Category: Analysis

Chemistry & Water

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Chemistry & Water
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Which of these is an example of an organelle?
a.
chloroplast
b.
muscle
c.
epidermis
d.
intestine
e.
maple leaf
 2.
Which of these is a correct representation of the hierarchy of biological organization from least to most complex?
a.
organelle of a stomach cell, digestive system, large intestine, small intestine, intestinal tissue, organism
b.
organelle of an intestinal cell, digestive system, small intestine, large intestine, intestinal tissue, organism
c.
molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism
d.
molecule, small intestine, large intestine, intestinal tissue, digestive system, organism
e.
molecule, digestive system, digestive cell organelle, small intestine, large intestine, intestinal cell, organism
 3.
As a result of photosynthesis, plants release ____ into the atmosphere.
a.
methane
b.
carbon dioxide
c.
water
d.
minerals
e.
oxygen
 4.
Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material?
a.
animal
b.
plant
c.
archaea
d.
A and B only
e.
A, B, and C
 5.
There are approximately ____ identified and named species.
a.
1,800
b.
180,000
c.
1,800,000
d.
18,000,000
e.
180,000,000
 6.
Prokaryotic and eukaryotic cells generally have which of the following features in common?
a.
a membrane-bounded nucleus
b.
a cell wall made of cellulose
c.
ribosomes
d.
flagella or cilia that contain microtubules
e.
linear chromosomes made of DNA and protein
 7.
Which of the following are characteristics shared by members of both domain Bacteria and domain Archaea?
a.
cytosol
b.
nucleus
c.
DNA
d.
A and C only
e.
A, B, and C
 8.
Two species belonging to the same genus must also belong to the same
a.
kingdom.
b.
phylum.
c.
class.
d.
order.
e.
all of the above
 9.
Which of the following is (are) true of natural selection?
a.
requires genetic variation
b.
results in descent with modification
c.
involves differential reproductive success
d.
B and C only
e.
A, B, and C
 10.
Which of these individuals is most likely to be successful in an evolutionary sense?
a.
a reproductively sterile individual who never falls ill
b.
an organism that dies after 5 days of life but leaves 10 offspring, all of whom survive to reproduce
c.
a male who mates with 20 females and fathers 1 offspring
d.
an organism that lives 100 years and leaves 2 offspring, both of whom survive to reproduce
e.
a female who mates with 20 males and produces 1 offspring
 11.
In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will
a.
remain unchanged.
b.
gradually decline.
c.
rapidly decline.
d.
gradually increase.
e.
rapidly increase.
 12.
The statement “If you show your dog affection, then your dog will seek your company” is an example of
a.
a statement that can be tested.
b.
a statement derived from a hypothesis.
c.
a prediction.
d.
deductive reasoning.
e.
all of the above
 13.
Which of the following is not a theme that unifies biology?
a.
interaction with the environment
b.
emergent properties
c.
evolution
d.
reductionism
e.
structure and function
 14.
Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have
a.
20 protons.
b.
40 electrons.
c.
40 neutrons.
d.
A and B only
e.
A, B, and C
 15.
The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon-14 contains ____ neutrons.
a.
6
b.
7
c.
8
d.
12
e.
14
 16.
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
a.
an electron may move to an electron shell farther out from the nucleus.
b.
an electron may move to an electron shell closer to the nucleus.
c.
the atom may become a radioactive isotope.
d.
the atom would become a positively charged ion, or cation.
e.
the atom would become a negatively charged ion, or anion.

Use the figure below to answer the following questions.

nar001-1.jpg

 17.
Which drawing depicts the electron configuration of nitrogen (N)?
a.
Drawing A
b.
Drawing B
c.
Drawing C
d.
Drawing D
e.
Drawing E
 18.
What does the reactivity of an atom depend on?
a.
number of valence shells in the atom
b.
number of orbitals found in the atom
c.
number of electrons in each orbital in the atom
d.
presence of unpaired electrons in the outer valence shell of the atom
e.
presence of hybridized orbitals in the atom

Use the information extracted from the periodic table in the figure below to answer the following questions.

nar002-1.jpg

 19.
How many electrons does phosphorus have in its valence shell?
a.
1
b.
2
c.
3
d.
4
e.
5
 20.
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
a.
Each hydrogen atom has a partial positive charge.
b.
The nitrogen atom has a strong positive charge.
c.
Each hydrogen atom has a slight negative charge.
d.
The nitrogen atom has a partial positive charge.
e.
There are covalent bonds between the hydrogen atoms.
 21.
What do the four elements most abundant in life-carbon, oxygen, hydrogen, and nitrogen-have in common?
a.
They all have the same number of valence electrons.
b.
Each element exists in only one isotopic form.
c.
They are equal in electronegativity.
d.
They are elements produced only by living cells.
e.
They all have unpaired electrons in their valence shells.

Use the figure below to answer the following questions. .

nar003-1.jpg

 22.
What results from the chemical reaction?
a.
a cation with a net charge of +1
b.
a cation with a net charge of -1
c.
an anion with a net charge of +1
d.
an anion with a net charge of -1
e.
A and D
 23.
The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
a.
MgCl
b.
MgCl2
c.
Mg2Cl
d.
Mg2Cl2
e.
MgCl3
 24.
Explains most specifically the attraction of water molecules to one another.
a.
nonpolar covalent bond
b.
polar covalent bond
c.
ionic bond
d.
hydrogen bond
e.
hydrophobic interaction
 25.
In a single molecule of water, the 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.
 26.
Which bonds must be broken for water to vaporize?
a.
ionic bonds
b.
nonpolar covalent bonds
c.
polar covalent bonds
d.
hydrogen bonds
e.
covalent bonds
 27.
The formation of ice during colder weather helps moderate the seasonal transition to winter. This is mainly because
a.
the breaking of hydrogen bonds absorbs heat.
b.
the formation of hydrogen bonds releases heat.
c.
the formation of hydrogen bonds absorbs heat.
d.
there is greater evaporative cooling of lakes.
e.
ice is denser than liquid water.
 28.
Recall that when 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 concentration of particles (molecules or ions)?
a.
0.5 M NaCl
b.
0.5 M glucose
c.
1.0 M NaCl
d.
1.0 M glucose
e.
1.0 M MgCl2

Use the figure below to answer the following questions:

nar004-1.jpg

 29.
How many grams of the molecule in the figure above would be required to make 1 L of a 0.5 M solution of the molecule?
(Carbon = 12, Oxygen = 16, Hydrogen = 1)
a.
29
b.
30
c.
60
d.
150
e.
342
 30.
Which of the following ionizes completely in solution and is considered to be a strong acid?
a.
NaOH
b.
HCl
c.
NH3
d.
H2CO3
e.
CH3COOH
 31.
Which of the following statements is completely correct?
a.
H2CO3 is a weak acid, and NaOH is a weak base.
b.
H2CO3 is a strong acid, and NaOH is a strong base.
c.
NH3 is a weak base, and H2CO3 is a strong acid.
d.
NH3 is a weak base, and HCl is a strong acid.
e.
NH3 is a strong base, and HCl is a weak acid.
 32.
Buffers are substances that help resist shifts in pH by
a.
releasing H+ in acidic solutions.
b.
donating H+ to a solution when they have been depleted.
c.
releasing OH- in basic solutions.
d.
accepting H+ when the are in excess.
e.
both B and D
 33.

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.

 

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Introduction and Chemistry

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Introduction and Chemistry
 

True/False
Indicate whether the statement is true or false.
 1.
The study of biology can help you better understand human reproduction.
 2.
Almost all organisms ultimately get their energy for survival from the sun.
 3.
All living things are composed of chemicals.
      nar001-1.jpg      nar001-2.jpg
 4.
Refer to the illustration above. Both species are multicellular.
 5.
Refer to the illustration above. Both species have DNA in their cells.
 6.
Refer to the illustration above. Reproduction ensures the ongoing success of both species.
 7.
Refer to the illustration above. The sand dollar and paramecium both show organization.
 8.
Refer to the illustration above. Unlike the sand dollar, the paramecium does not have to maintain a stable internal environment.
 9.
Scientists have not discovered any new species on Earth in more than 20 years.
 10.
A scientist who performs an experiment has no idea what the outcome of the experiment is going to be.
 11.
A theory is a hypothesis that has been proven true.
 12.
A theory is an assumption made by scientists and implies a lack of certainty.
 13.
Publication of the results of scientific investigations enables other scientists to verify these results.
 14.
Scientific investigations always follow a series of rigidly defined steps.
 15.
Resolution is a microscope’s power to increase an object’s apparent size.
 16.
The resolution power of an electron microscope is limited by the physical characteristics of light.
 17.
Units of time are not measured in metric units, so time measurements are not accepted for use with SI units.
 18.
The types of particles that are located in the nucleus of an atom are protons and neutrons, and the types of particles that are located in the energy levels surrounding the nucleus are electrons.
 19.
The atomic number of carbon is 6, so it must contain 12 electrons.
 20.
Most elements are stable if their outermost energy level contains an even number of electrons.
 21.
Atoms in a gas move more rapidly than atoms in a liquid or a solid do.
 22.
The products of an endergonic chemical reaction possess more energy than the reactants from which they are produced.
 23.
The amount of energy needed to cause a chemical reaction to start is called activation energy.
 24.
When an enzyme binds with its substrate, the activation energy needed for the chemical reaction to occur is raised.
 25.
Enzymes speed up a chemical reaction by increasing the activation energy of the reaction.
 26.
Without enzymes, chemical reactions necessary for life would not occur at a rate sufficient to sustain life.
 27.
Free hydrogen ions can react with water molecules and form a positively charged ion, the hydronium ion.
 28.
Bases tend to have a sour taste, while acids tend to have a bitter taste.
 29.
Buffers can neutralize acids, but they do not affect bases.
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 30.
Biology is the study of
a.
minerals.
c.
the weather.
b.
life.
d.
energy.
 31.
Instructions for development that are passed from parents to offspring are known as
a.
a species plan.
c.
genes.
b.
organ codes.
d.
natural selections.
 32.
Homeostasis means
a.
a change over long periods of time.
c.
rapid change.
b.
keeping things the same.
d.
the same thing as evolution.
 33.
Which of the following is a means by which heterotrophs can obtain energy?
a.
using water, carbon dioxide, and energy from the sun to produce sugars
b.
using water and carbon dioxide to produce energy-rich compounds
c.
consuming autotrophs
d.
consuming simple chemicals from the environment and using them to assemble complex chemicals and structures needed by the organism
 34.
Which of the following is not necessarily a distinct property of living things?
a.
homeostasis
c.
complexity
b.
metabolism
d.
reproduction
 35.
All organisms are composed of
a.
diatoms.
c.
cells.
b.
cellulose.
d.
None of the above
 36.
Scientific hypotheses are most often tested by the process of
a.
communicating.
c.
experimenting.
b.
inferring.
d.
analyzing data.
 37.
A unifying explanation for a broad range of observations is a
a.
hypothesis.
c.
prediction.
b.
theory.
d.
controlled experiment.
 38.
Most typically, the order in which the steps of the scientific method are applied is
a.
observations, predictions, hypothesis, controlled testing, theory, verification.
b.
predictions, observations, hypothesis, theory, controlled testing, verification.
c.
observations, hypothesis, predictions, controlled testing, theory, verification.
d.
observations, hypothesis, predictions, controlled testing, verification, theory.
 39.
Atoms are composed of
a.
protons with a positive charge.
c.
electrons with a negative charge.
b.
neutrons with no charge.
d.
All of the above
 40.
Which of the following states of matter contain(s) particles that are tightly linked together in a definite shape?
a.
solid
c.
gas
b.
liquid
d.
solid and liquid
 41.
The bond formed when two atoms share a pair of electrons is called a
a.
hydrogen bond.
c.
covalent bond.
b.
nonpolar bond.
d.
water bond.
 42.
An atom that has gained or lost electrons is called a(n)
a.
molecule.
c.
ion.
b.
nucleon.
d.
element.
 43.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
Atoms held together by ionic bonds separate when placed in water while atoms held together by covalent bonds do not separate in water.
b.
Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
 44.
A reaction in which the products have less energy than the reactants is
a.
an endergonic reaction.
c.
a filamentous reaction.
b.
an exergonic reaction.
d.
impossible.
nar002-1.jpg
 45.
Refer to the graph above. Which of these statements is true regarding the graph?
a.
Reaction “2” occurs faster than Reaction “3” because Reaction “2” requires more energy than Reaction “3.”
b.
The difference in the graphs shown for Reaction “2” and Reaction “3” is due to a difference in the activation energy needed for these reactions.
c.
Reactant “A” contains more energy at the beginning of the reaction than Product “C” has after the reaction.
d.
All of the above
nar003-1.jpg
 46.
Refer to the graphs above. Which graph illustrates what happens during an exergonic reaction?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs; they each show a different stage of an exergonic reaction.
d.
Neither graph shows an exergonic reaction.
 47.
Refer to the graphs above. Which graph illustrates a reaction during which reaction energy is released into the environment?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs, since all chemical reactions release energy into the environment
d.
Neither graph, since chemical reactions do not involve energy
 48.
Enzymes
a.
are able to heat up molecules so that they can react.
b.
provide CO2 for chemical reactions.
c.
are biological catalysts.
d.
absorb excess heat so that reactions occur at low temperatures.
 49.
A neutral solution has an equal number of
a.
hydrogen and hydronium ions.
c.
hydrogen and hydroxide ions.
b.
hydroxide and hydronium ions.
d.
oxygen and hydrogen ions.
 50.
Buffers
a.
are of relatively little importance in living things.
b.
are formed when a large number of hydroxide ions are released in a solution.
c.
are formed when a large number of hydronium ions are released in a solution.
d.
tend to prevent great fluctuations in pH.

 

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Chemistry Quiz

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Name: 

Chemistry

 

True/False
Indicate whether the sentence or statement is true or false.
1.
Two atoms having the same number of protons and electrons but different numbers of neutrons are called isotopes.
2.
The nucleus of an atom contains protons and electrons.
3.
A compound consists of atoms of two or more elements joined by chemical bonds.
4.
Energy can be converted from one form to another.
5.
The scale used for measuring the relative concentrations of hydrogen   ions and hydroxide ions in a solution is called the pH scale.
6.
Iron atoms and silver atoms have the same number of protons.
7.
An atom containing nine electrons can have three in its first energy level.
8.
Stable atoms need electrons to fill their outer energy levels.
9.
The types of particles that are located in the nucleus of an atom are protons and neutrons, and the types of particles that are located in the energy levels surrounding the nucleus are electrons.
10.
Buffers can neutralize acids, but they do not affect bases.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
11.
A solution that contains equal concentrations of hydrogen ions and hydroxide ions is a(n):
a.
neutral solution
c.
base
b.
acid
d.
compound
12.
The type of bond formed when two atoms share electrons is a(n):
a.
covalent bond
c.
elemental bond
b.
ionic bond
d.
homogeneous bond
13.
Carbon has an atomic number of 6. The number of energy levels in carbon is:
a.
1
c.
3
b.
2
d.
6
14.
In most elements, how many electrons are in the outer energy level of stable atoms?
a.
3
c.
8
b.
5
d.
12
15.
A solution with a pH of 9 has:
a.
an equal concentration of hydrogen and hydroxide ions
b.
a greater concentration of hydroxide ions than hydrogen ions
c.
a greater concentration of hydrogen ions than hydroxide ions
d.
a greater concentration of hydroxide ions than a solution with a pH of 10
16.
Carbon 12 and carbon 14 have the same number of protons and electrons, but they differ in the number of neutrons.  Therefore, they are:
a.
isometric
c.
icicles
b.
isotopes
d.
two different elements
17.
How many protons are in an atom that has a mass number of 23 and an atomic number of 11?
a.
11
c.
23
b.
12
d.
34
18.
Which of the following is matter?
a.
oxygen
c.
heat
b.
light
d.
all of these
19.
The subscript ‘2’ in H2 represents the number of:
a.
electrons
c.
ions
b.
molecules
d.
atoms
20.
The smallest unit of a compound that still retains the compound’s unique chemical properties is the:
a.
sol
c.
atom
b.
bond
d.
molecule
21.
Which of the following best describes a compound?
a.
atoms of one element that are chemically combined
b.
two or more elements combined chemically in a definite proportion
c.
atoms of the same element that have different mass numbers
d.
two or more atoms that are not combined chemically
22.
In a covalent bond, electrons are:
a.
shared
c.
lost
b.
gained
d.
transferred
23.
Which of the following pH values represents the most acidic condition?
a.
3
c.
10
b.
6
d.
14
24.
The main difference between covalent bonds and ionic bonds is that electrons:
a.
are shared in covalent bonds, but not in ionic bonds
b.
are shared in ionic bonds, but not in covalent bonds
c.
are shared in both, but at different times
d.
are involved only in covalent bonds
25.
Which of the following is the most common solvent in organisms?
a.
alcohol
c.
water
b.
lipids
d.
amino acids
26.
The bond formed when two atoms share a pair of electrons is called a
a.
hydrogen bond.
c.
covalent bond.
b.
nonpolar bond.
d.
water bond.
27.
The smallest particle of matter that can retain the chemical properties of carbon is
a.
a carbon molecule.
c.
a carbon atom.
b.
a carbon macromolecule.
d.
an element.
28.
All matter in the universe is composed of
a.
cells.
c.
atoms.
b.
molecules.
d.
carbon.
29.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
Atoms held together by ionic bonds separate when placed in water while atoms held together by covalent bonds do not separate in water.
b.
Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
      chp2_files/i0320000.jpg
30.
Refer to the graph above. Reaction “3” in the graph
a.
probably occurred in the presence of a catalyst.
b.
requires a greater activation energy than Reaction “2.”
c.
is the same as Reaction “1,” but faster.
d.
takes longer than Reaction “2.”
31.
Changing the course or pathway of a chemical reaction so that it requires less activation energy
a.
is a violation of the laws of nature.
b.
requires higher temperatures than those found within cells.
c.
occurs only when reactants are quickly added to the reaction mixture.
d.
is accomplished by the action of catalysts on reactants.
32.
A cell contains
a.
thousands of different kinds of enzymes, each promoting a different chemical reaction.
b.
one kind of enzyme that promotes thousands of different chemical reactions.
c.
approximately 100 kinds of enzymes, each promoting a different chemical reaction.
d.
one enzyme that promotes photosynthesis and one enzyme that promotes cellular respiration.
33.
The terms base and alkaline refer to solutions that
a.
contain dissolved sodium hydroxide.
b.
contain more hydronium ions than hydroxide ions.
c.
contain more hydroxide ions than hydronium ions.
d.
contain more hydroxide ions than hydrogen ions.
34.
Acidic solutions have a pH that is
a.
less than 7.
c.
a negative number.
b.
between 0 and 14.
d.
more than 7.
35.
Buffers
a.
are of relatively little importance in living things.
b.
are formed when a large number of hydroxide ions are released in a solution.
c.
are formed when a large number of hydronium ions are released in a solution.
d.
tend to prevent great fluctuations in pH.

 

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Chemistry Quiz

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Name: 

Chemistry

 

True/False
Indicate whether the sentence or statement is true or false.
1.
Two atoms having the same number of protons and electrons but different numbers of neutrons are called isotopes.
2.
The nucleus of an atom contains protons and electrons.
3.
A compound consists of atoms of two or more elements joined by chemical bonds.
4.
Energy can be converted from one form to another.
5.
The scale used for measuring the relative concentrations of hydrogen   ions and hydroxide ions in a solution is called the pH scale.
6.
Iron atoms and silver atoms have the same number of protons.
7.
An atom containing nine electrons can have three in its first energy level.
8.
Stable atoms need electrons to fill their outer energy levels.
9.
The types of particles that are located in the nucleus of an atom are protons and neutrons, and the types of particles that are located in the energy levels surrounding the nucleus are electrons.
10.
Buffers can neutralize acids, but they do not affect bases.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
11.
A solution that contains equal concentrations of hydrogen ions and hydroxide ions is a(n):
a.
neutral solution
c.
base
b.
acid
d.
compound
12.
The type of bond formed when two atoms share electrons is a(n):
a.
covalent bond
c.
elemental bond
b.
ionic bond
d.
homogeneous bond
13.
Carbon has an atomic number of 6. The number of energy levels in carbon is:
a.
1
c.
3
b.
2
d.
6
14.
In most elements, how many electrons are in the outer energy level of stable atoms?
a.
3
c.
8
b.
5
d.
12
15.
A solution with a pH of 9 has:
a.
an equal concentration of hydrogen and hydroxide ions
b.
a greater concentration of hydroxide ions than hydrogen ions
c.
a greater concentration of hydrogen ions than hydroxide ions
d.
a greater concentration of hydroxide ions than a solution with a pH of 10
16.
Carbon 12 and carbon 14 have the same number of protons and electrons, but they differ in the number of neutrons.  Therefore, they are:
a.
isometric
c.
icicles
b.
isotopes
d.
two different elements
17.
How many protons are in an atom that has a mass number of 23 and an atomic number of 11?
a.
11
c.
23
b.
12
d.
34
18.
Which of the following is matter?
a.
oxygen
c.
heat
b.
light
d.
all of these
19.
The subscript ‘2’ in H2 represents the number of:
a.
electrons
c.
ions
b.
molecules
d.
atoms
20.
The smallest unit of a compound that still retains the compound’s unique chemical properties is the:
a.
sol
c.
atom
b.
bond
d.
molecule
21.
Which of the following best describes a compound?
a.
atoms of one element that are chemically combined
b.
two or more elements combined chemically in a definite proportion
c.
atoms of the same element that have different mass numbers
d.
two or more atoms that are not combined chemically
22.
In a covalent bond, electrons are:
a.
shared
c.
lost
b.
gained
d.
transferred
23.
Which of the following pH values represents the most acidic condition?
a.
3
c.
10
b.
6
d.
14
24.
The main difference between covalent bonds and ionic bonds is that electrons:
a.
are shared in covalent bonds, but not in ionic bonds
b.
are shared in ionic bonds, but not in covalent bonds
c.
are shared in both, but at different times
d.
are involved only in covalent bonds
25.
Which of the following is the most common solvent in organisms?
a.
alcohol
c.
water
b.
lipids
d.
amino acids
26.
The bond formed when two atoms share a pair of electrons is called a
a.
hydrogen bond.
c.
covalent bond.
b.
nonpolar bond.
d.
water bond.
27.
The smallest particle of matter that can retain the chemical properties of carbon is
a.
a carbon molecule.
c.
a carbon atom.
b.
a carbon macromolecule.
d.
an element.
28.
All matter in the universe is composed of
a.
cells.
c.
atoms.
b.
molecules.
d.
carbon.
29.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
Atoms held together by ionic bonds separate when placed in water while atoms held together by covalent bonds do not separate in water.
b.
Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
      chp2_files/i0320000.jpg
30.
Refer to the graph above. Reaction “3” in the graph
a.
probably occurred in the presence of a catalyst.
b.
requires a greater activation energy than Reaction “2.”
c.
is the same as Reaction “1,” but faster.
d.
takes longer than Reaction “2.”
31.
Changing the course or pathway of a chemical reaction so that it requires less activation energy
a.
is a violation of the laws of nature.
b.
requires higher temperatures than those found within cells.
c.
occurs only when reactants are quickly added to the reaction mixture.
d.
is accomplished by the action of catalysts on reactants.
32.
A cell contains
a.
thousands of different kinds of enzymes, each promoting a different chemical reaction.
b.
one kind of enzyme that promotes thousands of different chemical reactions.
c.
approximately 100 kinds of enzymes, each promoting a different chemical reaction.
d.
one enzyme that promotes photosynthesis and one enzyme that promotes cellular respiration.
33.
The terms base and alkaline refer to solutions that
a.
contain dissolved sodium hydroxide.
b.
contain more hydronium ions than hydroxide ions.
c.
contain more hydroxide ions than hydronium ions.
d.
contain more hydroxide ions than hydrogen ions.
34.
Acidic solutions have a pH that is
a.
less than 7.
c.
a negative number.
b.
between 0 and 14.
d.
more than 7.
35.
Buffers
a.
are of relatively little importance in living things.
b.
are formed when a large number of hydroxide ions are released in a solution.
c.
are formed when a large number of hydronium ions are released in a solution.
d.
tend to prevent great fluctuations in pH.

 

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