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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What
SI unit is used to measure the number of representative particles in a substance? a. | kilogram | c. | kelvin | b. | ampere | d. | mole | | | | |
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2.
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How
many hydrogen atoms are in 5 molecules of isopropyl alcohol, C H O?
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3.
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Which
of the following elements exists as a diatomic molecule? a. | neon | c. | nitrogen | b. | lithium | d. | sulfur | | | | |
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4.
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Avogadro's number of representative particles is equal to one ____. a. | kilogram | c. | kelvin | b. | gram | d. | mole | | | | |
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5.
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All
of the following are equal to Avogadro's number EXCEPT ____. a. | the number of
atoms of bromine in 1 mol Br | b. | the number of atoms of gold in 1 mol
Au | c. | the number of
molecules of nitrogen in 1 mol N | d. | the number of molecules of carbon monoxide in 1 mol
CO | | |
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6.
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How
many moles of tungsten atoms are in 4.8  10 atoms of tungsten?
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7.
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How
many atoms are in 0.075 mol of titanium?
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8.
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How
many molecules are in 2.10 mol CO ?
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9.
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What
is true about the molar mass of chlorine gas? a. | The molar mass is 35.5 g. | b. | The molar mass
is 71.0 g. | c. | The molar mass is equal to the mass of one mole of chlorine
atoms. | d. | none of the above | | |
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10.
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The
mass of a mole of NaCl is the ____. a. | molar mass | c. | molecular mass | b. | atomic
mass | d. | gram atomic
mass | | | | |
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11.
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What
is the molar mass of AuCl3? a. | 96 g | c. | 232.5 g | b. | 130
g | d. | 303.6
g | | | | |
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12.
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What
is the molar mass of (NH ) CO ? a. | 144 g | c. | 96 g | b. | 138 g | d. | 78 g | | | | |
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13.
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What
is the mass in grams of 5.90 mol C H ? a. | 0.0512 g | c. | 389 g | b. | 19.4
g | d. | 673
g | | | | |
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14.
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What
is the number of moles in 432 g Ba(NO ) ? a. | 0.237 mol | c. | 1.65 mol | b. | 0.605
mol | d. | 3.66
mol | | | | |
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15.
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What
is the mass of silver in 3.4 g AgNO ? a. | 0.025 g | c. | 2.2 g | b. | 0.64
g | d. | 3.0
g | | | | |
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16.
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What
is the mass of oxygen in 250 g of sulfuric acid, H SO ? a. | 0.65 g | c. | 16 g | b. | 3.9 g | d. | 160 g | | | | |
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17.
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The
molar volume of a gas at STP occupies ____. a. | 22.4 L | c. | 1 kilopascal | b. | 0 C | d. | 12
grams | | | | |
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18.
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What
is the volume, in liters, of 0.500 mol of C H gas at
STP? a. | 0.0335
L | c. | 16.8
L | b. | 11.2
L | d. | 22.4
L | | | | |
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19.
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If
the density of an unknown gas Z is 4.50 g/L at STP, what is the molar mass of gas Z? a. | 0.201
g/mol | c. | 26.9
g/mol | b. | 5.00 g/mol | d. | 101 g/mol | | | | |
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20.
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To
determine the formula of a new substance, one of the first steps is to find the
____. a. | molar
mass | c. | volume at
STP | b. | percent
composition | d. | number of
particles per mole | | | | |
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21.
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What
is the percent composition of chromium in BaCrO ? a. | 4.87% | c. | 20.5% | b. | 9.47% | d. | 25.2% | | | | |
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22.
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What
is the percent composition of carbon, in heptane, C H ?
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23.
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Which
of the following compounds has the lowest percent gold content by weight? a. | AuOH | c. | AuCl | b. | Au(OH) | d. | AuI | | | | |
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24.
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The
lowest whole-number ratio of the elements in a compound is called the ____. a. | empirical
formula | c. | binary
formula | b. | molecular formula | d. | representative formula | | | | |
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25.
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Which
of the following is NOT an empirical formula?
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26.
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What
is the empirical formula of a substance that is 53.5% C, 15.5% H, and 31.1% N by
weight?
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Short Answer
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27.
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Calculate the molecular formulas of the compounds having the following empirical
formulas and molar masses: C H , 58
g/mol; CH, 78 g/mol; and HgCl, 236.1 g/mol.
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