Question 1

When two atoms form a covalently-bonded diatomic molecule, the distance between the nuclei at which the potential energy is at a minimum is called

Accepted Answer

A) the bond energy. 
B) the bond length. 
C) the molecular diameter. 
D) the covalent radius. 
E) the covalent diameter. 
A) the bond energy. 
B) the bond length. 
C) the molecular diameter. 
D) the covalent radius. 
E) the covalent diameter.

Question 2

Select the correct formula for a compound formed from barium and nitrogen.

Accepted Answer

A) BaN 
B) BaN 2 
C) Ba 2N 3 
D) Ba 2N 
E) Ba 3N 2 
A) BaN 
B) BaN 2 
C) Ba 2N 3 
D) Ba 2N 
E) Ba 3N 2

Question 3

Select the element whose Lewis symbol is correct.

Accepted Answer

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

Question 4

Combustion of a fat will release more energy than combustion of an equal mass of carbohydrate because

Accepted Answer

A) fats contain more bonds to oxygen than carbohydrates. 
B) fats contain fewer bonds to oxygen than carbohydrates. 
C) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the carbon-oxygen and oxygen-hydrogen bonds in the reaction products (carbon dioxide and water). 
D) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the bonds in carbohydrates. 
E) fats have higher molar masses than carbohydrates. 
A) fats contain more bonds to oxygen than carbohydrates. 
B) fats contain fewer bonds to oxygen than carbohydrates. 
C) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the carbon-oxygen and oxygen-hydrogen bonds in the reaction products (carbon dioxide and water). 
D) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the bonds in carbohydrates. 
E) fats have higher molar masses than carbohydrates.

Question 5

The diameter of a chloride ion is 362 pm, and the diameter of a potassium ion is 276 pm. What is the distance between the nuclei of adjacent chloride and potassium ions in solid potassium chloride?

Accepted Answer

A) 1276 pm 
B) 638 pm 
C) 319 pm 
D) 181 pm 
E) 138 pm 
A) 1276 pm 
B) 638 pm 
C) 319 pm 
D) 181 pm 
E) 138 pm

Question 6

In which of the following processes does the enthalpy change (ΔH) directly represent the magnitude of the lattice energy of KCl(s)?

Accepted Answer

A) Cl 2(g)+ 2K(s)→ 2KC (s) 
B) KCl(s)→ K +(aq)+ Cl − (aq) 
C) KCl(s)→ K +(g)+ Cl −(g) 
D) KCl(s)→ K(s)+ Cl −(g) 
E) KCl(s)→ K(s)+ Cl(g) 
A) Cl 2(g)+ 2K(s)→ 2KC (s) 
B) KCl(s)→ K +(aq)+ Cl − (aq) 
C) KCl(s)→ K +(g)+ Cl −(g) 
D) KCl(s)→ K(s)+ Cl −(g) 
E) KCl(s)→ K(s)+ Cl(g)

Question 7

Which of the following period 3 chlorides would be expected to have the highest melting point?

Accepted Answer

A) MgCl 2 
B) AlCl 3 
C) SiCl 4 
D) PCl 3 
E) SCl 2 
A) MgCl 2 
B) AlCl 3 
C) SiCl 4 
D) PCl 3 
E) SCl 2

Question 8

Electronegativities on Pauling's scale are calculated from ionization energies and electron affinities.

Accepted Answer

A) True 
 B)False

Question 9

Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.

Accepted Answer

A) S > As > Rb > Ca 
B) S > As > Ca > Rb 
C) As > S > Rb > Ca 
D) As > S > Ca > Rb 
E) None of these choices are correct. 
A) S > As > Rb > Ca 
B) S > As > Ca > Rb 
C) As > S > Rb > Ca 
D) As > S > Ca > Rb 
E) None of these choices are correct.

Question 10

Quartz (SiO2) is a solid with a melting point of 1550 °C. The bonding in quartz is best described as

Accepted Answer

A) lattice energy. 
B) network attractions. 
C) ionic bonding. 
D) covalent bonding. 
E) metallic bonding. 
A) lattice energy. 
B) network attractions. 
C) ionic bonding. 
D) covalent bonding. 
E) metallic bonding.

Question 11

Select the element whose Lewis symbol is correct.

Accepted Answer

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

Question 12

Which of the following contains covalent bonds?

Accepted Answer

A) BaO 
B) IBr 
C) Mg 
D) LiBr 
E) Cu 
A) BaO 
B) IBr 
C) Mg 
D) LiBr 
E) Cu

Question 13

Hydrogenation of double and triple bonds is an important industrial process. Calculate (in kJ) the standard enthalpy change ΔH° for the hydrogenation of ethyne (acetylene) to ethane. H-C≡C-H(g) + 2H2(g) → H3C-CH3(g)

Accepted Answer

A) −296 kJ 
B) −51 kJ 
C) 51 kJ 
D) 296 kJ 
E) 381 kJ 
A) −296 kJ 
B) −51 kJ 
C) 51 kJ 
D) 296 kJ 
E) 381 kJ

Question 14

The melting points of metals are only moderately high because

Accepted Answer

A) metallic bonding is weak. 
B) metals have fewer bonding electrons than nonmetals. 
C) metals also have relatively low boiling points. 
D) the melting process does not break the metallic bonds. 
E) metals prefer to be bonded to nonmetals. 
A) metallic bonding is weak. 
B) metals have fewer bonding electrons than nonmetals. 
C) metals also have relatively low boiling points. 
D) the melting process does not break the metallic bonds. 
E) metals prefer to be bonded to nonmetals.

Question 15

Which one of the following properties is least characteristic of typical ionic compounds?

Accepted Answer

A) High melting point 
B) High boiling point 
C) Brittleness 
D) Poor electrical conductor when solid 
E) Poor electrical conductor when molten 
A) High melting point 
B) High boiling point 
C) Brittleness 
D) Poor electrical conductor when solid 
E) Poor electrical conductor when molten

Question 16

The majority of elements are good electrical conductors when in solid form.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following elements is the most electronegative?

Accepted Answer

A) S 
B) Ru 
C) Si 
D) Te 
E) Cs 
A) S 
B) Ru 
C) Si 
D) Te 
E) Cs

Question 18

The lattice energy is the energy released when separated ions in the gas phase combine to form ionic molecules in the gas phase.

Accepted Answer

A) True 
 B)False

Question 19

Analysis of an unknown substance showed that it has a high boiling point and is brittle. It is an insulator as a solid but conducts electricity when melted. Which of the following substances would have those characteristics?

Accepted Answer

A) HCl 
B) Al 
C) KBr 
D) SiF 4 
E) I 2 
A) HCl 
B) Al 
C) KBr 
D) SiF 4 
E) I 2

Question 20

The lattice energy of MgCl2 is the energy change for which one of the following processes?

Accepted Answer

A) Mg( s)+ Cl 2( g)→ MgCl 2( s) 
B) Mg( g)+ 2Cl( g)→ MgCl 2( s) 
C) Mg 2+( s)+ 2Cl −( g)→ MgCl 2( g) 
D) Mg 2+( g)+ 2Cl −( g)→ MgCl 2( s) 
E) MgCl 2( aq)→ MgCl 2( s) 
A) Mg( s)+ Cl 2( g)→ MgCl 2( s) 
B) Mg( g)+ 2Cl( g)→ MgCl 2( s) 
C) Mg 2+( s)+ 2Cl −( g)→ MgCl 2( g) 
D) Mg 2+( g)+ 2Cl −( g)→ MgCl 2( s) 
E) MgCl 2( aq)→ MgCl 2( s)

Exam 9: Models of Chemical Bonding

When two atoms form a covalently-bonded diatomic molecule, the distance between the nuclei at which the potential energy is at a minimum is called

Select the correct formula for a compound formed from barium and nitrogen.

Select the element whose Lewis symbol is correct.

Combustion of a fat will release more energy than combustion of an equal mass of carbohydrate because

The diameter of a chloride ion is 362 pm, and the diameter of a potassium ion is 276 pm. What is the distance between the nuclei of adjacent chloride and potassium ions in solid potassium chloride?

In which of the following processes does the enthalpy change (ΔH) directly represent the magnitude of the lattice energy of KCl(s)?

Which of the following period 3 chlorides would be expected to have the highest melting point?

Electronegativities on Pauling's scale are calculated from ionization energies and electron affinities.

Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.

Quartz (SiO2) is a solid with a melting point of 1550 °C. The bonding in quartz is best described as

Select the element whose Lewis symbol is correct.

Which of the following contains covalent bonds?

Hydrogenation of double and triple bonds is an important industrial process. Calculate (in kJ) the standard enthalpy change ΔH° for the hydrogenation of ethyne (acetylene) to ethane. H-C≡C-H(g) + 2H2(g) → H3C-CH3(g)

The melting points of metals are only moderately high because

Which one of the following properties is least characteristic of typical ionic compounds?

The majority of elements are good electrical conductors when in solid form.

Which of the following elements is the most electronegative?

The lattice energy is the energy released when separated ions in the gas phase combine to form ionic molecules in the gas phase.

Analysis of an unknown substance showed that it has a high boiling point and is brittle. It is an insulator as a solid but conducts electricity when melted. Which of the following substances would have those characteristics?

The lattice energy of MgCl2 is the energy change for which one of the following processes?

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and Reaction Direction

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Quartz (SiO₂) is a solid with a melting point of 1550 °C. The bonding in quartz is best described as

Hydrogenation of double and triple bonds is an important industrial process. Calculate (in kJ) the standard enthalpy change ΔH° for the hydrogenation of ethyne (acetylene) to ethane. H-C≡C-H(g) + 2H₂(g) → H₃C-CH₃(g)

The lattice energy of MgCl₂ is the energy change for which one of the following processes?