Ch.13 - Solutions & Their Properties
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Problem 62
How would you prepare 165 mL of a 0.0268 M solution of benzoic acid 1C7H6O22 in chloroform 1CHCl32?
- Which of the following solutions is more concentrated? 1.75 M glucose or 1.75 m glucose in water?
Problem 64
Problem 64a
Which of the following solutions is more concentrated? (a) 0.500 M KCl or 0.500 mass % KCl in water
- Which of the following solutions has the higher molarity? (a) 10 ppm KI in water or 10,000 ppb KBr in water
Problem 65
- The ozone layer in the Earth's stratosphere has an average total pressure of 10 mm Hg 11.3 * 10-2 atm2. The partial pressure of ozone in the layer is about 1.2 * 10-6 mm Hg 11.6 * 10-9 atm2. What is the concentration of ozone in parts per million, assuming that the average molar mass of air is 29 g/mol?
Problem 68
- A person is medically considered to have lead poisoning if he or she has a concentration of greater than 10 mg of lead per deciliter of blood. What is this concentration in parts per billion? Assume that the density of blood is the same as that of water.
Problem 69
- What is the concentration of each of the following solutions? (b) The mole fraction of each component of a solution pre- pared by dissolving 2.25 g of nicotine, C10H14N2, in 80.0 g of CH2Cl2
Problem 70
- Household bleach is a 5.0 mass % aqueous solution of sodium hypochlorite, NaOCl. What is the molality of the bleach? What is the mole fraction of NaOCl in the bleach?
Problem 71
Problem 72
The density of a 16.0 mass % solution of sulfuric acid in water is 1.1094 g/mL at 25.0 °C. What is the molarity of the solution?
- What is the molality of the 40.0 mass % ethylene glycol 1C2H6O22 solution used for automobile antifreeze?
Problem 74
- Ethylene glycol, C2H6O2, is a colorless liquid used as auto-mobile antifreeze. If the density at 20 °C of a 4.028 m solu- tion of ethylene glycol in water is 1.0241 g/mL, what is the molarity of the solution? The molar mass of ethylene glycol is 62.07 g/mol
Problem 75
- Nalorphine 1C19H21NO3 2, a relative of morphine, is used to combat withdrawal symptoms in narcotics users. How many grams of a 1.3 * 10-3 m aqueous solution of nalor-phine are needed to obtain a dose of 1.5 mg?
Problem 76
Problem 78a
A 0.944 M solution of glucose, C6H12O6, in water has a density of 1.0624 g/mL at 20 °C. What is the concentration of this solution in the following units? (a) Mole fraction
Problem 78b
A 0.944 M solution of glucose, C6H12O6, in water has a density of 1.0624 g/mL at 20 °C. What is the concentration of this solution in the following units? (b) Mass percent
Problem 78c
A 0.944 M solution of glucose, C6H12O6, in water has a density of 1.0624 g/mL at 20 °C. What is the concentration of this solution in the following units? (c) Molality
- Lactose, C12H22O11, is a naturally occurring sugar found in mammalian milk. A 0.335 M solution of lactose in water has a density of 1.0432 g/L at 20 °C. What is the concentra- tion of this solution in the following units? (b) Mass percent
Problem 79
- Vinyl chloride (H2C=CHCl), the starting material from which PVC polymer is made, has a Henry’s law constant of 0.091 mol/L-atm at 25 °C. What is the solubility of vinyl chloride in water in mol/L at 25 °C and a partial pressure of 0.75 atm?
Problem 82
- Hydrogen sulfide, H₂S, is a toxic gas responsible for the odor of rotten eggs. The solubility of H₂S in water at STP is 0.195 M. What is the Henry’s law constant of H₂S at 0 °C? What is the solubility of H₂S in water at 0 °C and a partial pressure of 25.5 mm Hg?
Problem 83
- Fish generally need an O2 concentration in water of at least 4 mg/L for survival. What partial pressure of oxygen above the water in atmospheres at 0 °C is needed to obtain this concentration? The solubility of O2 in water at 0 °C and 1 atm partial pressure is 2.21 * 10-3 mol>L.
Problem 84
- At an altitude of 10,000 ft, the partial pressure of oxygen in the lungs is about 68 mm Hg. What is the concentration in mg/L of dissolved O2 in blood (or water) at this partial pres- sure and a normal body temperature of 37 °C? The solubil- ity of O2 in water at 37 °C and 1 atm partial pressure is 1.93 * 10-3 mol>L.
Problem 85
- Sulfur hexafluoride, which is used as a nonflammable insulator in high-voltage transformers, has a Henry’s law constant of 2.4 * 10⁻⁴ mol/L·atm at 25 °C. What is the solubility in mol/L of sulfur hexafluoride in water at 25 °C and a partial pressure of 2.00 atm?
Problem 86
- When 1 mL of toluene is added to 100 mL of benzene (bp 80.1 °C), the boiling point of the benzene solution rises, but when 1 mL of benzene is added to 100 mL of toluene (bp 110.6 °C), the boiling point of the toluene solution falls. Explain.
Problem 88
- When solid CaCl2 is added to liquid water, the temperature rises. When solid CaCl2 is added to ice at 0 °C, the temperature falls. Explain.
Problem 89
- Which of the following aqueous solutions has the (a) higher freezing point, (b) higher boiling point, (c) lower vapor pressure: 0.50 m sucrose (C12H22O11) or 0.35 m HNO3?
Problem 91
- What is the vapor pressure in mm Hg of a solution prepared by dissolving 5.00 g of benzoic acid (C7H6O2) in 100.00 g of ethyl alcohol (C2H6O) at 35 °C? The vapor pressure of pure ethyl alcohol at 35 °C is 100.5 mm Hg.
Problem 92
- What is the freezing point in °C of a solution prepared by dissolving 7.40 g of MgCl2 in 110 g of water if the value of Kf for water is given in Table 13.4, and the van’t Hoff factor for MgCl2 is i = 2.7?
Problem 94
- Assuming complete dissociation, what is the molality of an aqueous solution of KBr whose freezing point is -2.95 °C? The molal freezing-point-depression constant of water is given in Table 13.4.
Problem 95
- When 9.12 g of HCl was dissolved in 190 g of water, the freezing point of the solution was - 4.65 °C. What is the value of the van't Hoff factor for HCl?
Problem 96
- A solution concentration must be expressed in molality when considering boiling-point elevation or freezing-point depression but can be expressed in molarity when consider- ing osmotic pressure. Why?
Problem 101
- What is the vapor pressure in mm Hg of the following solu-tions, each of which contains a nonvolatile solute? The vapor pressure of water at 45.0 °C is 71.93 mm Hg. (b) A solution of 10.0 g of LiCl in 150.0 g of water at 45.0 °C, assuming complete dissociation
Problem 102