Question 1

A nonpolar covalent bond (i.e., pure covalent)would form in which one of the following pairs of atoms?

Accepted Answer

A) Na - Cl 
B) H - Cl 
C) Li - Br 
D) Se - Br 
E) Br - Br 
A) Na - Cl 
B) H - Cl 
C) Li - Br 
D) Se - Br 
E) Br - Br

Question 2

Which one of the following is most likely to be an ionic compound?

Accepted Answer

A) NCl3 
B) BaCl2 
C) CO 
D) SO2 
E) SF4 
A) NCl3 
B) BaCl2 
C) CO 
D) SO2 
E) SF4

Question 3

Assuming the octet rule is obeyed, how many covalent bonds will a nitrogen atom form to give a formal charge of zero?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 4

Write a Lewis structure for the nitrate ion, NO3-, showing all non-zero formal charges.

Accepted Answer

Question 5

Which of the elements listed below has the greatest electronegativity?

Accepted Answer

A) Se 
B) Sb 
C) K 
D) Ga 
E) Fe 
A) Se 
B) Sb 
C) K 
D) Ga 
E) Fe

Question 6

What is the formal charge on the oxygen atom in N2O (the atomic order is N-N-O)?

Accepted Answer

A) 0 
B) +1 
C) -1 
D) -2 
E) +2 
A) 0 
B) +1 
C) -1 
D) -2 
E) +2

Question 7

Use the Born-Haber cycle to calculate the lattice energy of MgO (s)given the following data: $\Delta$H(sublimation)Mg = 130 kJ/mol
I1 (Mg)= 738.1 kJ/mol
I2 (Mg)= 1450 kJ/mol
Bond energy (O=O)= 498.7 kJ/mol
EA (O)= 141 kJ/mol
EA (O-)= -780 kJ/mol
$\Delta$H   (MgO(s))= -601.8 kJ/mol

Accepted Answer

A) 2200 kJ/mol 
B) 2800 kJ/mol 
C) 3200 kJ/mol 
D) 3800 kJ/mol 
E) 4100 kJ/mol 
A) 2200 kJ/mol 
B) 2800 kJ/mol 
C) 3200 kJ/mol 
D) 3800 kJ/mol 
E) 4100 kJ/mol

Question 8

Assuming the octet rule is obeyed, how many covalent bonds will a carbon atom form to give a formal charge of zero?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 9

Use the bond enthalpy data given to estimate the heat released when 6.50 g of nitrogen gas reacts with excess hydrogen gas to form ammonia at 25°C. BE(N$\equiv$N)= 941.4 kJ/mol
BE(H-H)= 436.4 kJ/mol
BE(N-H)= 393 kJ/mol

Accepted Answer

A) 228 kJ 
B) 340 kJ 
C) 107 kJ 
D) 46.1 kJ 
E) 24.9 kJ 
A) 228 kJ 
B) 340 kJ 
C) 107 kJ 
D) 46.1 kJ 
E) 24.9 kJ

Question 10

Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)?

Accepted Answer

A) Al - I 
B) Si - I 
C) Al - Cl 
D) Si - Cl 
E) Si - P 
A) Al - I 
B) Si - I 
C) Al - Cl 
D) Si - Cl 
E) Si - P

Question 11

The standard enthalpy of formation of ammonia at 25°C is -46.3 kJ/mol. Estimate the N-H bond enthalpy at this temperature. (Given: BE(N$\equiv$N)=941.4 kJ/mol, BE(H-H)= 436.4 kJ/mol)

Accepted Answer

A) 383 kJ/mol 
B) 475 kJ/mol 
C) 360 kJ/mol 
D) 391 kJ/mol 
E) 459 kJ/mol 
A) 383 kJ/mol 
B) 475 kJ/mol 
C) 360 kJ/mol 
D) 391 kJ/mol 
E) 459 kJ/mol

Question 12

Write a Lewis structure for the chlorite ion, ClO2-, that obeys the octet rule, showing all non-zero formal charges, and give the total number of resonance structures for ClO2- that obey the octet rule.

Accepted Answer

@#IMG-DLM& Total number of res

Question 13

The Lewis dot symbol for the S 2- ion is

Accepted Answer

A)    
B)    2- 
C) (S2-) 
D) 
 -2- 
E)    - 
A)    
B)    2- 
C) (S2-) 
D) 
 -2- 
E)    -

Question 14

Write the Lewis dot symbol for the sulfide ion.

Accepted Answer

The answer of Write the Lewis dot symbol for the...

Question 15

For which of these species does the best Lewis structure have two or more equivalent resonance structures?

Accepted Answer

A) HCO2- 
B) SCN- 
C) CNO- 
D) N3- 
E) CO2 
A) HCO2- 
B) SCN- 
C) CNO- 
D) N3- 
E) CO2

Question 16

The total number of bonding electrons in a molecule of formaldehyde (H2CO)is

Accepted Answer

A) 3. 
B) 4. 
C) 6. 
D) 8. 
E) 18. 
A) 3. 
B) 4. 
C) 6. 
D) 8. 
E) 18.

Question 17

Write the Lewis structure of boron trifluoride.

Accepted Answer

The answer of Write the Lewis structure of boron trifluoride....

Question 18

Which one of the following molecules has an atom with an expanded octet?

Accepted Answer

A) HCl 
B) AsCl5 
C) ICl 
D) NCl3 
E) Cl2 
A) HCl 
B) AsCl5 
C) ICl 
D) NCl3 
E) Cl2

Question 19

Dichloromethane, CH2Cl2, is an important solvent in synthetic chemistry. Write a Lewis structure for CH2Cl2.

Accepted Answer

Question 20

Which one of the following compounds does not follow the octet rule?

Accepted Answer

A) NF3 
B) CO2 
C) CF4 
D) Br2 
E) NO 
A) NF3 
B) CO2 
C) CF4 
D) Br2 
E) NO

Exam 9: Chemical Bonding I: the Covalent Bond

A nonpolar covalent bond (i.e., pure covalent)would form in which one of the following pairs of atoms?

Which one of the following is most likely to be an ionic compound?

Assuming the octet rule is obeyed, how many covalent bonds will a nitrogen atom form to give a formal charge of zero?

Write a Lewis structure for the nitrate ion, NO3-, showing all non-zero formal charges.

Which of the elements listed below has the greatest electronegativity?

What is the formal charge on the oxygen atom in N2O (the atomic order is N-N-O)?

Use the Born-Haber cycle to calculate the lattice energy of MgO (s)given the following data: Δ\DeltaΔ H(sublimation)Mg = 130 kJ/mol I1 (Mg)= 738.1 kJ/mol I2 (Mg)= 1450 kJ/mol Bond energy (O=O)= 498.7 kJ/mol EA (O)= 141 kJ/mol EA (O-)= -780 kJ/mol Δ\DeltaΔ H (MgO(s))= -601.8 kJ/mol

Assuming the octet rule is obeyed, how many covalent bonds will a carbon atom form to give a formal charge of zero?

Use the bond enthalpy data given to estimate the heat released when 6.50 g of nitrogen gas reacts with excess hydrogen gas to form ammonia at 25°C. BE(N ≡\equiv≡ N)= 941.4 kJ/mol BE(H-H)= 436.4 kJ/mol BE(N-H)= 393 kJ/mol

Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)?

The standard enthalpy of formation of ammonia at 25°C is -46.3 kJ/mol. Estimate the N-H bond enthalpy at this temperature. (Given: BE(N ≡\equiv≡ N)=941.4 kJ/mol, BE(H-H)= 436.4 kJ/mol)

Write a Lewis structure for the chlorite ion, ClO2-, that obeys the octet rule, showing all non-zero formal charges, and give the total number of resonance structures for ClO2- that obey the octet rule.

The Lewis dot symbol for the S 2- ion is

Write the Lewis dot symbol for the sulfide ion.

For which of these species does the best Lewis structure have two or more equivalent resonance structures?

The total number of bonding electrons in a molecule of formaldehyde (H2CO)is

Write the Lewis structure of boron trifluoride.

Which one of the following molecules has an atom with an expanded octet?

Dichloromethane, CH2Cl2, is an important solvent in synthetic chemistry. Write a Lewis structure for CH2Cl2.

Which one of the following compounds does not follow the octet rule?

Introduction

Atoms, Molecules, and Ions

Stoichiometry

Reactions in Aqueous Solution

Gases

Energy Relationships in Chemical Reactions

The Electronic Structure of Atoms

The Periodic Table

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Introduction to Organic Chemistry

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Thermodynamics

Redox Reactions and Electrochemistry

The Chemistry of Coordination Compounds

Nuclear Chemistry

Organic Polymerssynthetic and Natural

Filters

Write a Lewis structure for the nitrate ion, NO₃^-, showing all non-zero formal charges.

What is the formal charge on the oxygen atom in N₂O (the atomic order is N-N-O)?

Use the bond enthalpy data given to estimate the heat released when 6.50 g of nitrogen gas reacts with excess hydrogen gas to form ammonia at 25°C. BE(N $\equiv$ N)= 941.4 kJ/mol BE(H-H)= 436.4 kJ/mol BE(N-H)= 393 kJ/mol

The standard enthalpy of formation of ammonia at 25°C is -46.3 kJ/mol. Estimate the N-H bond enthalpy at this temperature. (Given: BE(N $\equiv$ N)=941.4 kJ/mol, BE(H-H)= 436.4 kJ/mol)

Write a Lewis structure for the chlorite ion, ClO₂^-, that obeys the octet rule, showing all non-zero formal charges, and give the total number of resonance structures for ClO₂^- that obey the octet rule.

The Lewis dot symbol for the S^2- ion is

The total number of bonding electrons in a molecule of formaldehyde (H₂CO)is

Dichloromethane, CH₂Cl₂, is an important solvent in synthetic chemistry. Write a Lewis structure for CH₂Cl₂.