated solution.
Problem 59
Problem 61
Describe how to prepare each solution from the dry solute and the solvent. a. 1.00×102 mL of 0.500 M KCl b. 1.00×102 g of 0.500 m KCl c. 1.00×102 g of 5.0% KCl solution by mass
Problem 62b
Describe how to prepare each solution from the dry solute and the solvent. b. 125 g of 0.100 m NaNO3
Problem 62c
Describe how to prepare each solution from the dry solute and the solvent. c. 125 g of 1.0% NaNO3 solution by mass
- For a solution prepared by dissolving 28.4 g of glucose (C6H12O6) in 355 g of water with a final volume of 378 mL, calculate the concentration in each unit: a. molarity, b. molality, c. percent by mass, d. mole fraction, e. mole percent.
Problem 63
Problem 64a
A solution is prepared by dissolving 20.2 mL of methanol (CH3OH) in 100.0 mL of water at 25 °C. The final volume of the solution is 118 mL. The densities of methanol and water at this temperature are 0.782 g/mL and 1.00 g/mL, respectively. For this solution, calculate the concentration in each unit. a. molarity
Problem 64b
A solution is prepared by dissolving 20.2 mL of methanol (CH3OH) in 100.0 mL of water at 25 °C. The final volume of the solution is 118 mL. The densities of methanol and water at this temperature are 0.782 g/mL and 1.00 g/mL, respectively. For this solution, calculate the concentration in each unit. b. molality