Campbell’s Biology, 9e (Reece et al.)
Chapter 3 Water and Life
Life evolved in the ocean, and the chemistry of life occurs in an aqueous environment. These questions
explore the properties of water that are important to sustain life’s chemical processes, organismal
physiology, and interactions of organisms with their environment. Quantitative properties such as heat
content, molarity, and pH are also addressed. A few questions address how human activities affect the
global environment through acid rain and acidification of the ocean.
Multiple-Choice Questions
1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds.
D) ionic bonds.
E) van der Waals interactions.
2) The slight negative charge at one end of one water molecule is attracted to the slight positive charge
of another water molecule. What is this attraction called?
A) a covalent bond
B) a hydrogen bond
C) an ionic bond
D) a hydrophilic bond
E) a van der Waals interaction
3) The partial negative charge in a molecule of water occurs because
A) the oxygen atom acquires an additional electron.
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen
atom nucleus than around the hydrogen atom nucleus.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen
atoms.
D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.
4) Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to
carbon. Compared to water molecules, molecules of H2S
A) will ionize more readily.
B) will have greater cohesion to other molecules of H2S.
C) will have a greater tendency to form hydrogen bonds with each other.
D) will have a higher capacity to absorb heat for the same change in temperature.
E) will not form hydrogen bonds with each other.
5) Water molecules are able to form hydrogen bonds with
A) compounds that have polar covalent bonds.
B) oils.
C) oxygen gas (O2) molecules.
D) chloride ions.
E) any compound that is not soluble in water.
6) Which of the following effects is produced by the high surface tension of water?
A) Lakes don’t freeze solid in winter, despite low temperatures.
B) A water strider can walk across the surface of a small pond.
C) Organisms resist temperature changes, although they give off heat due to chemical reactions.
D) Evaporation of sweat from the skin helps to keep people from overheating.
E) Water flows upward from the roots to the leaves in plants.
7) Which of the following takes place as an ice cube cools a drink?
A) Molecular collisions in the drink increase.
B) Kinetic energy in the drink decreases.
C) A calorie of heat energy is transferred from the ice to the water of the drink.
D) The specific heat of the water in the drink decreases.
E) Evaporation of the water in the drink increases.
8) A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1
kilocalorie?
A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C
B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C
C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F
D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C
E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C
9) The nutritional information on a cereal box shows that one serving of a dry cereal has 200
kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be
sufficient to raise the temperature of 20 kg of water how many degrees Celsius?
A) 0.2°C
B) 1.0°C
C) 2.0°C
D) 10.0°C
E) 20.0°C
10) Liquid water’s high specific heat is mainly a consequence of the
A) small size of the water molecules.
B) high specific heat of oxygen and hydrogen atoms.
C) absorption and release of heat when hydrogen bonds break and form.
D) fact that water is a poor heat conductor.
E) higher density of liquid water than solid water (ice).
11) Which type of bond must be broken for water to vaporize?
A) ionic bonds
B) both hydrogen bonds and ionic bonds
C) polar covalent bonds
D) hydrogen bonds
E) both polar covalent bonds and hydrogen bonds
12) Temperature usually increases when water condenses. Which behavior of water is most directly
responsible for this phenomenon?
A) the change in density when it condenses to form a liquid or solid
B) reactions with other atmospheric compounds
C) the release of heat by the formation of hydrogen bonds
D) the release of heat by the breaking of hydrogen bonds
E) the high surface tension of water
13) Why does evaporation of water from a surface cause cooling of the surface?
A) The breaking of bonds between water molecules absorbs heat.
B) The water molecules with the most heat energy evaporate more readily.
C) The solute molecules left behind absorb heat.
D) Water molecules absorb heat from the surface in order to acquire enough energy to evaporate.
E) The expansion of water vapor extracts heat from the surface.
14) Why does ice float in liquid water?
A) The high surface tension of liquid water keeps the ice on top.
B) The ionic bonds between the molecules in ice prevent the ice from sinking.
C) Ice always has air bubbles that keep it afloat.
D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of
liquid water.
E) The crystalline lattice of ice causes it to be denser than liquid water.
15) Hydrophobic substances such as vegetable oil are
A) nonpolar substances that repel water molecules.
B) nonpolar substances that have an attraction for water molecules.
C) polar substances that repel water molecules.
D) polar substances that have an affinity for water.
E) charged molecules that hydrogen-bond with water molecules.
16) One mole (mol) of glucose (molecular mass = 180 daltons) is
A) 180 × 1023 molecules of glucose.
B) 1 kg of glucose dissolved in 1 L of solution.
C) the largest amount of glucose that can be dissolved in 1 L of solution.
D) 180 kilograms of glucose.
E) both 180 grams of glucose and 6.02 × 1023 molecules of glucose.
17) How many molecules of glucose (C6H12O6 molecular mass = 180 daltons) would be present in 90
grams of glucose?
A) 90 × 1023
B) (6.02/180) × 1023
C) (6.02/90) × 1023
D) (90 x 6.02) × 1023
E) (90/180) × 6.02 × 1023
18) How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M
glycerol solution?
A) 1 × 106
B) 14 × 6.02 × 1023
C) 92 × 6.02 × 1023
D) 6.02 × 1026
E) 6.02 × 1023
19) When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms
of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl–). In contrast, the
atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when
placed in aqueous solution. Which of the following solutions would be expected to contain the greatest
number of solute particles (molecules or ions)?
A) 1 L of 0.5 M NaCl
B) 1 L of 0.5 M glucose
C) 1 L of 1.0 M NaCl
D) 1 L of 1.0 M glucose
E) 1 L of 1.0 M NaCl and 1 L of 1.0 M glucose will contain equal numbers of solute particles.
20) The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to
make a 1 M solution of glucose?
A) Dissolve 1 g of glucose in 1 L of water.
B) Dissolve 180 g of glucose in 1 L of water.
C) Dissolve 180 g of glucose in 180 g of water.
D) Dissolve 180 milligrams (mg) of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the
solution is 1 L.
21) The molar mass of glucose (C6H12O6) is 180 g/mol. Which of the following procedures should you
carry out to make a 0.5 M solution of glucose?
A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume
of solution is 1 L.
B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume
of the solution is 1 L.
C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume
of the solution is 1 L.
D) Dissolve 0.5 g of glucose in 1 L of water.
E) Dissolve 180 g of glucose in 0.5 L of water.
22) You have a freshly prepared 0.1 M solution of glucose in water. Each liter of this solution contains
how many glucose molecules?
A) 6.02 × 1023
B) 3.01 × 1023
C) 6.02 × 1024
D) 12.04 × 1023
E) 6.02 × 1022
23) The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? (Hint:
What is the mass of 1 liter of pure water?)
A) 55.6 M
B) 18 M
C) 37 M
D) 0.66 M
E) 1.0 M
24) You have a freshly prepared 1 M solution of glucose in water. You carefully pour out a 100 mL
sample of that solution. How many glucose molecules are included in that 100 mL sample?
A) 6.02 × 1023
B) 3.01 × 1023
C) 6.02 × 1024
D) 12.04 × 1023
E) 6.02 × 1022
25) A strong acid like HCl
A) ionizes completely in an aqueous solution.
B) increases the pH when added to an aqueous solution.
C) reacts with strong bases to create a buffered solution.
D) is a strong buffer at low pH.
E) both ionizes completely in aqueous solutions and is a strong buffer at low pH.
26) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
A) NaCl
B) HCl
C) NH3
D) H2CO3
E) NaOH
27) A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
A) It is a strong acid that ionizes completely in water.
B) It is a strong base that ionizes completely in water.
C) It is a weak acid.
D) It is a weak base.
E) It is neither an acid nor a base.
28) A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the
following best describes this solution?
A) acidic: will accept H+ from both strong and weak acids
B) basic: will accept H+ from both strong and weak acids
C) acidic: will give H+ to weak acids, but accept H+ from strong acids
D) basic: will give H+ to weak acids, but accept H+ from weak acids
E) acidic: will give H+ to both strong and weak acids
29) A solution contains 0.0000001(10-7) moles of hydroxyl ions [OH–] per liter. Which of the following
best describes this solution?
A) acidic: H+ acceptor
B) basic: H+ acceptor
C) acidic: H+ donor
D) basic: H+ donor
E) neutral
30) What is the pH of a solution with a hydroxyl ion [OH–] concentration of 10-12 M?
A) pH 2
B) pH 4
C) pH 10
D) pH 12
E) pH 14
31) What is the pH of a 1 millimolar NaOH solution?
A) pH 3
B) pH 8
C) pH 9
D) pH 10
E) pH 11
32) Which of the following solutions would require the greatest amount of base to be added to bring the
solution to neutral pH?
A) gastric juice at pH 2
B) vinegar at pH 3
C) tomato juice at pH 4
D) black coffee at pH 5
E) household bleach at pH 12
33) What is the hydrogen ion [H+] concentration of a solution of pH 8?
A) 8 M
B) 8 x 10-6 M
C) 0.01 M
D) 10-8 M
E) 10-6 M
Answer: D
Topic: Concept 3.3
Skill: Knowledge/Comprehension
34) If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9.
B) concentration of H+ has increased tenfold (10X) compared to what it was at pH 9.
C) concentration of OH– has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH– has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H+ has increased tenfold (10X) and the concentration of OH– has decreased to one-
tenth (1/10) what they were at pH 9.
35) If the pH of a solution is increased from pH 5 to pH 7, it means that the
A) concentration of H+ is twice (2X) what it was at pH 5.
B) concentration of H+ is one-half (1/2) what it was at pH 5.
C) concentration of OH– is 100 times greater than what it was at pH 5.
D) concentration of OH– is one-hundredth (0.01X) what it was at pH 5.
E) concentration of H+ is 100 times greater and the concentration of OH– is one-hundredth what they
were at pH 5.
36) One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH
6?
A) 4 times more
B) 16 times more
C) 40,000 times more
D) 10,000 times more
E) 100,000 times more
37) One liter of a solution of pH 9 has how many more hydroxyl ions (OH–) than 1 L of a solution of pH
4?
A) 5 times more
B) 32 times more
C) 50,000 times more
D) 10,000 times more
E) 100,000 times more
38) Which of the following statements is true about buffer solutions?
A) They maintain a constant pH when bases are added to them but not when acids are added to them.
B) They maintain a constant pH when acids are added to them but not when bases are added to them.
C) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to
them.
D) They maintain a relatively constant pH when either acids or bases are added to them.
E) They are found only in living systems and biological fluids.
39) Buffers are substances that help resist shifts in pH by
A) releasing H+ to a solution when acids are added.
B) donating H+ to a solution when bases are added.
C) releasing OH– to a solution when bases are added.
D) accepting H+ from a solution when acids are added.
E) both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
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40) One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3).
Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3–) and a hydrogen ion (H+).
Thus,
H2CO3 ↔ HCO3– + H+
If the pH of the blood drops, one would expect
A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3–.
B) the concentration of hydroxide ion (OH–) to increase.
C) the concentration of bicarbonate ion (HCO3–) to increase.
D) the HCO3– to act as a base and remove excess H+ with the formation of H2CO3.
E) the HCO3– to act as an acid and remove excess H+ with the formation of H2CO3.
41) One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3).
Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion
(HCO3– and a hydrogen ion (H+). Thus,
H2CO3 ↔ HCO3– + H+
If the pH of the blood increases, one would expect
A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3–.
B) an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3–.
C) a decrease in the concentration of HCO3– and an increase in the concentration of H+.
D) an increase in the concentration of HCO3– and a decrease in the concentration of OH–.
E) a decrease in the concentration of HCO3– and an increase in the concentration of both H2CO3 and
H+.
42) Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion
concentration of this lake?
A) 1 × 10-10 mol of hydroxyl ion per liter of lake water
B) 1 × 10-4 mol of hydroxyl ion per liter of lake water
C) 10.0 M with regard to hydroxyl ion concentration
D) 4.0 M with regard to hydroxyl ion concentration
E) 1 × 10-4 mol of hydroxyl ion per liter of lake water and 4.0 M with regard to hydrogen ion
concentration
43) Research indicates that acid precipitation can damage living organisms by
A) buffering aquatic systems such as lakes and streams.
B) decreasing the H+ concentration of lakes and streams.
C) increasing the OH– concentration of lakes and streams.
D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant
growth.
E) both decreasing the H+ concentration of lakes and streams and increasing the OH– concentration of
lakes and streams.
44) Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information,
we can reasonably conclude that
A) solution Y has no free hydrogen ions (H+).
B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen
ions in solution Y.
C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of
hydrogen ions in solution X.
D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen
ions in solution Y.
E) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of
hydrogen ions in solution Y.
45) If a solution has a pH of 7, this means that
A) there are no H+ ions in the water.
B) this is a solution of pure water.
C) the concentration of H+ ions in the water equals the concentration of OH– ions in the water.
D) this is a solution of pure water, and the concentration of H+ ions in the water is 10-7 M.
E) this is a solution of pure water, and the concentration of H+ ions equals the concentration of OH– ions
in the water.