Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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A
change in color, such as rusting of metal, is a sign that a. | a chemical
change is taking place. | c. | oxygen is
present. | b. | a physical change has just
occurred. | d. | organic
chemicals are present. | | | | |
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2.
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A
substance that undergoes a change in a chemical reaction is a. | a
product. | c. | a
reactant. | b. | a chemical. | d. | an enzyme. | | | | |
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3.
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What
happens in a chemical reaction? a. | Atoms are destroyed. | c. | Atoms are heated and cooled. | b. | Atoms are
created. | d. | Atoms are
rearranged. | | | | |
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4.
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In an
exothermic reaction, energy is transferred from a. | the reactants to the
surroundings. | c. | one reactant to
another. | b. | the surroundings to the
reactants. | d. | the container to
the chemicals. | | | | |
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5.
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Which
statement about endothermic reactions is correct? a. | Energy is always created in the form of
heat. | b. | Energy is transferred from the surroundings to the
reactants. | c. | Energy is used to force electrons to move to higher energy
levels. | d. | Energy is transferred from the reactants to the
surroundings. | | |
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6.
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Chemical energy is energy that is a. | added to a reaction in the form of
heat. | b. | present within atoms and molecules. | c. | caused by the
movement of electricity. | d. | released only when oxygen is present. | | |
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7.
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The
energy source in photosynthesis is a. | light energy. | c. | heat energy. | b. | chemical
energy. | d. | kinetic
energy. | | | | |
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8.
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Most
of the energy in an isooctane reaction is released in the form of a. | heat and
light. | c. | water. | b. | electrical energy. | d. | sound. | | | | |
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9.
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A
synthesis reaction is a reaction between at least two compounds in which a. | one breaks down
into at least two products. | b. | a compound is decomposed by an electric
current. | c. | a compound burns in the presence of
oxygen. | d. | a new, more complex compound is
formed. | | |
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10.
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What
kind of reaction occurs when potassium is placed in water? a. | a
single-displacement reaction | c. | a decomposition
reaction | b. | a double-displacement reaction | d. | electrolysis | | | | |
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11.
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Which
of the following is an example of a decomposition reaction? a. | photosynthesis | b. | digestion | c. | respiration | d. | exchange of ions between two
compounds | | |
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12.
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The
product of the synthesis reaction between sodium and chlorine gas is a. | polyethylene. | c. | sodium
chloride. | b. | carbon dioxide. | d. | copper (II) chloride. | | | | |
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13.
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When
methane reacts with abundant amounts of oxygen, the products are a. | carbon dioxide
and water. | c. | soot and
water. | b. | carbon monoxide and water. | d. | simple sugar and oxygen. | | | | |
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14.
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When
water is broken down by electrolysis, the products are a. | water and carbon
dioxide. | c. | hydrogen gas and
oxygen gas. | b. | hydrogen and oxygen ions. | d. | oxygen and methane. | | | | |
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15.
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Fragments of molecules that have at least one electron available for bonding are
called a. | ions. | c. | protons. | b. | orbits. | d. | radicals. | | | | |
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16.
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In a
redox reaction, the substance that accepts electrons is said to be a. | reduced. | c. | electrified. | b. | oxidized. | d. | clarified. | | | | |
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17.
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When
iron reacts with oxygen to form rust, each iron atom a. | loses three
ions. | c. | gains three
ions. | b. | loses three electrons. | d. | gains three electrons. | | | | |
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18.
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A
chemical equation is balanced by changing or adding a. | chemical
symbols. | c. | coefficients. | b. | subscripts. | d. | reactants. | | | | |
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19.
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A
balanced chemical equation shows the proportions of reactants and products necessary
for a. | the reaction to
occur. | c. | energy use to be
minimized. | b. | mass to be conserved. | d. | electrolysis to occur. | | | | |
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20.
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In
the reaction 2H2O ® 2H2 + O2, if you start with 2 mol of water, how
many moles of hydrogen gas are produced? a. | 1 mol | c. | 3 mol | b. | 2
mol | d. | 4
mol | | | | |
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21.
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In
the reaction 2H2O2 ® 2H2O + O2, if you start with 4 mol of
H2O2, how many moles of O2 will you end up with? a. | 4
mol | c. | 2
mol | b. | 3
mol | d. | 1
mol | | | | |
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22.
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If
you start with 5 mol of O2 in the reaction 2Mg + O2 ® 2MgO, how many
moles of Mg will you need? a. | 4 mol | c. | 8 mol | b. | 5
mol | d. | 10
mol | | | | |
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23.
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In
the reaction H2S + 2O2 ® H2SO4, the law of definite proportions
predicts that for every mole of H2S you will need how many moles of
O2? a. | 1
mol | c. | 3
mol | b. | 2
mol | d. | 4
mol | | | | |
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24.
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In
the reaction 2Mg + O2 ® 2MgO, the law of definite proportions states that for every 2 moles
of Mg you will need how many moles of O2? a. | 1
mol | c. | 3
mol | b. | 2
mol | d. | 4
mol | | | | |
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25.
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In a
balanced chemical reaction, the total mass of the products always equals the a. | molar mass of
the reactants. | c. | total mass of
the reactants. | b. | atomic mass of the reactants. | d. | proportional masses of the reactants. | | | | |
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26.
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A
balanced chemical equation indicates both the number of particles of reactants and products and the
number of a. | orbits. | c. | nuclei. | b. | electrons. | d. | moles. | | | | |
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27.
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All
of the following factors may speed up a chemical reaction except a. | smaller surface
area. | c. | higher
temperature. | b. | higher pressure. | d. | presence of a catalyst. | | | | |
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28.
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Large, bulky molecules react more slowly than small ones because they have less
opportunity to a. | become
heated. | c. | collide with
other molecules. | b. | be mixed with catalysts. | d. | increase their surface area. | | | | |
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29.
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What
could you do to make yeast dough rise more slowly? a. | Add more yeast
to the mixture. | c. | Add mold spores
to the dough. | b. | Knead the dough more
vigorously. | d. | Reduce the
temperature. | | | | |
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30.
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An
enzyme is a special kind of catalyst that works to a. | speed up a
specific biochemical reaction. | b. | break down chemical elements. | c. | provide a
special place where reactants can collect and interact. | d. | maintain the
correct temperature for a reaction. | | |
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31.
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Which
enzyme breaks down cellulose into smaller molecules? a. | amylase | c. | protease | b. | cellulase | d. | lipase | | | | |
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32.
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When
a chemical reaction and its reverse are occurring at the same time and at the same rate, the reaction
has achieved a. | displacement. | c. | imbalance. | b. | equilibrium. | d. | decomposition. | | | | |
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33.
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What
is the relationship between chemical equilibrium and the rates of forward and reverse
reaction? a. | In equilibrium,
the forward reaction rate must be greater than the reverse reaction rate. | b. | In equilibrium,
the forward reaction rate must be less than the reverse reaction rate. | c. | In equilibrium,
the forward and reverse reaction rates must be equal. | d. | In equilibrium,
both forward and reverse reactions must stop. | | |
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34.
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Le
Chatelier's principle states that increasing temperature favors a reaction that a. | releases energy
as heat. | c. | involves a
chemical catalyst. | b. | requires energy as heat. | d. | involves an enzyme. | | | | |
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35.
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Increasing the concentration of one substance in an equilibrium reaction favors the
reaction that a. | absorbs energy
as heat. | c. | produces less of
that substance. | b. | releases energy as heat. | d. | produces more of that substance. | | | | |
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Completion
Complete each sentence or
statement.
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36.
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A
chemical reaction that transfers energy from the reactants to the surroundings is referred to as
____________________.
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37.
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A(n)
____________________ reaction is one in which heat is transferred from the surroundings to the
reactants.
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38.
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The
general formula for a synthesis reaction is ____________________.
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39.
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In
a(n) ____________________ reaction, the reactants are broken down into other
substances.
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40.
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In a
combustion reaction, ____________________ is used to make reactants burn.
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41.
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When
methane burns in the presence of insufficient oxygen, the products of the reaction are water and
____________________.
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42.
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Alkali metals react violently with water to form metal ions, hydroxide ions, and
____________________.
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43.
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Balance the following chemical equation by filling in the correct coefficient on the
right-hand side. H2 + Cl2 ® ____________________ HCl
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44.
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Balance the following chemical equation by filling in the correct
coefficients.
____________________KI + Br2 ®
____________________KBr + I2
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45.
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Suppose you were producing zinc chloride by the reaction Zn + 2HCl ®
ZnCl2 + H2. If you started with 4 moles of zinc, you would need
____________________ moles of hydrogen chloride and you would produce ____________________ moles of
zinc chloride.
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