Chapter 2 - Homework Answers
Chapter 2 Homework
Answers
Which choice contains a
statement about the nuclear atom that is FALSE?
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1.
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Protons and electrons have similar masses but different
charges
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2.
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Protons and
neutrons have similar masses but different charges
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3.
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Protons and neutrons
occupy a very small portion of the volume of atoms
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4.
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Protons and
neutrons make up nearly all the mass of the atom in which they are present
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5.
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Electrons occupy a
greater portion of the volume of atoms that any other subatomic particle
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How many electrons
are in an atom of 77Se?
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a.
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77
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b.
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76
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c.
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33
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d.
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34
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e.
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16
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The
hypothetical metal Q with atomic mass of 68.33 has two isotopes, 67Q (isotopic mass
66.945 amu) and 69Q (isotopic mass 68.958 amu). Calculate the
abundance of 67Q in %.
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a.
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31.2%
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b.
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68.8%
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c.
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25.0%
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d.
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77.8%
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e.
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22.2%
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An organic
compound has the molecular formula, C6H12O4. Which of these
could be its empirical formula?
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a.
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C6H12O4
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b.
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C3H6O2
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c.
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CH2O
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d.
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C3H4O2
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e.
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C2H3O
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How many
oxygen atoms are present in 11 formulas of the compound, molybdenum(II)
phosphate, Mo3(PO4)2? 88
Match the element below's name and group number with its Z value. Enter only the letter of the
correct choice.
a. Z = 32
b. Z = 16
c. Z = 2
d. Z = 3
e. Z = 42
molybdenum; 6B (6) e
a. Z = 32
b. Z = 16
c. Z = 2
d. Z = 3
e. Z = 42
molybdenum; 6B (6) e
In the box below, write the molecular formula of the compound
represented by the line drawing below. Your answer should be submitted as CxHy
where x and y are whole numbers of carbon and hydrogen atoms in the molecule. C6H14
The correct molecular formula of dinitrogen pentoxide is:
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1.
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(NO5)2
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2.
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N2O5
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3.
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2NO5
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4.
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N2P5O
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The
chemical symbol for nitrite is NO21-.
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1.
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True
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2.
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False
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The mass number of an element refers to sum of the number of
protons and the number of what other particle in its atoms? neutron
How many
neutrons are there in the nucleus of 108Ag?
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a.
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54
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b.
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108
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c.
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47
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d.
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61
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e.
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18
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Cations are particles with fewer electrons than protons.
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1.
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True
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2.
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False
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The
hypothetical metal Q has two isotopes, 50Q (isotopic mass 49.9715 amu, abundance 89.65%), 52Q (isotopic mass
51.9663 amu). Calculate the atomic mass of Q. 50.18
A sugar has
the molecular formula, C6H12O6. Which of these
could be its empirical formula?
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a.
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C6H12O6
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b.
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C3H6O3
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c.
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CH2O
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d.
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C2H4O2
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e.
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CH3O
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How many
total atoms are present in 7 formulas of the compound, molybdenum(III)
phosphate, MoPO4? 42
Which of these best describes the set of elements below?
titanium, scandium, iron
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a.
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main group metal,
noble gas, transition metal
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b.
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transition metal,
alkali metal, alkaline earth metal
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c.
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non-metal,
metalloid, main group metal
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d.
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halogen, alkali
metal, transition metal
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e.
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all transition metals
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What is the sum of the number of carbon atoms and hydrogen atoms
present in the molecule represented by the line drawing below? Enter the whole
number in the box below. 20
What is the formula of dihydrogen heptasulfide? Enter your answer
with atomic symbols and numbers, such as A2B3, without any spaces. H2S7
What is the name of the following binary compound?
Al2O3
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a.
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aluminum oxide
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b.
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dialuminum trioxide
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c.
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aluminum (III)
trioxide
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d.
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bisaluminum trioxide
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e.
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dialuminum
trioxygen
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The number
of neutrons in an atom of 203Hg is 123
____________________ are atoms with nuclei having the same number
of protons but different numbers of neutrons. (answer with all lower case
letters) isotopes or nuclides
The hypothetical
metal Q has two isotopes, 50Q (isotopic mass 49.9715 amu, abundance 51.99%), 52Q (isotopic mass
51.9663 amu). Calculate the atomic mass of Q. 50.93
The
__________ _________ provides the ratio of atoms in a compound. (answer with
all lower case letters) empirical formula
How many total atoms
are present in 8 formulas of the compound, molybdenum(III) phosphate, MoPO4? 48
Which
of these best describes the set of elements below?
iron, oxygen, boron
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a.
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transition metal, non-metal, metalloid
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b.
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main group metal,
transiton metal, non-metal
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c.
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metalloid, halogen,
noble gas
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d.
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non-metal,
metalloid, halogen
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e.
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alkali metal,
non-metal, transition metal
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How
any hydrogen atoms are present in the molecule represented by the line drawing
below? Enter the whole number in the box below. 10
The correct molecular formula
for strontium chloride is:
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1.
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SrCl
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2.
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StCl2
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3.
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SrCl2
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4.
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SrClO2
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Consider 235U. How many
protons are present in this isotope?
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1.
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235
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2.
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none of these
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3.
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143
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4.
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92
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5.
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177
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How many
neutrons are there in the nucleus of a 232Th atom?
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a.
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232
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b.
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90
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c.
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81
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d.
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151
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e.
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142
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An atom containing 34 protons, 43 neutrons, and 34 electrons would
have the symbol:
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a.
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77 Se
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b.
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77 Ir
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c.
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77 Tc
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d.
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43 Se
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e.
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43 Tc
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Naturally occurring bromine consists of two isotopes: and . The atomic mass for bromine
is approximately 80. What are reasonable estimates of the relative percentages
of and respectively?
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a.
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10, 90
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b.
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25, 75
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c.
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50, 50
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d.
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75, 25
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e.
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90, 10
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The empirical formula for aluminum chloride is
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a.
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AlCl
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b.
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Al3Cl
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c.
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AlCl3
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d.
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Al2Cl3
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e.
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Al2Cl6
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How many
oxygen atoms are present in 8 formulas of the compound, molybdenum(III)
phosphate, MoPO4? 32
Match the element below's name and group number with its Z value. Enter only the letter of the
correct choice.
a. Z = 32
b. Z = 16
c. Z = 2
d. Z = 3
e. Z = 42
lithium; 1A (1) d
a. Z = 32
b. Z = 16
c. Z = 2
d. Z = 3
e. Z = 42
lithium; 1A (1) d
What is the sum of the number of carbon atoms and hydrogen atoms
present in the molecule represented by the line drawing below? Enter the whole
number in the box below. 21
What is the name of the following binary compound?
CCl4
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a.
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carbon tetrachloride
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b.
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methylene chloride
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c.
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carbon chloride
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d.
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carbon (IV)
tetrachloride
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e.
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methane
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The correct molecular formula for ammonium chloride is:
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1.
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AmCl
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2.
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NH3Cl
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3.
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NH4Cl
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4.
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AmCl2
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The atomic number of an element refers to the number of what
subatomic particle in its atoms?
proton
An iron-56 nucleus contains
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a.
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56 protons and 26
neutrons
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b.
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30 protons and 26
neutrons
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c.
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26 protons and 26
neutrons
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d.
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26 protons, 30
neutrons and 26 electrons
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e.
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26 protons and 30 neutrons
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Atomic and Isotopic Weights
Boron has two principal
naturally occurring isotopes, 10B (isotopic mass 10.013 amu) and 11B (isotopic mass
11.009 amu). If a random sample of this element collected from the tail of a
comet has an weighted average atomic mass of 10.801 amu, what is the percent abundance
of the lower-mass isotope?
(Example answer: 12.3) 20.88
How many
oxygen atoms are present in 15 formulas of the compound, molybdenum(IV)
phosphate, Mo3(PO4)4? Enter only the number please. 240
Which of the following elements are lanthanides?
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1.
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Sm and Er
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2.
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Uranium and Np
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3.
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Ti and Cr
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4.
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Kr and xenon
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What is the formula of triphosphorus tetranitride? Enter your
answer with atomic symbols and numbers, such as A2B3, without any spaces. P3N4
The correct molecular formula for ammonium chloride is:
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1.
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NH4Cl
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2.
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NH3Cl
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3.
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AmCl
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4.
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AmCl2
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Consider 203Hg. How many
neutrons are present in this nuclide?
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1.
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283
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2.
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None of these is
correct
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3.
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80
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4.
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123
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5.
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203
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6.
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83
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How many
neutrons are there in the nucleus of 108Ag?
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a.
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54
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b.
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108
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c.
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47
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d.
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61
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e.
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18
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Which of these ions contains 33 protons, 39 neutrons, and 34
electrons?
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1.
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none of these
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2.
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67Y1+
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3.
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73Se1+
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4.
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72As1+
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5.
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73As1-
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What is the
empirical formula and empirical formula mass for the following compound?
C3H6O3
C3H6O3
|
a.
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C3H6O3 ,
90 g/mol
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b.
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C2H4O2 ,
60 g/mol
|
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c.
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CH2O, 30 g/mol
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d.
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CH3O, 31 g/mol
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e.
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None of these
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What is the name of the following binary compound?
CCl4
|
a.
|
carbon tetrachloride
|
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b.
|
methylene chloride
|
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c.
|
carbon chloride
|
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d.
|
carbon (IV)
tetrachloride
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e.
|
methane
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The
systematic (IUPAC) name of Sr(NO2)2 is:
|
1.
|
strontium(II)
nitrite
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2.
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strontium dinitrite
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3.
|
strontium nitrate
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4.
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strontium nitrite
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A type of subatomic particle that occupies the region outside the
nucleus of atoms is electron
In which of the following pairs of isotopes is the number of protons the same?
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a.
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3H and 3He
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b.
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14C and 14N
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c.
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19F and 18F
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d.
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40Ar and 41K
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e.
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60Co and 60Ni
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The symbol for the transition metal with 117 neutrons is most
likely:
|
a.
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109Ag
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b.
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37Cl
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c.
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65Cu
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d.
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195Pt
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e.
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184W
|
Suppose
that the radioactive element Technetium (Tc, Z = 43) has three isotopes: 97Tc (21.72%,
96.98 amu), 98Tc (58.70%, 97.96 amu and 99Tc (98.93 amu).
What is the atomic mass of Tc as it would appear in the periodic table? Do not
enter units with your answer and use the correct number of significant figures.
97.94
A sugar has
the molecular formula, C6H12O6. Which of these
could be its empirical formula?
|
a.
|
C6H12O6
|
|
b.
|
C3H6O3
|
|
c.
|
CH2O
|
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d.
|
C2H4O2
|
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e.
|
CH3O
|
What is the formula of triarsenic heptasulfide? Enter your answer
with atomic symbols and numbers, such as A2B3, without any spaces. As3S7
Chlorine
has two naturally occurring isotopes, 35Cl and 37Cl. How many protons, neutrons, and electrons are
present in 35Cl?
|
a.
|
|
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b.
|
|
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c.
|
|
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d.
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|
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e.
|
|
What is the
identity of element Q if the ion Q2+ contains 10 electrons?
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a.
|
|
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b.
|
|
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c.
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|
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d.
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|
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e.
|
|
The
hypothetical metal Q with atomic mass of 68.33 has two isotopes, 67Q (isotopic mass
66.945 amu) and 69Q (isotopic mass 68.958 amu). Calculate the
abundance of 67Q in %.
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a.
|
|
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b.
|
|
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c.
|
|
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d.
|
|
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e.
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Which
of the following is the empirical formula for hexane, C6H14?
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a.
|
|
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b.
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|
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c.
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|
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d.
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|
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e.
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Uranium, plutonium, and neptunium are classified as:
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1.
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2.
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3.
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4.
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What is the name of the following binary compound?
N2O
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a.
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b.
|
|
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c.
|
|
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d.
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|
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e.
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The correct molecular formula for potassium nitrate is:
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1.
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2.
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3.
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4.
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