Introductory Chemistry, 5e (Tro)
Chapter 13 Solutions
13.1 True/False Questions
1) The tragedy at Lake Nyos in Cameroon, West Africa was due to the sudden release of
excessive amounts of nitrogen dissolved in the lake water.
2) The tragedy at Lake Nyos in Cameroon, West Africa, was due to the sudden release of
excessive amounts of carbon monoxide dissolved in the lake water.
3) A solution is a homogeneous mixture of two or more substances.
4) Air is an example of a gaseous solution.
5) Steel is an example of a solid solution.
6) The minor component in a solution is called the solvent.
7) The major component in a solution is called the solute.
8) The fact that the oceans contain salt water shows that polar solvents dissolve ionic solutes.
9) Ionic solutes typically dissolve in nonpolar solvents.
10) Vitamin C is a water-soluble vitamin, so it is likely that this vitamin is polar.
11) It would be expected that methanol (CH3OH) would be more soluble in water than methane
(CH4) would be.
12) When a chunk of gold is melted and poured into the shape of an ingot, an aqueous solution of
gold has been created.
13) Solubility is formally defined as the amount of a compound that can be dissolved in water.
14) A saturated solution holds the maximum amount of solute under the solution conditions.
15) A supersaturated solution is unstable and crystallization usually occurs.
16) Salt water is an example of a strong electrolyte solution.
17) A sugar solution is an example of a weak electrolyte solution.
18) The solubility of solids in water generally increases with increasing temperature.
19) Sugar solutions conduct electricity because the dissolved particles are molecules.
20) Tap water contains dissolved nitrogen and oxygen.
21) The solubility of gases in water decreases with increasing temperature.
22) Warm beer goes flat quicker than cold beer.
4
23) The solubility of gases in water increases with increasing pressure above the water.
24) A solution that is 35 percent by mass NaCl contains of NaCl dissolved in
of water.
25) A solution that is 13.58 percent by mass of sugar contains of sugar dissolved in
of water.
26) Molarity is defined as the moles of solute per liter of solution.
27) The molarity of a solution prepared by dissolving of NaCl in 1000 mL water is
.
28) One liter of 6.0 M HNO3 contains the same number of H+ ions as does one liter of 6.0 M
H2SO4.
29) One liter of a 2.0 M NaOH (aq) solution contains the same number of Na+ ions as does one
liter of a 1.0 M Na2CO3 (aq) solution.
30) If 50 grams of salt dissolves into 250 grams of water, the resulting solution must have a mass
of 300 grams.
31) A stock solution is a more concentrated form than what is typically used in a lab. It often
requires further dilution.
32) Upon completing a dilution from a stock solution, you will always have more volume of
solution than you started with and it will have a lower concentration than the stock solution.
33) Molality is calculated by dividing grams of solute by kilograms of solution.
34) The terms “molarity” and “molality” are considered identical and can always be used
interchangeably.
35) Colligative properties are independent of the amount of solute in solution.
36) Adding a nonvolatile solute to a liquid will cause boiling point depression and freezing point
elevation.
37) A sample of salt water will freeze at a higher temperature than a sample of pure water.
38) A 0.10 molality solution of the sugar glucose (molecular weight = 180.10 g/mol) and a 0.10
molality solution of sucrose (molecular weight = 342.34 g/mol) would both boil at the same
temperature.
39) A semipermeable membrane allows only half the amount of a substance to pass through it.
40) Osmosis is the process in which a solvent moves from an area of low solute concentration to
an area of high solute concentration.
41) If you put a living cell into seawater containing a higher concentration of sodium chloride,
the cell loses water through osmosis.
42) Osmotic pressure is the pressure required to completely reverse the direction of solvent
movement in osmosis.
13.2 Multiple Choice Questions
1) The tragedy at Lake Nyos in Cameroon, West Africa, was caused by:
A) the release of excessive amounts of nitrogen gas that had been dissolved in the water at the
bottom of the lake.
B) the release of excessive amounts of oxygen gas that had been dissolved in the water at the
bottom of the lake.
C) the release of excessive amounts of carbon dioxide that had been dissolved in the water at the
bottom of the lake.
D) the release of excess water stored in the volcanic lake which flooded the village below.
E) none of the above
2) Which of the following substances is NOT a solution?
A) air
B) brass
C) vodka
D) copper
E) All of the above are solutions.
3) Which of the following substances is NOT a solution?
A) humid air
B) beer
C) oxygen
D) steel
E) All of the above are solutions.
4) Which of the following substances is NOT a solution?
A) homogenized milk
B) bronze
C) sea water
D) soda
E) All of the above are solutions.
5) Suppose a vodka martini contains 30% alcohol with the remaining portion of the drink
composed of water. What is the solute in this type of martini?
A) water
B) alcohol
C) ice
D) olive
E) none of the above
6) The oxygen in the air we breath is classified as:
A) the solute in a homogeneous gas mixture.
B) the solvent in a homogeneous gas mixture.
C) the solute in a heterogeneous gas-liquid mixture.
D) the solvent in a simple mixture.
E) none of the above
7) Hexane, a nonpolar solvent, will dissolve which of the following substances?
A) sodium chloride
B) oil
C) ammonium acetate
D) vinegar (acetic acid)
E) none of the above
8) Which of these compounds would you expect to be least soluble in water?
A) CH3OH
B) NaCl
C) N2
D) NH3
E) not enough information
9) Which compound below forms an electrolyte solution when dissolved in water?
A) Cl2
B) KOH
C) CH3CH2OH
D) C12H22O11 (sucrose)
E) none of the above
10) In order for a solute to dissolve in solution:
A) the solute-solvent forces must be greater than the solute-solute forces.
B) the solute-solute forces must be greater than the solute-solvent forces.
C) the solute-solvent forces must equal the solute-solute forces.
D) the polarity of the solute and solvent must be opposite.
E) none of the above
11) If the solubility of sodium acetate (Molar mass = 82 g/mol) is 76 grams per 100 grams of
water, which of the following solutions would be considered supersaturated?
A) 8.5 moles of sodium acetate dissolved in 1 L of water
B) 5.5 moles of sodium acetate dissolved in 500 mL of water
C) 1.8 moles of sodium acetate dissolved in 300 mL of water
D) 1.2 moles of sodium acetate dissolved in 200 mL of water
E) none of the above
12) If the solubility of sodium chloride is 36 grams per 100 grams of water, which of the
following solutions would be considered unsaturated?
A) 5.8 moles of NaCl dissolved in 1 L of water
B) 3.25 moles of NaCL dissolved in 500 ml of water
C) 1.85 moles of NaCl dissolved in 300 ml of water
D) none of the above
13) The solubility of Pb(NO3)2 is 55 grams per 100 g H2O at 20°C. Which term would properly
describe a solution where 44 grams of Pb(NO3)2 is added to 100 grams of water at this
temperature?
A) insoluble
B) unsaturated
C) saturated
D) supersaturated
E) none of the above
14) If you prepare a solution by adding sufficient amount of solute so that after heating and
cooling the solution there is a visible amount of solid solute left in the bottom of the beaker, the
solution would be considered ________.
A) unsaturated
B) saturated
C) supersaturated
D) thermally saturated
E) none of the above
15) Which of the following compounds is a strong electrolyte?
A) HCl
B) NaCl
C) N Cl
D) Na
E) all of the above
16) Which of the following compounds is a strong electrolyte?
A)
B)
C)
D) Na
E) all of the above
17) The solubility of solids in water:
A) is independent of the temperature.
B) increases with increasing temperature.
C) decreases with increasing temperature.
D) Solids are not soluble in water.
E) none of the above
18) The solubility of solids in water:
A) is independent of pressure above solution.
B) increases with increasing pressure above solution.
C) decreases with increasing pressure above solution.
D) Solids are not soluble in water.
E) none of the above
19) When an ionic compound dissolves in water:
A) the solvent-solute attractive forces overcome the solute-solute attractions.
B) the positive end of water dipoles attract the negative ions.
C) the negative end of water dipoles attract the positive ions.
D) each of the above (A, B, and C) occurs.
E) none of the above (A, B, or C) occurs.
20) Which among the following is NOT true about the solubility of a solid in water?
A) The solubility is not affected by pressure.
B) The solubility generally increases as temperature increases.
C) Solid crystallizes when a saturated solution is prepared at a higher temperature and then
cooled.
D) A saturated solution prepared at a lower temperature becomes unsaturated when heated to a
higher temperature.
E) none of the above
21) Solubility of gases in water:
A) is independent of pressure above solution.
B) increases with increasing pressure above solution.
C) decreases with increasing pressure above solution.
D) Gases are not soluble in water.
E) none of the above
22) The solubility of gases in water:
A) is independent of temperature.
B) increases with increasing temperature.
C) decreases with increasing temperature.
D) gases are not soluble in water.
E) none of the above
23) The solubility of a gas in a liquid can always be increased by:
A) increasing the temperature of the solvent.
B) decreasing the polarity of the solvent.
C) decreasing the pressure of the gas above the solvent.
D) increasing the pressure of the gas above the solvent.
E) none of the above
24) A solution is saturated in both nitrogen gas (N2) and sodium iodide (NaI) at 50°C. When the
solution is cooled to 25°C, which of the following is most likely to occur?
A) Some nitrogen gas bubbles out of solution.
B) Some sodium iodide will precipitate out of solution.
C) Both A and B will happen.
D) Nothing will happen.
E) not enough information
25) When preparing sodium hydroxide solution, it is best to use water that does not contain any
dissolved carbon dioxide as it reacts with the sodium hydroxide. Removing the carbon dioxide
can be accomplished by:
A) vigorously stirring the solution.
B) using water fresh out of the purification system.
C) boiling the water.
D) Nothing can be done to remove dissolved gases.
E) none of the above
26) We dissolve 2.45 g of sugar in 200.0 g water. What is the mass percent of sugar in the
solution?
A) 1.21%
B) 1.23%
C) 2.42%
D) 123%
E) none of the above
27) A solution contains 100.0 g water, 10.0 g NaCl, and 15.0 g methanol. What is the mass
percent of methanol in the solution?
A) 8.00%
B) 10.0%
C) 12.0%
D) 15.0%
E) none of the above
28) What is the mass percent of a solution prepared by dissolving of solid into
of water?
A) 47.8%
B) 58.4%
C) 32.4%
D) The identity of the compound must be known.
E) none of the above
29) What is the mass percent of an ammonium carbonate solution prepared by dissolving
of solid into of water?
A) 84.1%
B) 72.7%
C) 45.7%
D) 54.3%
E) none of the above
30) What is the mass percent of a sodium fluoride solution prepared by dissolving of
sodium fluoride into of water?
A) 26.9%
B) 42.3%
C) 70.3%
D) 29.7%
E) none of the above
31) How many grams of a 23.4% by mass NaF solution is needed if you want to have
of NaF?
A) 55.9
B) 31.1
C) 13.1
D) 239
E) none of the above
32) How many moles of NaF are in 34.2 grams of a 45.5% by mass NaF solution?
A) 0.814
B) 75.2
C) 15.6
D) 0.371
E) none of the above
33) What is the molarity of a solution prepared by dissolving NaI in ?
A) 42.8
B) 0.0714
C) 2.86
D) 0.286
E) none of the above
34) You need to prepare 2.00 L of 0.100 M Na2CO3 solution. The best procedure is to weigh
out:
A) 10.6 g Na2CO3 and add 2.00 L of water to it.
B) 21.2 g Na2CO3 and add 2.00 L of water to it.
C) 10.6 g Na2CO3 and add water until the final solution has a volume of 2.00 L.
D) 21.2 g Na2CO3 and add water until the final solution has a volume of 2.00 L.