Chem 1411 Ch. 10 Multiple Choice

Pure acetic acid, often called glacial acetic acid, is a liquid with a density of 1.049 g/mL. Which calculation correctly shows how to determine the volume of glacial acetic acid necessary to prepare 250 mL of 0.400 M CH3CO2H(aq)? a. b. c. d. e.

a.

The molal freezing point constant for water is -1.86°C/m. At what temperature will a solution containing 8.27 g CaCl2 and 45.0 g H2O begin to freeze? Assume that no ion-pairing occurs between Ca2+ and Cl-. a. -9.24°C b. -4.62°C c. -0.804°C d. -0.749°C e. +4.62°C

a. -9.24°C

If 25.00 mL of 2.00 M NaCl is transferred by pipet into a volumetric flask and diluted to 5.00 L, what is the molarity of the diluted NaCl? a. 0.0100 M b. 0.0160 M c. 0.0625 M d. 0.400 M e. 16.0 M

a. 0.0100 M

A gas mixture has mole fractions of 0.24 oxygen and 0.76 nitrogen. If the total pressure of the gases is 1.44 atm at 325 K, what is the concentration, in molarity, of oxygen? (R = 0.0821 L∙atm/mol∙K) a. 0.013 M b. 0.017M c. 0.041 M d. 0.54 M e. 0.069 M

a. 0.013 M

In 1.00 atm of pure oxygen, the solubility of O2(g) in water is 1.26 x 10⁻³ M at 25.0°C. The mole fraction of oxygen in air is 0.210. If the atmospheric pressure is 0.979 atm, what is the solubility of oxygen in air at 25.0°C? a. 2.59 x 10⁻⁴ M b. 2.65 x 10⁻³ M c. 5.87 x 10⁻³ M d. 6.00 x 10⁻³ M e. 3.86 x 10³ M

a. 2.59 x 10⁻⁴ M

What mass of Cu(NO3)2 (187.6 g/mol) is present in 25.0 g of 1.00 m Cu(NO3)2(aq)? a. 3.95 g b. 4.69 g c. 13.8 g d. 25.0 g e. 63.5 g

a. 3.95 g

If sea water contains 15 ppm gold, how many kilograms of sea water must be processed to remove 1.00 g of gold? a. 67 kg b. 97 kg c. 150 kg d. 6.7 x 10³ kg e. 15 x 10⁴ kg

a. 67 kg

Which of the following electrolytes is likely to have a van't Hoff factor equal to 3? a. CaI2 b. Na3PO4 c. KCl d. answers a and b e. answers a, b, and c

a. CaI2

To prepare a solution that is 15.0% aqueous KCl by mass, one should a. dissolve 15.0 g KCl in 85.0 g H2O. b. dissolve 15.0 g KCl in 1.00 x 10² g H2O. c. dissolve 15.0 g KCl in 0.850 mol H2O. d. dissolve 0.150 mol KCl in 0.850 mol H2O. e. dissolve 0.150 mol KCl in 1.00 mol H2O.

a. dissolve 15.0 g KCl in 85.0 g H2O.

All of the following are colligative properties EXCEPT a. gas solubility as a function of partial pressure above a solution (Henry's law). b. osmotic pressure. c. vapor pressure lowering. d. boiling point elevation. e. freezing point depression.

a. gas solubility as a function of partial pressure above a solution (Henry's law).

If 77.5 g of ethylene glycol (HOCH2CH2OH) is added to 422.5 g of water, what is the mole fraction of ethylene glycol? a. 0.00296 b. 0.0506 c. 0.183 d. 0.949 e. 2.96

b. 0.0506

What concentration of silver nitrate (in ppm) is present in 7.1 x 10⁻⁷ M AgNO3(aq)? For very dilute aqueous solutions, you can assume the solution's density is 1.0 g/mL. The molar mass of AgNO3 is 169.9 g/mol. a. 0.0071 ppm b. 0.12 ppm c. 0.71 ppm d. 1.7 ppm e. 8.3 ppm

b. 0.12 ppm

Concentrated phosphoric acid is 85.0% by mass H3PO4. If the molarity of concentrated H3PO4 is 14.5 M, what is the density? a. 0.60 g/mL b. 1.67 g/mL c. 1.87 g/mL d. 1.95 g/mL e. 2.07 g/mL

b. 1.67 g/mL

A 0.230 m solution of an unknown electrolyte depresses the freezing point of water by 0.821°C. What is the Van't Hoff factor for this electrolyte? The freezing point depression constant for water is 1.86°C/m. a. 0.521 b. 1.92 c. 2.00 d. 2.30 e. 4.41

b. 1.92

A bottle of phosphoric acid is labeled "85.0% H3PO4 by mass; density = 1.689 g/cm3." Calculate the molarity of phosphoric acid in the solution. a. 16.7 M b. 14.6 M c. 12.2 M d. 8.67 M e. 0.146 M

b. 14.6 M

What volume of 6.0 M HNO3 is required to prepare 250 mL of 0.40 M HNO3? a. 9.7 mL b. 17 mL c. 27 mL d. 38 mL e. 270 L

b. 17 mL

At 25°C, what is the osmotic pressure of a homogeneous solution consisting of 18.0 g urea (CON2H4) diluted with water to 3.00 L? (R = 0.0821 L∙atm/mol∙K) a. 0.205 atm b. 2.44 atm c. 7.33 atm d. 12.3 atm e. 14.7 atm

b. 2.44 atm

Pure acetic acid, CH3CO2H(l), has a density of 1.049 g/mL. To prepare 1.00 L of 6.00 M CH3CO2H(aq), one may a. dilute 175 g of acetic acid to a volume of 1.00 L. b. dilute 343 mL of acetic acid to a volume of 1.00 L. c. dilute 360 mL of acetic acid to a volume of 1.00 L. d. dilute 382 mL of acetic acid to a volume of 1.00 L. e. dilute 1049 g of acetic acid to a volume of 1.00 L.

b. dilute 343 mL of acetic acid to a volume of 1.00 L.

A substance that dissolves in water and conducts electricity when present in an aqueous solution is a. metallic. b. ionic. c. molecular. d. network covalent. e. none of the above.

b. ionic

Arrange the molecules below in order of increasing solubility in water. a. methane < methanol < chloromethane b. methane < chloromethane < methanol c. chloromethane < methanol < methane d. chloromethane < methane < methanol e. methanol < methane < chloromethane

b. methane < chloromethane < methanol

What concentration unit is necessary for the calculation of boiling point elevation? a. molarity b. molality c. mass fraction d. mole fraction e. parts per million

b. molality

If 26.5 g of methanol (CH3OH) is added to 735 g of water, what is the molality of the methanol? a. 0.0348 m b. 2.03 m c. 1.13 m d. 3.61 m e. 36.1 m

c. 1.13 m

At 1.00 atm, 1.64 x 10⁻³ g H2(g) will dissolve in 1.0 L of water. What pressure of gas is necessary to obtain a concentration of 1.0 x 10⁻³ M H2(g)? a. 6.1 x 10⁻⁴ atm b. 4.4 x 10⁻² atm c. 1.2 atm d. 2.2 x 10³ atm e. 1.6 x 10³ atm

c. 1.2 atm

Silver chloride is a relatively insoluble salt. Only 1.92 mg of AgCl will dissolve per liter of water at 25°C. What concentration of Ag+, in molarity units, can be present in water at 25°C? a. 3.35 x 10⁻⁶ M b. 6.70 x 10⁻⁶ M c. 1.34 x 10⁻⁵ M d. 9.60 x 10⁻⁴ M e. 1.92 x 10⁻³ M

c. 1.34 x 10⁻⁵ M

Silver chloride is a relatively insoluble salt. Only 1.92 mg of AgCl will dissolve per liter of water at 25°C. How many parts per million of Ag+ can be present in water at 25°C? Assume the density of the solution equals the density of water, 1.00 g/mL. a. 0.52 ppm b. 0.93 ppm c. 1.45 ppm d. 9.30 ppm e. 52.0 ppm

c. 1.45 ppm

What mass of ethylene glycol, when mixed with 225 g H2O, will reduce the equilibrium vapor pressure of H2O from 1.00 atm to 0.800 atm at 100°C? The molar masses of water and ethylene glycol are 18.02 g/mol and 62.07 g/mol, respectively. Assume ideal behavior for the solution. a. 15.6 g b. 49.9 g c. 194 g d. 969 g e. 3.10 x 10³ g

c. 194 g

An aqueous solution contains 11.5 g of NaCl in 250.2 g of water. Calculate the vapor pressure of this solution at 25.0°C. The vapor pressure of pure water is 23.8 mm Hg at 25.0°C. a. 3.38 mm Hg b. 21.8 mm Hg c. 23.5 mm Hg d. 24.1 mm Hg e. 31.3 mm Hg

c. 23.5 mm Hg

Concentrated sodium hydroxide is 19.4 M and has a density of 1.54 g/mL. What is the molality of concentrated NaOH? a. 12.6 m b. 19.8 m c. 25.4 m d. 29.9 m e. 50.4 m

c. 25.4 m

The mole fraction of calcium chloride in an aqueous solution is 0.0724. What is the percent mass of CaCl2 in the solution? a. 4.46% b. 7.24% c. 32.5% d. 36.2% e. 50.0%

c. 32.5%

A solution is prepared by dissolving 5.00 g of an unknown molecular solid in water to make 1.00 L of solution. The osmotic pressure of the solution is 1.61 atm at 25°C. What is the molar mass of the solute? (R = 0.0821 L∙atm/mol∙K) a. 6.37 g/mol b. 58.44 g/mol c. 76.0 g/mol d. 102 g/mol e. 180.2 g/mol

c. 76.0 g/mol

What is the boiling point of a solution containing 0.80 g caffeine, C8H10N4O2, dissolved in 13.20 g benzene? The boiling point of pure benzene is 80.1°C and the molal boiling point constant, Kb, is 2.53°C/m. a. 79.8°C b. 80.4°C c. 80.9°C d. 85.2°C e. 88.2°C

c. 80.9°C

What is the molar mass of a nonpolar molecular compound if 3.42 grams dissolved in 41.8 grams benzene begins to freeze at 1.17°C? The freezing point of pure benzene is 5.50°C and the molal freezing point constant, Kf, is -5.12°C/m. a. 2.89 g/mol b. 69.2 g/mol c. 96.7 g/mol d. 126 g/mol e. 358 g/mol

c. 96.7 g/mol

Which of the following liquids will be miscible with water in any proportions: ethanol (CH3CH2OH), carbon tetrachloride (CCl4), hexane (C6H14), and/or formic acid (HCO2H)? a. ethanol and carbon tetrachloride b. carbon tetrachloride and hexane c. ethanol and formic acid d. ethanol, carbon tetrachloride, and benzene e. carbon tetrachloride, and formic acid

c. ethanol and formic acid

Equal masses of water and ethylene glycol (C2H6O2) are mixed. At what temperature will the mixture freeze? The molal freezing point constant for water is -1.86°C/m. a. -115°C b. -93.0°C c. -42.0°C d. -30.0°C e. -0.93°C

d. -30.0°C

Which of the following aqueous solutions will freeze at the lowest temperature? a. 0.10 m KCl b. 0.20 m C6H12O6 (glucose) c. 0.050 m AlCl3 d. 0.15 m SrBr2 e. All of the above freeze at the same temperature.

d. 0.15 m SrBr2

Which of the following statements concerning the solubility of a gas in a liquid are true? 1. Solubility decreases with increasing temperature. 2. Solubility increases as the pressure of the gas over the liquid increases. 3. Solubility is dependent on the surface area of the the liquid. a. 1 only b. 2 only c. 3 only d. 1 and 2 e. 1 and 3

d. 1 and 2

Which of the following statements concerning osmosis is/are CORRECT? 1. Osmosis involves the movement of a solvent through a semipermeable membrane. 2. Solvents move from regions of high solute concentration to regions of lower solute concentration. 3. Osmotic pressure is a colligative property. a. 1 only b. 2 only c. 3 only d. 1 and 3 e. 1, 2, and 3

d. 1 and 3

The Henry's law constant for O2 in water at 25°C is 1.26 x 10⁻³ M/atm. What partial pressure of O2 is necessary to achieve an equilibrium concentration of 1.5 x 10⁻³ M O2? a. 1.9 x 10⁻⁶ atm b. 0.24 atm c. 0.84 atm d. 1.2 atm e. 5.3 x 10⁵ atm

d. 1.2 atm

The Henry's law constant for the solubility of nitrogen in water is 6.4 x 10⁻⁴ M/atm at 25°C. At 0.75 atm of N2, what mass of N2(g) dissolves in 1.0 L of water at 25°C? a. 4.8 x 10⁻⁴ g b. 8.5 x 10⁻⁴ g c. 4.5 x 10⁻³ g d. 1.3 x 10⁻² g e. 2.4 x 10⁻² g

d. 1.3 x 10⁻² g

A solution is prepared by dissolving 4.21 g of a nonelectrolyte in 50.0 g of water. If the boiling point increases by 0.203°C, what is the molar mass of the solute? The boiling point elevation constant for water is 0.512°C/m. a. 33.4 g/mol b. 111 g/mol c. 172 g/mol d. 212 g/mol e. 810 g/mol

d. 212 g/mol

What is the equilibrium partial pressure of water vapor above a mixture of 44.0 g H2O and 56.0 g HOCH2CH2OH at 35°C. The partial pressure of pure water at 35.0°C is 42.2 mm Hg. Assume ideal behavior for the solution. a. 0.730 Hg b. 18.7 mm Hg c. 23.6 mm Hg d. 30.8 mm Hg e. 58.8 mm Hg

d. 30.8 mm Hg

What mass of HCl is required to prepare 1.00 kg of 5.5% by mass aqueous HCl? a. 0.018 g b. 5.5 g c. 18 g d. 55 g e. 550 g

d. 55 g

Concentrated sulfuric acid is 18.0 M and has a density of 1.84 g/mL. Calculate the percent mass of sulfuric acid in concentrated H2SO4. a. 17.7% b. 32.5% c. 78.2% d. 96.0% e. 99.4%

d. 96.0%

To prepare 0.250 L of 0.100 M aqueous NaCl (58.4 g/mol), one may a. dissolve 0.100 g of NaCl in 250 mL of water. b. dissolve 1.46 g of NaCl in 250 mL of water. c. dissolve 0.100 g of NaCl in enough water to make 0.250 kg of solution. d. dissolve 1.46 g of NaCl in enough water to make 0.250 L of solution. e. dissolve 0.100 g NaCl in 0.250 kg of water.

d. dissolve 1.46 g of NaCl in enough water to make 0.250 L of solution.

All of the following statements are correct EXCEPT a. the solubility of a gas in water decreases as the water temperature increases. b. dissolving a solid in water is usually an exothermic process. c. when an equilibrium is established between molecules in a solid and a solution, the solution is said to be saturated. d. if a precipitate forms when a solution is cooled, the solution is supersaturated. e. network covalent solids are usually insoluble in water.

d. if a precipitate forms when a solution is cooled, the solution is supersaturated.

What concentration unit is necessary for the calculation of vapor pressure lowering? a. molarity b. molality c. mass fraction d. mole fraction e. density

d. mole fraction

Concentrated nitric acid is 70.4% HNO3 by mass. What is the mole fraction of nitric acid? a. 0.0112 b. 0.0620 c. 0.171 d. 0.377 e. 0.405

e. 0.405

What is the mole fraction of water in a solution that is 33.3% by mass ethylene glycol? The molar mass of ethylene glycol, HOCH2CH2OH, is 62.07 g/mol. a. 0.127 b. 0.290 c. 0.368 d. 0.667 e. 0.873

e. 0.873

The molal boiling point constant for water is 0.52°C/m. At what temperature will a mixture of 45.0 g of NaCl and 0.500 kg of water boil? a. 98.4°C b. 99.2°C c. 100.0°C d. 100.8°C e. 101.6°C

e. 101.6°C

Maple syrup is made from the sap of the maple tree. When the sap is tapped from the maple tree it is 2.0% by mass sucrose. Maple syrup is 66% by mass sucrose. What mass of sap would be required to make 0.5 kg of maple syrup? a. 0.50 kg b. 2.0 kg c. 66 kg d. 15 kg e. 17 kg

e. 17 kg

A solution is prepared by dissolving 4.78 g of an unknown nonelectrolyte in enough water to make 375 mL of solution. The osmotic pressure of the solution is 1.33 atm at 27°C. What is the molar mass of the solute? (R = 0.0821 L∙atm/mol∙K) a. 0.0203 g/mol b. 21.2 g/mol c. 49.4 g/mol d. 96.8 g/mol e. 236 g/mol

e. 236 g/mol

A 15 meter by 12 meter pool of water has a depth of 2.2 meters. What mass of silver ion is present in the reservoir if the concentration of silver ion is 0.14 ppm? (1 m3 = 1000 L; assume the density of the solution is 1.00 g/mL) a. 5.5 x 10⁻⁴ g b. 5.5 x 10⁻² g c. 0.55 g d. 5.5 g e. 55 g

e. 55 g

An aqueous solution is composed of 7.50 g NaCl (MM = 58.44 g/mol) diluted to 0.100 L. Calculate the osmotic pressure of the solution at 298 K. (R = 0.0821 L∙atm/mol∙K) a. 5.83 atm b. 9.22 atm c. 18.3 atm d. 31.4 atm e. 62.8 atm

e. 62.8 atm

Henry's law states that gas solubility is a. directly proportional to temperature of the solution. b. directly proportional to the molar mass of the gas. c. inversely proportional to the combined pressure of all gases over the solution. d. inversely proportional to the pressure of the gas over the solution. e. directly proportional to the pressure of the gas over the solution.

e. directly proportional to the pressure of the gas over the solution.

Arrange the molecules below in order of increasing solubility in water. a. dimethyl ether < methane < methanol b. dimethyl ether < methanol < methane c. methane < methanol< dimethyl ether d. methanol < dimethyl ether < methane e. methane < dimethyl ether < methanol

e. methane < dimethyl ether < methanol

What is the definition of molarity? a. mass of solute per liter of solvent b. mass of solute per kg of solvent c. moles of solute per kg of solvent d. moles of solute in one liter of solvent e. moles of solute per liter of solution

e. moles of solute per liter of solution