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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According to the law of conservation of mass, when sodium, hydrogen, and oxygen react
to form a compound, the mass of the compound is ____ the sum of the masses of the individual
elements. a. | equal
to | c. | less
than | b. | greater
than | d. | either greater
than or less than | | | | |
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2.
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According to Dalton's atomic theory, atoms a. | are destroyed in
chemical reactions. | b. | can be divided. | c. | of each element
are identical in size, mass, and other properties. | d. | of different
elements cannot combine. | | |
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3.
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The
law of definite proportions a. | contradicted Dalton's atomic theory. | b. | was explained by
Dalton's atomic theory. | c. | replaced the law of conservation of
mass. | d. | assumes that atoms of all elements are
identical. | | |
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4.
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Dalton's atomic theory helped to explain the law of conservation of mass because it
stated that atoms a. | could not
combine. | c. | all had the same
mass. | b. | could not be created or
destroyed. | d. | were
invisible. | | | | |
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5.
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When
an electrical current passed through a glass tube, a paddle wheel placed between the electrodes
moved. Scientists concluded that a. | a magnetic field was produced. | b. | particles were
passing from the cathode to the anode. | c. | there was gas in the tube. | d. | atoms were
indivisible. | | |
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6.
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Experiments with cathode rays led to the discovery of the a. | proton. | c. | neutron. | b. | nucleus. | d. | electron. | | | | |
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7.
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Who
discovered the nucleus by bombarding gold foil with positively charged particles and noting that some
particles were widely deflected? a. | Rutherford | c. | Chadwick | b. | Dalton | d. | Bohr | | | | |
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8.
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Because most particles fired at metal foil passed straight through, Rutherford
concluded that a. | atoms were
mostly empty space. | c. | electrons formed
the nucleus. | b. | atoms contained no charged
particles. | d. | atoms were
indivisible. | | | | |
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9.
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Rutherford fired positively charged particles at metal foil and concluded that most of
the mass of an atom was a. | in the electrons. | c. | evenly spread throughout the atom. | b. | concentrated in
the nucleus. | d. | in rings around
the atom. | | | | |
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10.
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What
did Rutherford conclude about the structure of the atom? a. | An atom is
indivisible. | b. | Electrons make up the center of an
atom. | c. | An atom carries a positive charge. | d. | An atom contains
a small, dense, positively charged central region. | | |
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11.
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Which
part of an atom has a mass approximately equal to 1/2000 of the mass of a common hydrogen
atom? a. | nucleus | c. | proton | b. | electron | d. | electron cloud | | | | |
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12.
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Protons within a nucleus are attracted to each other by a. | nuclear
forces. | c. | their energy
levels. | b. | opposite charges. | d. | electron repulsion. | | | | |
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13.
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The
charge on the electron cloud a. | prevents compounds from forming. | b. | balances the
charge on the nucleus. | c. | attracts electron clouds in other atoms to form
compounds. | d. | does not exist. | | |
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14.
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The
forces that hold the particles in the nucleus together are called a. | nuclear
forces. | c. | magnetic
forces. | b. | gravitational forces. | d. | electron clouds. | | | | |
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15.
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How
many isotopes of hydrogen are known?
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16.
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The
relative atomic mass of an atom can be found by comparing the mass of the atom to the mass
of a. | one atom of
carbon-12. | c. | a
proton. | b. | one atom of hydrogen-1. | d. | uranium-235. | | | | |
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17.
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What
is the atomic number for aluminum from the figure above?
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18.
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An
atom of potassium has 19 protons and 20 neutrons. What is its mass number?
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19.
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Ag-109 has 62 neutrons. The neutral atom has a. | 40
electrons. | c. | 53
electrons. | b. | 47 electrons. | d. | 62 electrons. | | | | |
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20.
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Molar
mass a. | is the mass in
grams of one mole of a substance. | b. | is numerically equal to the average atomic mass of the
element. | c. | both a and b | d. | neither a nor
b | | |
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Problem
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21.
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How
many atoms are present in 8.00 mol of chlorine atoms?
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22.
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How
many atoms are present in 80.0 mol of zirconium?
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23.
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How
many moles of platinum are equivalent to 1.20 ´ 1024 atoms?
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24.
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How
many moles of iron are equivalent to 1.11 ´ 1025 atoms?
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25.
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Determine the mass in grams of 5.00 mol of oxygen. The molar mass of oxygen is 16.00
g/mol.
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26.
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Determine the mass in grams of 10.0 mol of bromine. The molar mass of bromine is 79.90
g/mol.
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27.
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Determine the number of moles of helium in 10.0 g of helium. The molar mass of helium
is 4.00 g/mol.
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28.
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Determine the number of moles in 100. g of potassium. The molar mass of potassium is
39.10 g/mol.
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29.
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The
mass of 1 mol of gold atoms is 196.97 g. Find the mass of 1 atom of gold.
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30.
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Calculate the mass in grams of 9.00 mol of potassium (molar mass 39.10
g/mol).
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31.
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Calculate the number of atoms in 10.0 g of sulfur (molar mass 32.07
g/mol).
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Essay
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32.
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Explain what is meant by the law of definite proportions, the law of conservation of
mass, and the law of multiple proportions.
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33.
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Why
do scientists use Dalton's theory, even though parts of it have been proven wrong? How much of
Dalton's theory do scientists still accept?
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34.
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What
can you determine about the atomic structure of an element and one of its isotopes if you know the
atomic number and mass numbers?
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35.
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Explain the significance of Avogadro's constant, 6.022 ´ 1023. What is the relationship between it and the molar mass of oxygen,
16.00 g/mol?
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