1.
| |
Why are biologists so interested in chemistry? (2.0) |
|
Chemicals are the fundamental parts of all living things. |
|
Most chemicals are harmful to living things. |
|
They know little about life except the chemicals it is made from. |
|
If you understand the chemistry of life, you can make a lot of
money. |
|
Everything about life can be known by understanding its chemistry. |
|
2.
| |
Someone who attempts to understand the functioning of the brain by studying individual brain cells is taking a(n) _____
approach (2.1) |
|
emergent |
|
reductionist |
|
organelle |
|
holistic |
|
none of the above |
|
3.
| |
There are _____ naturally occurring elements. (2.2) |
|
92 |
|
45 |
|
230 |
|
25 |
|
108 |
|
4.
| |
K is the chemical symbol for __________ and P is the symbol for __________. (2.2)
|
|
phosphorus ... sodium |
|
sodium ... potassium |
|
potassium ... phosphorus |
|
magnesium ... phosphorus |
|
iron ... potassium |
|
5.
| |
Which one of the following is NOT one of the four most common elements found in living systems? (2.2) |
|
H |
|
N |
|
C |
|
Ne |
|
all of the above |
|
6.
| |
A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____. (2.2) |
|
molecule |
|
element |
|
compound |
|
buffer |
|
cell |
|
7.
| |
Which of the following statements is true about compounds? (2.3) |
|
Twenty-five compounds are essential to life. |
|
They are smaller than any one element. |
|
They have polarity. |
|
They contain two or more elements in a fixed ratio to each other. |
|
All of the above. |
|
8.
| |
Which of the following is the smallest in volume? (2.4) |
|
the nucleus of an oxygen atom |
|
a water molecule |
|
a proton |
|
an ice crystal |
|
the electron cloud of an oxygen atom |
|
9.
| |
Which one of the following has negligible mass? (2.4) |
|
proton |
|
neutron |
|
electron |
|
atom |
|
element |
|
10.
| |
Which one of the following subatomic particles has appreciable mass and lacks a charge? (2.4) |
|
proton |
|
neutron |
|
electron |
|
element |
|
molecule |
|
11.
| |
The number of protons in an uncharged atom _____. (2.4) |
|
equals the number of electrons |
|
equals the number of neutrons |
|
varies with the different isotopes |
|
equals the number of electrons in the outer orbital of the atom |
|
determines its mass number |
|
12.
| |
Consider a hypothetical atom with an atomic number of 4 and a net electronic charge of +1. It has 4 protons. How many neutrons
does this atom have? (2.4) |
|
2 |
|
4 |
|
8 |
|
The answer cannot be determined from the information. |
|
none of the above |
|
13.
| |
A particular carbon isotope has an atomic number of 6 and an atomic weight of 14. The respective number of neutrons, protons,
and electrons it has is _____. (2.4) |
|
6, 8, 6 |
|
6, 6, 8 |
|
8, 6, 6 |
|
8, 6, 8 |
|
8, 6, 4 |
|
14.
| |
An element has 8 protons, 9 neutrons, and 8 electrons. Its atomic number and its mass number, respectively, are _____.
(2.4) |
|
8 and 16 |
|
8 and 17 |
|
9 and 16 |
|
9 and 17 |
|
16 and 8 |
|
15.
| |
Two atoms of the same element must have the same number of _____. (2.4) |
|
neutrons |
|
protons |
|
electrons |
|
neutrons plus protons |
|
protons plus electrons |
|
16.
| |
An uncharged atom of nitrogen (atomic number = 7) has ___________. (2.4)
|
|
7 neutrons |
|
7 protons and 7 neutrons |
|
7 neutrons and 7 electrons |
|
7 protons and 7 electrons |
|
7 valence electrons |
|
17.
| |
Isotopes of an element will always differ in _____. (2.4) |
|
atomic number |
|
atomic mass number |
|
number of electrons |
|
all of the above |
|
none of the above |
|
18.
| |
Phosphorus–32 (radioactive) has __________ than phosphorus–35 (normal). (2.4) |
|
3 more neutrons |
|
3 more protons |
|
3 fewer neutrons |
|
3 fewer protons |
|
three more atoms |
|
19.
| |
The most common form of calcium has 20 protons, 20 neutrons, and 20 electrons. Which of the following elements would be
an isotope of calcium? (2.4) |
|
an atom with 21 protons, 20 neutrons, and 21 electrons |
|
an atom with 20 protons, 20 neutrons, and 18 electrons |
|
an atom with 20 protons, 21 neutrons, and 20 electrons |
|
none of the above |
|
all of the above |
|
20.
| |
Which one of the following always has a positive charge? (2.4) |
|
proton |
|
neutron |
|
electron |
|
atom |
|
element |
|
21.
| |
Changing the number of _____ would change an atom into an atom of a different element. (2.4) |
|
bonds formed by an atom |
|
electrons circling the nucleus of an atom |
|
protons in an atom |
|
particles in the nucleus of an atom |
|
neutrons in an atom |
|
22.
| |
Which of the following is NOT a characteristic that makes radioactive tracers useful in medical diagnoses and clinical
research? (2.5) |
|
They are incorporated into reactions in living material. |
|
They are easily detectable in minute amounts. |
|
They damage or destroy molecules. |
|
Living cells cannot distinguish them from nonradioactive isotopes. |
|
They can be used with PET scanners. |
|
23.
| |
Researchers studying the effects of toxic wastes knew that animals were poisoned by the heavy metal cadmium, but they wanted
to know where cadmium accumulated in the body. They could find out by _____. (2.5)
|
|
tracing the movement of cadmium isotopes in test animals |
|
measuring the size of cadmium atoms |
|
finding out whether cadmium atoms form ionic or covalent bonds |
|
finding out whether cadmium is acidic in water |
|
determining the number of bonds formed by cadmium atoms |
|
24.
| |
The chemical bonding and reactivity characteristics of an element depend mostly on the _____. (2.6) |
|
number of electrons in its outer shell |
|
number of electron shells present in the atoms |
|
mean energy level of its electrons |
|
degree to which it has more or fewer electrons than protons |
|
number of protons plus the number of neutrons |
|
25.
| |
Some groups of elements react chemically in similar ways. For example, the chemical reactions of sodium and the chemistry
of lithium are similar, as are the chemistries of chlorine and iodine. These similar chemistries are caused when different
elements have similar ___________. (2.6) |
|
atomic size |
|
numbers of outer-shell electrons |
|
numbers of electrons |
|
energy content per electron |
|
atomic number |
|
26.
| |
For most atoms, a stable configuration of electrons is attained when the atom ___________. (2.6) |
|
has as many protons as neutrons |
|
has moved all its electrons to its outermost shell |
|
achieves a zero net charge |
|
has 8 electrons in its outermost shell |
|
none of the above |
|
27.
| |
Atomic oxygen has an atomic number of 8. It has __________ electrons in its outermost electron shell. (2.6) |
|
2 |
|
6 |
|
8 |
|
10 |
|
none of the above |
|
28.
| |
An atom that normally has _____ in its outer shell would tend not to form chemical bonds with other atoms. (2.6) |
|
1 electron |
|
3 electrons |
|
4 electrons |
|
6 electrons |
|
8 electrons |
|
29.
| |
When the proton number and electron number are unequal, the atom or molecule _____. (2.7) |
|
forms a covalent bond with another atom |
|
is an ion |
|
is an isotope. |
|
gains or loses a proton |
|
gains or loses a neutron |
|
30.
| |
A sodium atom has a mass number of 23. Its atomic number is 11. How many electrons does it have if it is not an ion? (2.7) |
|
11 |
|
12 |
|
22 |
|
23 |
|
34 |
|
31.
| |
Fluorine atoms tend to take electrons from any atoms that come near. As a result, fluorine atoms _____. (2.7) |
|
tend to become positively charged |
|
are nonpolar |
|
do not react readily with other atoms |
|
tend to form ionic bonds |
|
are not very electronegative |
|
32.
| |
Ionic bonds form as a result of ___________. (2.7) |
|
attraction between atoms that have opposite charges |
|
attraction between hydrogen and other atoms that share electrons
unequally |
|
sharing of electron pairs between atoms |
|
sharing of single electrons between atoms |
|
the motion of electrons |
|
33.
| |
Which of these describes a covalent bond? (2.8) |
|
Two or more atoms share electron pairs. |
|
It involves an atom that gains an electron. |
|
Molecules linked by covalent bonds are less dense when in solid
form than when in liquid form. |
|
A hydrogen atom with a partial positive charge is attracted to
another atom with a partial negative charge. |
|
It involves an atom that loses an electron. |
|
34.
| |
A polar covalent bond is a bond that _____. (2.9) |
|
is found only in H2O |
|
is found only in molecules containing oxygen |
|
shares electrons equally between atoms |
|
ionizes |
|
has shared electrons pulled closer to the more electronegative
atom, thereby producing slight charges on the molecule. |
|
35.
| |
Which is NOT involved in, or is NOT relevant to, hydrogen bonding? (2.9)
|
|
hoarding of electrons by one atom more than another |
|
electronegativity |
|
attraction between unlike partial charges |
|
loss of electrons |
|
polar molecules |
|
36.
| |
Hydrogen bonds occur when ___________. (2.9) |
|
a molecule with partial charges contacts a molecule without partial
charges |
|
a molecule with a low molecular weight is completely enclosed
in a molecule with high molecular weight |
|
two atoms achieve stable electron configurations by sharing electrons
with each other |
|
partial opposite charges on molecules come close enough to attract
each other |
|
none of the above |
|
37.
| |
A covalent bond is likely to be polar if _____. (2.9) |
|
the two atoms sharing electrons are equally electronegative |
|
one of the atoms sharing electrons is much more electronegative |
|
it is between two atoms that are both very strong electron acceptors |
|
the two atoms sharing electrons are of the same element |
|
it is between two atoms that are both very strong electron donors |
|
38.
| |
In a group of water molecules, hydrogen bonds form between _____. (2.9) |
|
two hydrogen atoms in different water molecules |
|
the oxygen atoms in different water molecules |
|
the oxygen atom in one molecule and a hydrogen atom in another
molecule |
|
the hydrogen atoms in a single water molecule |
|
none of the above |
|
39.
| |
The partial charges on a water molecule occur because of _____. (2.9) |
|
the unequal sharing of electrons between hydrogen and oxygen |
|
the achievement of a stable configuration by one atom of a bond
but not by the other partner |
|
covalent bonding |
|
ionic bonding |
|
the high electronegativity of hydrogen |
|
40.
| |
Water is a polar molecule. This means that _____. (2.9) |
|
the opposite ends of the molecule have opposite charges |
|
water molecules are linear, like a pole |
|
water is one of the many nonpolar molecules |
|
the atoms in water have equal electronegativities |
|
all of the above |
|
41.
| |
A hydrogen bond ___________. (2.10) |
|
is one in which two hydrogens bond to each other |
|
is one in which hydrogen is strongly attracted to a positively
charged atom |
|
is a function of nonpolar interactions |
|
is weak |
|
is one of the strongest bonds known |
|
42.
| |
Water molecules have a polarity that allows them to bond to each other with loose bonds called _____. (2.10) |
|
hydrogen bonds |
|
ionic bonds |
|
acid bonds |
|
nonpolar bonds |
|
none of the above |
|
43.
| |
What do cohesion and surface tension have in common with reference to water? (2.11)
|
|
All are results of the structure of the hydrogen atom. |
|
All are produced by covalent bonding. |
|
All are properties related to hydrogen bonding. |
|
All have to do with ionic interactions. |
|
All are aspects of a crystalline structure. |
|
44.
| |
The tendency of water molecules to stick together _____. (2.11) |
|
provides the surface tension that allows some insects to walk
on water |
|
is called cohesion |
|
keeps water moving through the vessels in a tree trunk |
|
acts to moderate temperature |
|
all of the above |
|
45.
| |
Water resists temperature change because _____. (2.12) |
|
large bodies of water cannot store heat |
|
heating water absorbs energy by disrupting the hydrogen bonds
before evaporation can occur |
|
evaporation of water heats the surface it leaves |
|
hydrogen bonding increases water's ability to vaporize |
|
none of the above |
|
46.
| |
Because the molecules of water are farther apart in ice than in liquid water, _____. (2.13) |
|
ice floats |
|
ice is denser than liquid water |
|
ice expands when it melts |
|
ice vaporizes before liquid water does |
|
all of the above |
|
47.
| |
Cells are surrounded by water, and cells themselves are about 70-95% water. As a result, _____. (2.14) |
|
the temperature of living things tends to change relatively slowly |
|
a variety of nutrient molecules are readily available as dissolved
solutes |
|
waste products produced by cell metabolism can be easily removed |
|
dissolved substances can be easily transported within the cell,
or between cells in multicellular organisms |
|
all of the above |
|
48.
| |
The most widely effective solvent for organisms is a material that is _____. (2.14)
|
|
polar |
|
nonpolar |
|
ionic |
|
pigmented |
|
volatile |
|
49.
| |
Sodium chloride (NaCl) dissolves in water because water molecules _____. (2.14)
|
|
have a high specific heat |
|
lose electrons |
|
are polar |
|
have a pH near 7 |
|
are less dense than NaCl molecules |
|
50.
| |
Adding acid to a solution ____.(2.15) |
|
increases the hydrogen ion concentration and raises the pH |
|
increases the hydrogen ion concentration and lowers the pH |
|
decreases the hydrogen ion concentration and raises the pH |
|
decreases the hydrogen ion concentration and lowers the pH |
|
either increases or decreases the pH, depending on the original
acidity |
|
51.
| |
Which of the following dissociations is that of an acid? (2.15) |
|
H2O --> H+ + OH- |
|
NaOH --> Na+ + OH- |
|
HF --> H+ + F- |
|
NH3 + H+ --> NH4+ |
|
HCO3- + H+ --> H2CO3 |
|
52.
| |
A glass of grapefruit juice, at pH 3, contains _____ H+ as a glass of tomato juice, at pH 4. (2.15) |
|
one-tenth as much |
|
half as much |
|
twice as much |
|
three times as much |
|
ten times as much |
|
53.
| |
An acid is _____. (2.15) |
|
any compound with a pH |
|
any compound that accepts hydrogen ions |
|
a material that resists pH changes |
|
a compound that donates hydrogen ions to a solution |
|
a solution with a pH between 7 and 14 |
|
54.
| |
Something that resists a change in pH is called a(n) _____. (2.15) |
|
isoproton |
|
buffer |
|
proton sink |
|
acid |
|
base |
|
55.
| |
Adding a base tends to _____ of a solution. (2.15) |
|
lower hydrogen ion concentration and lower the pH |
|
lower hydrogen ion concentration and increase the pH |
|
increase hydrogen ion concentration and lower the pH |
|
increase the hydrogen ion concentration and increase the pH |
|
lower the hydroxide ion concentration and lower the pH |
|
56.
| |
Pure water has a pH of 7, but acid precipitation has a pH close to 3. This means that acid rain has a concentration of
hydrogen ions that is __________ times the hydrogen ion concentration of pure water. (2.15) |
|
0.0001 |
|
0.25 |
|
4 |
|
10,000 |
|
-4 |
|
57.
| |
A pH of 6 is how many times more acidic than a pH of 9? (2.15) |
|
300 |
|
1,000 |
|
3 |
|
100 |
|
none of the above |
|
58.
| |
Select the statement that best describes a buffer. (2.15) |
|
A buffer accepts hydrogen ions when they are in excess and donates
hydrogen ions when they have been depleted. |
|
A buffer causes acidic solutions to become alkaline, and alkaline
solutions to become acidic. |
|
A buffer prevents the pH of a solution from changing when an
acid or base is added. |
|
A buffer stabilizes the pH of a solution by preventing acids
or bases from dissociating. |
|
Buffered solutions are always neutral, with a pH of 7. |
|
59.
| |
Which of the following statements is true about acid precipitation? (2.16)
|
|
It can be eliminated if we burn fossil fuels instead of using
solar or nuclear power. |
|
It affects bodies of water but has little effect on the land. |
|
It has the most pronounced effect on lakes and streams in the
early spring. |
|
Building taller smokestacks can clean it up. |
|
None of the above. |