54. Which of the following would have the most difficulty entering a water lattice?
a.
table salt (NaCl)
b.
a nonpolar molecule
c.
a sodium ion
d.
a proton (H+)
e.
an electron
55. Ice floats in liquid water because
a.
ice forms hydrogen bonds with the surface of liquid water.
b.
ice forms hydrogen bonds but liquid water does not.
c.
the hydrogen bonds of liquid water are fixed in place.
d.
liquid water forms hydrogen bonds but ice does not.
e.
the distance between water molecules is maximized due to the hydrogen bonds which are
fixed in place.
56. Biological membranes are held together mainly by
a.
hydrogen bonds between lipid molecules.
b.
hydration layers over lipid molecules.
c.
exclusion of the nonpolar regions of lipids by water.
d.
hydrogen bonds between water molecules.
e.
surface tension at the interface between layers of water molecules.
57. A ____ is formed when a ____ is dissolved in a ____.
a.
solution; solute; solvent
b.
solute; solvent; solution
c.
solution; solvent; solute
d.
solvent; solution; solute
e.
solvent; solute; solution
58. When sugar dissolves in water, water is acting as a ____ and the sugar molecules are acting as ____.
a.
solution; solvents
b.
solute; solutions
c.
solvent; solutes
d.
solute; solvents
e.
solvent; solutions
59. When salt dissolves in water as illustrated in the figure above, the water molecules form ____ around
the Na+ and Cl− ions.
a.
covalent bonds
b.
hydration layers
c.
nonpolar interactions
d.
membranes
e.
ionic bonds
60. Water has a molecular weight of 18 g per mole, and glucose has a molecular weight of 180 g per mole.
Which of the following would have an approximately equal number of water and glucose molecules?
a.
1 g of water and 180 g of glucose
b.
90 g of water and 9 g of glucose
c.
180 g of water and 1 g of glucose
d.
9 g of water and 90 g of glucose
e.
90 g of water and 90 g of glucose
61. Water has an unusually high boiling point for its molecular weight because water molecules
a.
are very dense.
b.
get much heavier as they are heated.
c.
are held to each other by hydrogen bonds.
d.
are held together by covalent bonds.
e.
form hydration layers.
62. The hydrogen-bond lattice causes water to have an unusually ____ specific heat and an unusually ____
heat of vaporization for its molecular weight.
a.
high; high
b.
low; high
c.
high; low
d.
low; low
63. Water is useful for cooling organisms mainly due to its
a.
hydration layers.
b.
specific heat.
c.
low calories.
d.
surface tension.
e.
heat of vaporization.
64. Water has an important stabilizing effect on temperature in living organisms and their environments
because as water absorbs heat, much of the energy is used to ____ instead of raising the temperature.
a.
create hydrogen bonds
b.
create covalent bonds
c.
break surface tension
d.
break hydrogen bonds
e.
create hydration layers
65. The water strider shown in the figure above is able to stand on water because of the ____ of water.
a.
covalent bonds
b.
surface tension
c.
van der Waals forces
d.
density
e.
hydration layer
66. When added to water, a base will act as a(n) ____ and cause the pH of the solution to ____.
a.
proton acceptor; rise
b.
proton donor; rise
c.
proton acceptor; fall
d.
proton donor; fall
e.
acid; fall
67. When added to water at neutral pH (7.0), an acid will
a.
act as a proton donor, raising the pH of the solution.
b.
act as a proton acceptor, raising the pH of the solution.
c.
act as a proton donor, lowering the pH of the solution.
d.
act as a proton acceptor, lowering the pH of the solution.
e.
do nothing since the aqueous solution is neutral.
68. A pH of 6 is ____ times more ____ than a pH of 2.
a.
3; acidic
b.
4; acidic
c.
3; basic
d.
10,000; basic
e.
40; basic
69. For pure water, which has a pH of 7.0, which of the following is true?
a.
[H+] < [OH−]
b.
[H+] = [OH−]
c.
[H+] = 0
d.
[OH−] = 0
e.
[H+] > [OH−]
70. For acid rainwater, which has a pH as low as 3.0, which of the following is true?
a.
[H+] < [OH−]
b.
[H+] = [OH−]
c.
[H+] = 0
d.
[OH−] = 0
e.
[H+] > [OH−]
71. Solution A has a pH of 6 and solution B has a pH of 8. Which of the following is true regarding the
concentration of hydrogen ions in each solution?
a.
A has 100 times greater H+ concentration than B.
b.
B has 100 times greater H+ concentration than A.
c.
A has 7/9 of the H+ concentration of B.
d.
A has 9/7 of the H+ concentration of B.
e.
A has 1,000 times greater H+ concentration than B.
72. In water, NaOH almost completely separates into Na+ and OH– ions. Thus, NaOH is _____.
a.
a strong acid
b.
a strong base
c.
a weak acid
d.
a weak base
e.
neutral
73. Seawater typically is
a.
highly basic.
b.
neutral.
c.
somewhat basic.
d.
somewhat acidic.
e.
highly basic.
74. Without ____, living organisms would often experience major changes in pH in their cells.
a.
buffers
b.
acids
c.
surface tension
d.
nonpolar bonds
e.
bases
75. Most pH buffers are
a.
strong acids.
b.
weak acids or weak bases.
c.
weak acids.
d.
strong bases.
e.
strong acids or strong bases.
76. A research group led by Li Li has found a(n) ____ that potentially can be used in uranium
bioremediation.
a.
amoeba
b.
plant
c.
alga
d.
bacterium
e.
fungus
77. The most common isotope of carbon has an atomic number of 6 and a mass number of 12, while the
most common isotope of oxygen has an atomic number of 8 and a mass number of 16. A molecule of
CO2 made up of these common isotopes has a molecular weight of ____.
a.
28
b.
44
c.
56
d.
14
e.
22
39
78. The water lattice illustrated in the figure above forms as a result of ____ between water molecules.
a.
covalent bonds
b.
hydrogen bonds
c.
nonpolar interactions
d.
ionic bonds
e.
van der Walls forces
MATCHING
Match each of the following terms with its correct definition.
a.
Anything that occupies space and has mass
b.
A pure substance that cannot be broken down into simpler substances by ordinary
chemical or physical techniques
c.
An atom with the same number of protons as another atom but a different number of
neutrons
d.
The locations around an atomic nucleus where an electron occurs most frequently
e.
A molecule whose component atoms are different from each other
79. element
80. compound
81. matter
82. orbital
83. isotope
For each of the following situations, choose the correct type of chemical bond.
a.
ionic bond(s)
b.
nonpolar covalent bond(s)
c.
polar covalent bond(s)
d.
hydrogen bond(s)
e.
van der Waals forces
84. Occurs when electrons are shared equally between two atoms
85. Used by geckos for clinging to and climbing up smooth vertical surfaces
86. Formed by the attraction between partial positive and partial negative charges created by unequal
electron sharing
87. Occurs in sodium chloride (NaCl)
88. The weakest of the chemical linkages listed
89. Occurs in a water molecule (H2O)
90. Characteristic of molecules that contain atoms of only one kind
91. Forms when atoms gain or lose valence electrons completely
92. Attraction that arises when the constant movement of electrons, by chance, produces temporary zones
of partial positive and partial negative charges
93. Occurs when electrons are shared unequally between two atoms
94. Creates a region that is hydrophobic
95. Occurs between water molecules
96. Occurs in molecular oxygen (O2)
SHORT ANSWER
97. Why is iodine considered a trace element that is vital for biological function in humans?
98. Place a large amount of hydrogen gas and oxygen gas in the presence of a fire and you will get an
explosion. In light of this, explain how it is possible that water, which is composed of hydrogen and
oxygen, is often used to put out fires.
99. How could you use 14C to deduce the overall reaction of photosynthesis?
100. If van der Waals forces are weak, how can geckos utilize these forces to cling to and walk up vertical
smooth surfaces?
101. Describe the difference between cohesion and adhesion, and how they combine to allow water to move
upward in plants.
MODIFIED TRUE/FALSE
If the statement is true, answer “T”. If the statement is false, answer “F” and make it correct by
changing the underlined word(s) and writing the correct word(s) in the answer blank(s).
102. An understanding of the relationship between the structure of elemental substances and their behavior
is the first step in learning biology.
103. Carbon dioxide is an element.
104. Atoms with atomic numbers between lithium and neon have two energy levels.
105. Radioactivity can destroy cancerous tissue but not healthy tissue.
106. Polar molecules that associate readily with carbon dioxide are hydrophilic.
107. A typical candy bar has approximately 250,000 Calories.
108. Vinegar is a good cleaning solution because it is a weak acid, while ammonia is a good cleaner
because it is a weak base.
109. The metabolism of some bacteria transforms uranium from its soluble form to an insoluble form.
ESSAY
110. Oxygen generally forms two covalent bonds, while carbon generally forms four covalent bonds. In
contrast, helium is inert (generally does not form any bonds). Explain the reason for the differences in
chemical behavior between these three elements.
111. Describe how the interaction of water with dual polarity lipid molecules establishes biological
membranes.