46) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3.
Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2 into the bloodstream. What will be
the effect on pH of blood as that blood first comes in contact with respiring cells?
A) Blood pH will decrease slightly.
B) Blood pH will increase slightly.
C) Blood pH will remain unchanged.
D) Blood pH will first increase, then decrease as CO2 combines with hemoglobin.
E) Blood pH will first decrease, then increase sharply as CO2 combines with hemoglobin.
47) A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the
beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this
mixing?
A) The concentration of Na+ ion rises.
B) The concentration of Cl– ion will be 0.1 M.
C) The concentration of undissociated H2O molecules remains unchanged.
D) The pH of the beaker’s contents will be neutral.
E) The pH of the beaker’s contents falls.
48) Equal volumes (5 mL) of vinegar from a freshly opened bottle are added to each of the following
solutions. After complete mixing, which of the mixtures will have the highest pH?
A) 100 mL of pure water
B) 100 mL of freshly brewed coffee
C) 100 mL of household cleanser containing 0.5 M ammonia
D) 100 mL of freshly squeezed orange juice
E) 100 mL of tomato juice
49) Increased atmospheric CO2 concentrations might have what effect on seawater?
A) Seawater will become more acidic, and bicarbonate concentrations will decrease.
B) Seawater will become more alkaline, and carbonate concentrations will decrease.
C) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate.
D) Seawater will become more acidic, and carbonate concentrations will decrease.
E) Seawater will become more acidic, and carbonate concentrations will increase.
50) How would acidification of seawater affect marine organisms?
A) Acidification would increase dissolved carbonate concentrations and promote faster growth of corals
and shell-building animals.
B) Acidification would decrease dissolved carbonate concentrations and promote faster growth of corals
and shell-building animals.
C) Acidification would increase dissolved carbonate concentrations and hinder growth of corals and
shell-building animals.
D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and
shell-building animals.
E) Acidification would increase dissolved bicarbonate concentrations, and cause increased calcification
of corals and shellfish.
51) One idea to mitigate the effects of burning fossil fuels on atmospheric CO2 concentrations is to pipe
liquid CO2 into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO2 is
heavier than water. What potential effects might result from implementing such a scheme?
A) increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the
deep water
B) increased carbonate concentrations in the deep waters
C) reduced growth of corals from a change in the carbonate—bicarbonate equilibrium
D) no effect because carbon dioxide is not soluble in water
E) both increased acidity of the deep waters and changes in the growth of bottom-dwelling organisms
with calcium carbonate shells
52) If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that
A) the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
B) the concentration of H+ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm.
C) the concentration of H+ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix.
D) the mitochondrial matrix is more acidic than the cytoplasm.
E) the concentration of H+ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix.
Art Questions
53) Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is
most likely
A) positively charged.
B) negatively charged.
C) without charge.
D) hydrophobic.
E) nonpolar.
54) How many grams would be equal to 1 mol of the compound shown in the figure above?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342
55) How many grams of the compound in the figure above would be required to make 1 L of a 0.5 M
solution?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342
56) How many grams of the compound in the figure above would be required to make 2.5 L of a 1 M
solution?
(carbon = 12, oxygen = 16, hydrogen = 1)
A) 29
B) 30
C) 60
D) 150
E) 342
57) A small birthday candle is weighed, then lighted and placed beneath a metal can containing 100 mL
of water. Careful records are kept as the temperature of the water rises. Data from this experiment are
shown on the graph. What amount of heat energy is released in the burning of candle wax?
A) 0.5 kilocalories per gram of wax burned
B) 5 kilocalories per gram of wax burned
C) 10 kilocalories per gram of wax burned
D) 20 kilocalories per gram of wax burned
E) 50 kilocalories per gram of wax burned
17
58) Identical heat lamps are arranged to shine on identical containers of water and methanol (wood
alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds
of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. Which
of the following graphs correctly describes what will happen to the temperature of the water and the
methanol?
A)
B)
C)
D)
E)
59) Which of these molecules would be soluble in water?
A)
B)
C)
D)
E)
20
60) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3.
Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled
water, which of the following graphs correctly describes the results?
A)
B)
C)
D)
E)
Scenario Questions
61) You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol).
The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among
methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.
A) Equal amounts of NaCl crystals will dissolve in both water and methanol.
B) NaCl crystals will NOT dissolve in either water or methanol.
C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.
D) NaCl crystals will dissolve readily in methanol but will not dissolve in water.
E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more
crystals are added, the crystals will begin to dissolve faster and faster.
62) You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of
NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCl and 20 mL of
the NaOH. After complete stirring, the pH of the mixture will be
A) 2.0.
B) 12.0.
C) 7.0.
D) 5.0.
E) 9.0.
End-of-Chapter Questions
The following questions are from the end-of–chapter “Test Your Understanding” section in Chapter 3 of
the textbook.
63) Many mammals control their body temperature by sweating. Which property of water is most
directly responsible for the ability of sweat to lower body temperature?
A) water’s change in density when it condenses
B) water’s ability to dissolve molecules in the air
C) the release of heat by the formation of hydrogen bonds
D) the absorption of heat by the breaking of hydrogen bonds
E) water’s high surface tension
64) The bonds that are broken when water vaporizes are
A) ionic bonds.
B) hydrogen bonds between water molecules.
C) covalent bonds between atoms within water molecules.
D) polar covalent bonds.
E) nonpolar covalent bonds.
65) Which of the following is a hydrophobic material?
A) paper
B) table salt
C) wax
D) sugar
E) pasta
66) We can be sure that a mole of table sugar and a mole of vitamin C are equal in their
A) mass in daltons.
B) mass in grams.
C) volume.
D) number of atoms.
E) number of molecules.
67) Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration
of the lake?
A) 4.0 M
B) 10-10 M
C) 10-4 M
D) 104 M
E) 4%
68) Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration
of the lake?
A) 10-10 M
B) 10-4 M
C) 10-7 M
D) 10-14 M
E) 10 M
69) A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L
container of cold water, what would be the approximate increase in the temperature of the water? (Note:
A liter of cold water weighs about 1 kg.)
A) 50°C
B) 5°C
C) 1°C
D) 100°C
E) 10°C
70) How many grams of acetic acid (C2H4O2) would you use to make 10 L of a 0.1 M aqueous solution
of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen,
and 16 for oxygen.)
A) 10 g
B) 0.1 g
C) 6.0 g
D) 60 g
E) 0.6 g