Question 1

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 2F) All of the above
G) B) and D)

Question 2

Select the element whose Lewis symbol is correct.

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) B) and E)
G) A) and D)

Question 3

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.F) A) and B)
G) A) and C)

Question 4

Which of the following contains covalent bonds?

Accepted Answer

A)  BaO
B)  IBr
C)  Mg
D)  LiBr
E)  CuF) B) and C)
G) C) and D)

Question 5

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) 
2(g)  → H3C-CH3(g)    A) −296 kJ B) −51 kJ C) 51 kJ D) 296 kJ E) 381 kJ" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  −296 kJ
B)  −51 kJ
C)  51 kJ
D)  296 kJ
E)  381 kJF) A) and E)
G) B) and C)

Question 6

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) F) D) and E)
G) B) and C)

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

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.F) All of the above
G) None of the above

Question 10

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 2F) A) and D)
G) C) and E)

Question 11

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 moltenF) A) and E)
G) C) and D)

Question 12

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.F) None of the above
G) B) and E)

Question 13

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.F) A) and D)
G) B) and E)

Question 14

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 2F) A) and C)
G) C) and E)

Question 15

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 16

Which of the following elements is the most electronegative?

Accepted Answer

A)  S
B)  Ru
C)  Si
D)  Te
E)  CsF) A) and C)
G) B) and C)

Question 17

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.F) B) and E)
G) A) and E)

Question 18

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 pmF) A) and B)
G) B) and C)

Question 19

Select the element whose Lewis symbol is correct.

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) A) and D)
G) A) and C)

Question 20

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) F) A) and D)
G) A) and E)

Exam 9: Models of Chemical Bonding

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following contains covalent bonds?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

The melting points of metals are only moderately high because

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following elements is the most electronegative?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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)

Correct AnswerverifiedShow Answer

Select the element whose Lewis symbol is correct.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Select the element whose Lewis symbol is correct.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

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

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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)

Correct Answer
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