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Problem 1
Ethanol 1CH CH OH 2 dissolves in hexane 1C H 2. Give the strongest type of intermolecular force between two sol- ute molecules, between two solvent molecules, and between a solute and solvent molecule. (LO 13.1) (a)
Problem 2
When lithium chloride dissolves in water, the temperature of the solution increases. Which diagram represents the enthalpy changes of the steps in the solution-making process? (LO 13.2)Problem 3
In which solvent does sodium acetate 1CH COONa2 have the highest solubility (a) Acetone CH3OCH3 (b) Methanol (CH3OH) (c) Ethanol (CH3CH2OH) (d) Pentane (CH3CH2CH2CH2CH3)Problem 4
Rubbing alcohol is a 90% (by mass) solution of isopropyl alcohol, C3H8O, in water. How many moles of isopropyl alcohol are in 50.0 g of rubbing alcohol? (LO 13.4) (a) 45 mol
Problem 5
Fluoride ion is added to drinking water at low concentra- tions to prevent tooth decay. What mass of sodium fluoride (NaF) should be added to 750 L of water to make a solution that is 1.5 ppm in fluoride ion? (LO 13.5) (a) 1.1 g (b) 2.5 g (c) 0.51 g (d) 3.1 gProblem 7
A 10.0 M aqueous solution of NaOH has a density of 1.33 g/cm3 at 25 C. Calculate the mass percent of the NaOH in the solution (a) 53.2% (b) 30.1% (c) 40.0% (d) 13.3%Problem 8
The molarity of a solution of sodium acetate (CH3COONa) at 20 C is 7.5 M. Use the graph showing the solubility of sodium acetate as a function of temperature to describe the solution. The solution is . (LO 13.7, 13.8)
(a) Saturated (b) Unsaturated (c) Supersaturated (d) Colloidal
Problem 9
A scuba diver is breathing compressed air that is 21% (by volume) oxygen at a depth of 66 ft. beneath the surface. The total pressure at this depth is 3.0 atm. The Henry's law constant (k) for O2 in water at a normal body temperature (37 °C ) is 1.93 * 10-3 mol>(L atm). What is the solubility of O2 in the blood of the diver at 66 ft. beneath the surface? (LO 13.9) (a) 1.22 * 10-3 M (b) 2.76 * 10-2 M (c) 1.22 * 10-1 M (d) 2.76 * 10-1 MProblem 10
Which of the following solutions has the lowest vapor pres- sure? (Assume complete dissociation for ionic compounds.) (LO 13.10) (a) An aqueous solution of 0.25 m Ca1NO322 (b) An aqueous solution of 0.30 m sodium chloride (NaCl) (c) A mixture of 50 mL of water and 50 mL of ethanol 1CH3CH2OH2 (d) A mixture of 25 mL of water and 50 mL of ethanol 1CH3CH2OH2Problem 12
12. A solution contains 4.08 g of chloroform 1CHCl32 and 9.29 g of acetone 1CH3COCH32. The vapor pressures at 35 °C of pure chloroform and pure acetone are 295 torr and 332 torr, respectively. Assuming ideal behavior, calculate the vapor pressure above the solution. (LO 13.12) (a) 256 torr (b) 314 torr (c) 325 torr (d) 462 torrProblem 13
How many kilograms of ethylene glycol (automobile anti- freeze, C2H6O2) dissolved in 3.55 kg of water are needed to lower the freezing point of water in an automobile radiator to - 22.0 °C? The molal freezing point depression constant for water is Kf = 1.86 1°C kg2>mol. (LO 13.13) (a) 0.865 kg (b) 0.0420 kg (c) 9.01 kg (d) 2.61 kgProblem 15
Hemoglobin is a large molecule that carries oxygen in the body. An aqueous solution that contains 2.61 g of hemoglo- bin in 100.0 mL has an osmotic pressure of 7.52 mmHg at 25 °C. What is the molar mass of the hemoglobin? Assume hemoglobin does not dissociate in water. (LO 13.15) (a) 1.96 * 103 g>mol (b) 84.8 g/mol (c) 6.45 * 104 g>mol (d) 3.65 * 103 g>molProblem 29
The following phase diagram shows part of the vapor- pressure curves for a pure liquid (green curve) and a solution of the first liquid with a second volatile liquid (red curve).
(a) Is the boiling point of the second liquid higher or lower than that of the first liquid?
Problem 30
The following phase diagram shows part of the liquid–vapor phase-transition boundaries for pure ether and a solution of a nonvolatile solute in ether.
(b) What is the approximate mo#lal concentration of the sol-ute? [Kb for ether is 2.021°C kg2>mol.]
Problem 33
Two beakers, one with pure water (blue) and the other with a solution of NaCl in water (green), are placed in a closed container as represented by drawing (a). Which of the draw- ings (b)–(d) represents what the beakers will look like after a substantial amount of time has passed?
Problem 36
If a single 5-g block of NaCl is placed in water, it dissolves slowly, but if 5 g of powdered NaCl is placed in water, it dis- solves rapidly. Explain.Problem 39
Which would you expect to have the larger hydration energy, SO42- or ClO4-? Explain.Problem 40
Classify the strongest type of intermolecular force in the follow- ing interactions: solvent–solvent, solvent–solute, and solute– solute when solid iodine 1I22 is placed in the water. Based on these interactions, predict whether I2 is soluble in water.Problem 45
The following pictures represent solutions of AgCl, which also may contain ions other than Ag+ and Cl- that are not shown. If solution 1 is a saturated solution of AgCl, classify solutions 2–4 as unsaturated, saturated, or supersaturated. (1) (2) (3) (4)Problem 47
Predict whether the solubility of butane, C4H10, is greater in water or benzene, C6H6.Problem 48
Arrange the following compounds in order of their expected increasing solubility in water: Br2, KBr, toluene (C7H8, a constituent of gasoline).Problem 54
The dissolution of CaCl2(s) in water is exothermic, with ΔHsoln= - 81.3 kJ>mol. If you were to prepare a 1.00 m solution of CaCl2 beginning with water at 25.0 °C, what would the final temperature of the solution be in °C? Assume that the specific heats of both pure H2O and the solution are the same, 4.18 J>1K g2.
Problem 56
Assuming that seawater is an aqueous solution of NaCl, what is its molarity? The density of seawater is 1.025 g/mL at 20 °C, and the NaCl concentration is 3.50 mass %.
Problem 58b
Propranolol 1C16H21NO22, a so-called beta-blocker that is used for treatment of high blood pressure, is effective at a blood plasma concentration of 50 ng/L. Express this concen- tration of propranolol in the following units: (b) Molarity
Problem 59b
Residues of the herbicide atrazine 1C8H14ClN52 in water can be detected at concentrations as low as 0.050 mg>L. Express this concentration of atrazine in the following units: (b) Molarity
Problem 60
How would you prepare each of the following solutions? (c) A solution of methyl alcohol (methanol) and water in which Xmethanol = 0.15 and Xwater = 0.85Problem 61
How would you prepare each of the following solutions? (a) 100 mL of a 155 ppm solution of urea, CH4N2O, in waterProblem 61b
How would you prepare each of the following solutions? (b) 100 mL of an aqueous solution whose K+ concentration is 0.075 M
Problem 62
How would you prepare 165 mL of a 0.0268 M solution of benzoic acid 1C7H6O22 in chloroform 1CHCl32?
Problem 64a
Which of the following solutions is more concentrated? (a) 0.500 M KCl or 0.500 mass % KCl in water
