CHEM 104 Exam 2 (Latest
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• Which of the following molecules possess a dipole moment? Choose all that apply.
C2H2
H2O
NF3 -✓✓H2O
NF3
• Using the trends in electronegativity on the periodic table, which of the following
elements should possess the lowest electronegativity value? -✓✓Barium
• Which of the following correctly describes a fundamental difference between single,
double and triple covalent bonds? -✓✓Double and triple bonds involve the sharing of 4
and 6 electrons between two atoms respectively while a single bond involves the
sharing of only 2 electrons between two atoms.
• Which of the following molecules contains only bonds that have no dipole moments? -
✓✓All of the above: Electronegativity differences between the atoms involved in the
bonds present are all less than 0.5. Check the electronegativity difference between a C
and H, a H and S, a N and Cl!
• When an oxygen atom combines with another oxygen atom, the bond formed is
correctly described by which of the following statements? Choose all that apply. -✓✓The
bond formed shows shared electrons spending equal amounts of time around both
atoms involved in the bond.
The bond formed is nonpolar.
• The premise behind VSEPR is most accurately stated by which of the following? -
✓✓The arrangement of atoms in a 3-D space will minimize the repulsion among valence
electron pairs.
• The statements are the distinguishing features of the representations referred to.
Carbon monoxide, CO, is a colorless, odorless but toxic gas. Which of the following best
describes the bonding present in this molecule? -✓✓Polar covalent bonding, with the
oxygen end partial negative and the carbon end partial positive.
Why: The electronegativity difference between C and O is 1.0 which is polar covalent
bonding and the oxygen has the higher electronegativity and so would be the partial
negative end of the bond.
, • How many total electrons (not electron pairs) are being shared in a double covalent
bond? -✓✓4
• In this section we have looked at various representations of molecular compounds.
Choose the correct statement from those below. -✓✓All of these statements are correct.
• If a central atom has a total of three electron sets and only one of those electron sets
is a lone pair and the others are bonding sets, the observed shape (3-D shape) would
be which of the following? -✓✓Bent
• Which of the following best describes the shape called a trigonal pyramidal shape? -
✓✓Three atoms connected to a central atom in a 3-D tripod-like shape with
approximately 107.5° bond angles.
• Which of the following statements about covalent bonding is incorrect? -✓✓Covalent
bonds can form between two metals.
• Which of the following substances has covalent bonds present? -✓✓NaNO2
Why: All of the above are ionic compounds and NaNO2 is the only one containing a
polyatomic ion whose atoms are held together by covalent bonds.
• The total number of valence electrons and the central atom is identified for each of the
following to begin the determination of a Lewis structure. Which contains an incorrect
identification of the total number of valence electrons, the central atom or is incorrect in
both the total number of valence electrons and the central atom identification? -
✓✓NO31-: 22 valence electrons and nitrogen is the central atom
Why: There are 24 valence electrons in the nitrate ion: 5 from the nitrogen, 6 from each
oxygen and the charge adds one more. Nitrogen is the central atom because it is less
electronegative or farther from fluorine.
• What factors impact the polarity of a molecule? -✓✓Both a & b impact molecular
polarity.
• Which of the following correctly describes the Lewis structure for acetylene gas
(C2H2), a gas that burns at a high temperature and is used in welding torches? -✓✓The
carbon atoms share three pairs of electrons with each other and each carbon then
shares a pair of electrons with a hydrogen atom.
• Consider a bond formed between hydrogen and oxygen. Which of the following
statements is incorrect? -✓✓The hydrogen tends to exert a stronger attraction for the
bonding electrons than oxygen does
Update) | Comprehensive Questions and
Answers | 100% Correct | Premium
• Which of the following molecules possess a dipole moment? Choose all that apply.
C2H2
H2O
NF3 -✓✓H2O
NF3
• Using the trends in electronegativity on the periodic table, which of the following
elements should possess the lowest electronegativity value? -✓✓Barium
• Which of the following correctly describes a fundamental difference between single,
double and triple covalent bonds? -✓✓Double and triple bonds involve the sharing of 4
and 6 electrons between two atoms respectively while a single bond involves the
sharing of only 2 electrons between two atoms.
• Which of the following molecules contains only bonds that have no dipole moments? -
✓✓All of the above: Electronegativity differences between the atoms involved in the
bonds present are all less than 0.5. Check the electronegativity difference between a C
and H, a H and S, a N and Cl!
• When an oxygen atom combines with another oxygen atom, the bond formed is
correctly described by which of the following statements? Choose all that apply. -✓✓The
bond formed shows shared electrons spending equal amounts of time around both
atoms involved in the bond.
The bond formed is nonpolar.
• The premise behind VSEPR is most accurately stated by which of the following? -
✓✓The arrangement of atoms in a 3-D space will minimize the repulsion among valence
electron pairs.
• The statements are the distinguishing features of the representations referred to.
Carbon monoxide, CO, is a colorless, odorless but toxic gas. Which of the following best
describes the bonding present in this molecule? -✓✓Polar covalent bonding, with the
oxygen end partial negative and the carbon end partial positive.
Why: The electronegativity difference between C and O is 1.0 which is polar covalent
bonding and the oxygen has the higher electronegativity and so would be the partial
negative end of the bond.
, • How many total electrons (not electron pairs) are being shared in a double covalent
bond? -✓✓4
• In this section we have looked at various representations of molecular compounds.
Choose the correct statement from those below. -✓✓All of these statements are correct.
• If a central atom has a total of three electron sets and only one of those electron sets
is a lone pair and the others are bonding sets, the observed shape (3-D shape) would
be which of the following? -✓✓Bent
• Which of the following best describes the shape called a trigonal pyramidal shape? -
✓✓Three atoms connected to a central atom in a 3-D tripod-like shape with
approximately 107.5° bond angles.
• Which of the following statements about covalent bonding is incorrect? -✓✓Covalent
bonds can form between two metals.
• Which of the following substances has covalent bonds present? -✓✓NaNO2
Why: All of the above are ionic compounds and NaNO2 is the only one containing a
polyatomic ion whose atoms are held together by covalent bonds.
• The total number of valence electrons and the central atom is identified for each of the
following to begin the determination of a Lewis structure. Which contains an incorrect
identification of the total number of valence electrons, the central atom or is incorrect in
both the total number of valence electrons and the central atom identification? -
✓✓NO31-: 22 valence electrons and nitrogen is the central atom
Why: There are 24 valence electrons in the nitrate ion: 5 from the nitrogen, 6 from each
oxygen and the charge adds one more. Nitrogen is the central atom because it is less
electronegative or farther from fluorine.
• What factors impact the polarity of a molecule? -✓✓Both a & b impact molecular
polarity.
• Which of the following correctly describes the Lewis structure for acetylene gas
(C2H2), a gas that burns at a high temperature and is used in welding torches? -✓✓The
carbon atoms share three pairs of electrons with each other and each carbon then
shares a pair of electrons with a hydrogen atom.
• Consider a bond formed between hydrogen and oxygen. Which of the following
statements is incorrect? -✓✓The hydrogen tends to exert a stronger attraction for the
bonding electrons than oxygen does
