Question 1

Which of the following is the shortest bond? The number in parentheses is the bond energy.

Accepted Answer

A) C-C (348 kJ/mol) 
B) C-F (453 kJ/mol) 
C) C-H (411 kJ/mol) 
D) C-Cl (339 kJ/mol) 
E) C-O (358 kJ/mol) 
A) C-C (348 kJ/mol) 
B) C-F (453 kJ/mol) 
C) C-H (411 kJ/mol) 
D) C-Cl (339 kJ/mol) 
E) C-O (358 kJ/mol) B

Question 2

Which statement A-D about chemical bonds is not correct?

Accepted Answer

A) The attraction of the negatively charged electrons to the positively charged nuclei causes the electrostatic potential energy to decrease as two atoms come together. 
B) The repulsion of the negatively charged electrons with each other and the positively charged nuclei with each other causes the electrostatic potential energy to increase when the two atoms are very close together. 
C) As two atoms come together, the electrostatic potential energy goes through a minimum.The distance between the atoms at which this minimum occurs is called the bond length. 
D) The bond energy is the energy released when two atoms infinitely far apart come together at a distance that minimizes the electrostatic potential energy. 
E) Statements A-D are all correct. 
A) The attraction of the negatively charged electrons to the positively charged nuclei causes the electrostatic potential energy to decrease as two atoms come together. 
B) The repulsion of the negatively charged electrons with each other and the positively charged nuclei with each other causes the electrostatic potential energy to increase when the two atoms are very close together. 
C) As two atoms come together, the electrostatic potential energy goes through a minimum.The distance between the atoms at which this minimum occurs is called the bond length. 
D) The bond energy is the energy released when two atoms infinitely far apart come together at a distance that minimizes the electrostatic potential energy. 
E) Statements A-D are all correct. E

Question 3

The following Lewis symbol corresponds to which ion?

Accepted Answer

A) FF1F1F1S1F1F1F10 
B) OF1F1F1S1F1F1F10 
C) C2F1F1F1S1F1F1F10 
D) B3F1F1F1S1F1F1F10 
E) N2F1F1F1S1F1F1F10 
A) FF1F1F1S1F1F1F10 
B) OF1F1F1S1F1F1F10 
C) C2F1F1F1S1F1F1F10 
D) B3F1F1F1S1F1F1F10 
E) N2F1F1F1S1F1F1F10 C

Question 4

Which of these statements correctly describes why methane and carbon dioxide are considered to be significant greenhouse gases?
I. Both have permanent dipole moments that change with vibration of the molecule.
II. Neither has a permanent dipole moment, but a dipole moment is produced when the
Molecule vibrates.
III. The concentration of carbon dioxide in the atmosphere increases when fossil fuels are
Mined and burned.

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and III only 
E) II and III only 
A) I only 
B) II only 
C) III only 
D) I and III only 
E) II and III only

Question 5

What is the formal charge of each atom (from left to right), neglecting the hydrogens, in the following resonance structure of CHF1F1F1S1F1F1F102N2?

Accepted Answer

A) 0, 0, 0 
B) (F1F1F1S1F1F1F101, F1F1F1S1F1F1F101, 0) 
C) 0, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101 
D) 0, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101 
E) (F1F1F1S1F1F1F101, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101) 
A) 0, 0, 0 
B) (F1F1F1S1F1F1F101, F1F1F1S1F1F1F101, 0) 
C) 0, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101 
D) 0, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101 
E) (F1F1F1S1F1F1F101, F1F1F1S1F1F1F101, F1F1F1S1F1F1F101)

Question 6

O-S-S-O has three resonance Lewis structures that complete the octet for all the atoms. Which statements about these structures are correct?
I. All are equivalent.
II. All are nonequivalent.
III. Two are equivalent, and one is nonequivalent.
IV. The formal charges on all the atoms are zero in at least one structure.
V. All the bonds have double-bond character.

Accepted Answer

A) III and V 
B) I and IV 
C) II and IV 
D) I and V 
E) III, IV, and V 
A) III and V 
B) I and IV 
C) II and IV 
D) I and V 
E) III, IV, and V

Question 7

Which of the following represents the best Lewis structure for dinitrogen sulfide?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 8

Which one of the following molecules violates the octet rule?

Accepted Answer

A) O3 
B) N2O 
C) PBr3 
D) BeF2 
E) AsF3 
A) O3 
B) N2O 
C) PBr3 
D) BeF2 
E) AsF3

Question 9

The formal charge of an atom in a Lewis structure is defined as ________

Accepted Answer

A) the difference between the number of bonding electrons and nonbonding electrons assigned to an atom. 
B) the difference between the number of valence electrons in a free atom and the total number of valence electrons in the molecule. 
C) the difference between the number of valence electrons in a free atom and the number of electrons assigned to it in a Lewis structure. 
D) the difference between the number of valence electrons in a free atom and the number of bonding electrons assigned to it. 
E) the difference between the number of valence electrons in a free atom and the number of nonbonding electrons assigned to it. 
A) the difference between the number of bonding electrons and nonbonding electrons assigned to an atom. 
B) the difference between the number of valence electrons in a free atom and the total number of valence electrons in the molecule. 
C) the difference between the number of valence electrons in a free atom and the number of electrons assigned to it in a Lewis structure. 
D) the difference between the number of valence electrons in a free atom and the number of bonding electrons assigned to it. 
E) the difference between the number of valence electrons in a free atom and the number of nonbonding electrons assigned to it.

Question 10

Assign the formal charges to each atom in the resonance structure of ozone (O3) shown below.

Accepted Answer

@#IMG-DLM& The formal charges

Question 11

Indicate which of the following molecules has only a single bond.

Accepted Answer

A) O2 
B) CO 
C) CNF1F1F1S1F1F1F10 
D) N2 
E) Cl2 
A) O2 
B) CO 
C) CNF1F1F1S1F1F1F10 
D) N2 
E) Cl2

Question 12

Which of these statements correctly describes the electronic charge distribution in a molecule?
I. The charge density around each atom is the same as it is in the free atom.
II. The electronic charge is distributed equally around each atom in the molecule.
III. Electrons are attracted preferentially to atoms with high electronegativity.
IV. Electronic charge density is enhanced in the space between atoms to form a bond.
V. Electrons are always shared between atoms and never transferred from one atom to another.

Accepted Answer

A) I only 
B) II and III only 
C) III and IV only 
D) II only 
E) V only 
A) I only 
B) II and III only 
C) III and IV only 
D) II only 
E) V only

Question 13

Which statement about the most stable Lewis structures of cyanamide (H2NCN) and its structural isomer (HNCNH) is not correct?

Accepted Answer

A) Both have 16 valence electrons. 
B) One has a triple bond. 
C) One has two double bonds. 
D) All atoms in both structures have formal charges of zero. 
E) Cyanamide has an equivalent resonance structure with two double bonds. 
A) Both have 16 valence electrons. 
B) One has a triple bond. 
C) One has two double bonds. 
D) All atoms in both structures have formal charges of zero. 
E) Cyanamide has an equivalent resonance structure with two double bonds.

Question 14

How many valence electrons are there in PO43F1F1F1S1F1F1F10?

Accepted Answer

A) 10 
B) 14 
C) 23 
D) 29 
E) 32 
A) 10 
B) 14 
C) 23 
D) 29 
E) 32

Question 15

To absorb infrared radiation, a molecule must have ________

Accepted Answer

A) a vibrational motion that causes a change in dipole moment. 
B) a double or triple bond. 
C) no center of symmetry, so one side is different from the other. 
D) atoms other than carbon and hydrogen. 
E) at least one carbon and one hydrogen atom. 
A) a vibrational motion that causes a change in dipole moment. 
B) a double or triple bond. 
C) no center of symmetry, so one side is different from the other. 
D) atoms other than carbon and hydrogen. 
E) at least one carbon and one hydrogen atom.

Question 16

Use the formal charge as a criterion to identify the Lewis structure below that is most stable.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 17

Indicate which molecule contains the largest number of nonbonding electrons.

Accepted Answer

A) H2 
B) CO 
C) N2 
D) NO 
E) O2 
A) H2 
B) CO 
C) N2 
D) NO 
E) O2

Question 18

Which of the following compounds would have the largest enthalpy of formation? The bond energies are given in parentheses.

Accepted Answer

A) HF1F1F1S1F1F1F10Br (366 kJ/mol) 
B) HF1F1F1S1F1F1F10I (299 kJ/mol) 
C) HF1F1F1S1F1F1F10Cl (431 kJ/mol) 
D) HF1F1F1S1F1F1F10F (567 kJ/mol) 
E) HF1F1F1S1F1F1F10H (436 kJ/mol) 
A) HF1F1F1S1F1F1F10Br (366 kJ/mol) 
B) HF1F1F1S1F1F1F10I (299 kJ/mol) 
C) HF1F1F1S1F1F1F10Cl (431 kJ/mol) 
D) HF1F1F1S1F1F1F10F (567 kJ/mol) 
E) HF1F1F1S1F1F1F10H (436 kJ/mol)

Question 19

Indicate the element with the largest electronegativity.

Accepted Answer

A) K 
B) Cs 
C) Mg 
D) B 
E) Li 
A) K 
B) Cs 
C) Mg 
D) B 
E) Li

Question 20

A covalent bond results when ________

Accepted Answer

A) electrons are transferred from one atom to another atom. 
B) atoms pool their electrons to form a "sea" of electrons. 
C) atoms have outer electrons with the same principal quantum number. 
D) electrons are shared between a pair of atoms. 
E) an atom has 8 valence electrons. 
A) electrons are transferred from one atom to another atom. 
B) atoms pool their electrons to form a "sea" of electrons. 
C) atoms have outer electrons with the same principal quantum number. 
D) electrons are shared between a pair of atoms. 
E) an atom has 8 valence electrons.

Which of the following is the shortest bond? The number in parentheses is the bond energy.

Which statement A-D about chemical bonds is not correct?

The following Lewis symbol corresponds to which ion?

What is the formal charge of each atom (from left to right), neglecting the hydrogens, in the following resonance structure of CH₂N₂?

Which of the following represents the best Lewis structure for dinitrogen sulfide?

Which one of the following molecules violates the octet rule?

The formal charge of an atom in a Lewis structure is defined as ________

Assign the formal charges to each atom in the resonance structure of ozone (O₃) shown below.

Indicate which of the following molecules has only a single bond.

Which statement about the most stable Lewis structures of cyanamide (H₂NCN) and its structural isomer (HNCNH) is not correct?

How many valence electrons are there in PO₄³^?

To absorb infrared radiation, a molecule must have ________

Use the formal charge as a criterion to identify the Lewis structure below that is most stable.

Indicate which molecule contains the largest number of nonbonding electrons.

Which of the following compounds would have the largest enthalpy of formation? The bond energies are given in parentheses.

Indicate the element with the largest electronegativity.

A covalent bond results when ________

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

Exam 8: Chemical Bonds: What Makes a Gas a Greenhouse Gas

Which of the following is the shortest bond? The number in parentheses is the bond energy.

Which statement A-D about chemical bonds is not correct?

The following Lewis symbol corresponds to which ion?

What is the formal charge of each atom (from left to right), neglecting the hydrogens, in the following resonance structure of CH2N2?

Which of the following represents the best Lewis structure for dinitrogen sulfide?

Which one of the following molecules violates the octet rule?

The formal charge of an atom in a Lewis structure is defined as ________

Assign the formal charges to each atom in the resonance structure of ozone (O3) shown below.

Indicate which of the following molecules has only a single bond.

Which statement about the most stable Lewis structures of cyanamide (H2NCN) and its structural isomer (HNCNH) is not correct?

How many valence electrons are there in PO43?

To absorb infrared radiation, a molecule must have ________

Use the formal charge as a criterion to identify the Lewis structure below that is most stable.

Indicate which molecule contains the largest number of nonbonding electrons.

Which of the following compounds would have the largest enthalpy of formation? The bond energies are given in parentheses.

Indicate the element with the largest electronegativity.

A covalent bond results when ________

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

What is the formal charge of each atom (from left to right), neglecting the hydrogens, in the following resonance structure of CH₂N₂?

Assign the formal charges to each atom in the resonance structure of ozone (O₃) shown below.

Which statement about the most stable Lewis structures of cyanamide (H₂NCN) and its structural isomer (HNCNH) is not correct?

How many valence electrons are there in PO₄³^?