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. b. a physical change has just occurred.
c. oxygen is present. 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. b. a chemical. c. a reactant. d. an
enzyme.
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3.
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What
happens in a chemical reaction?
a. Atoms are destroyed. b. Atoms
are created. c. Atoms are heated and cooled. 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. b. the surroundings to the reactants.
c. one reactant to another. 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. b. chemical
energy. c. heat 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. b. electrical energy. c. water.
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 b. a double-displacement reaction c. a
decomposition 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. b. carbon dioxide. c. sodium
chloride. 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. b. carbon monoxide and water. c. soot 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. b. hydrogen and oxygen ions. c. hydrogen gas
and oxygen gas. 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. b. orbits.
c. protons. 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. b. oxidized.
c. electrified. 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. b. loses three electrons. c. gains three
ions. 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. b. subscripts. c. coefficients.
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. b. mass to be conserved.
c. energy use to be minimized. 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 b. 2 mol c. 3 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 b. 3 mol c. 2
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 b. 5 mol c. 8
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 b. 2 mol c. 3
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 b. 2 mol c. 3 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. b. atomic mass of the
reactants. c. total 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. b. electrons.
c. nuclei. 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. b. higher pressure. c. higher
temperature. 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. b. be mixed with
catalysts. c. collide with other molecules. 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. b. Knead the dough more vigorously. c. Add
mold spores to the dough. 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 b. cellulase c. protease
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. b. equilibrium.
c. imbalance. 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. b. requires energy as
heat. c. involves a chemical catalyst. 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. b. releases energy as
heat. c. produces less of that substance. d. produces more of that
substance.
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