Deck 9: Models of Chemical Bonding

Question 1

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

A)high melting point
B)high boiling point
C)brittleness
D)poor electrical conductor when solid
E)poor electrical conductor when molten

Answer 1

poor electrical conductor when molten

Question 2

The lattice energy for ionic crystals increases as the charge on the ions _____________ and the size of the ions __________________.

A)increases,increases
B)increases,decreases
C)decreases,increases
D)decreases,decreases
E)None of these is generally correct.

Answer 2

increases,decreases

Question 3

In which of these substances are the atoms held together by metallic bonding?

A)CO₂
B)Si
C)Br₂
D)S₈
E)Cr

Answer 3

Cr

Question 4

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

A)Mg(s)+ Cl₂(g) $\to$ MgCl₂(s)
B)Mg(g)+ 2Cl(g) $\to$ MgCl₂(s)
C)Mg²⁺(s)+ 2Cl^-(g) $\to$ MgCl₂(g)
D)Mg²⁺(g)+ 2Cl^-(g) $\to$ MgCl₂(s)
E)MgCl₂(aq) $\to$ MgCl₂(s)

Question 5

Select the compound with the lowest lattice energy.

A)CsBr(s)
B)NaCl(s)
C)SrO(s)
D)CaO(s)
E)KBr(s)

Question 6

Select the element whose Lewis symbol is correct.

A)a
B)b
C)c
D)d
E)e

Question 7

In which of these substances are the atoms held together by polar covalent bonding?

A)SrCl₂
B)CsCl
C)ClF
D)TiF₂
E)S₈

Question 8

Which of the following is an ionic compound?

A)H₂S
B)NH₃
C)I₂
D)KI
E)CCl₄

Question 9

Select the compound with the highest lattice energy.

A)CaS(s)
B)BaO(s)
C)NaI(s)
D)LiBr(s)
E)MgO(s)

Question 10

Select the correct formula for a compound formed from calcium and chlorine.

A)CaCl
B)CaCl₂
C)Ca₂Cl
D)Ca₂Cl₂
E)CaCl₃

Question 11

Select the element whose Lewis symbol is correct.

A)a
B)b
C)c
D)d
E)e

Question 12

Arrange the following bonds in order of increasing bond strength.

A)C-I < C-Br < C-Cl < C-F
B)C-F < C-Cl < C-Br < C-I
C)C-Br < C-I < C-Cl < C-F
D)C-I < C-Br < C-F< C-Cl
E)None of these orders is correct.

Question 13

For which of the following elements (in their normal,stable forms)would it be correct to describe the bonding as involving "electron pooling"?

A)hydrogen
B)helium
C)sulfur
D)iodine
E)aluminum

Question 14

Which of the following contains ionic bonding?

A)CO
B)SrF₂
C)Al
D)OCl₂
E)HCl

Question 15

Which of the following is a covalent compound?

A)Na₂O
B)CaCl₂
C)Cl₂O
D)CsCl
E)Al₂O₃

Question 16

Which of the following contains covalent bonds?

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

Question 17

Select the strongest bond in the following group.

A)C-S
B)C-O
C)C=C
D)C $\equiv$ N
E)C-F

Question 18

The lattice energy of CaF₂ is the energy change for which one,if any,of the following processes?

A)Ca²⁺(s)+ 2F^-(g) $\to$ CaF₂(g)
B)CaF₂(g) $\to$ CaF₂(s)
C)Ca(g)+ 2F(g) $\to$ CaF₂(s)
D)CaF₂(aq) $\to$ CaF₂(s)
E)None of these choices is correct.

Question 19

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

A)BaN
B)BaN₂
C)Ba₂N₃
D)Ba₂N
E)Ba₃N₂

Question 20

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?

A)HCl
B)Al
C)KBr
D)SiF₄
E)I₂

Question 21

Ionic bonding typically occurs when a ______________ bonds with a ______________.

Question 22

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

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

Question 23

Which of the following compounds displays the greatest ionic character in its bonds?

A)NO₂
B)CO₂
C)H₂O
D)HF
E)NH₃

Question 24

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

A)O > S > Ca > K > Rb
B)O > S > Ca > Rb > K
C)O > S > Rb > K > Ca
D)O > S > Rb > Ca > K
E)None of these orders is correct.

Question 25

In not more than three sentences,describe the electron arrangement responsible for bonding in solid SrCl₂.

Question 26

Which of the following elements is the least electronegative?

A)Si
B)Se
C)S
D)Sc
E)Sr

Question 27

When an atom is represented in a Lewis electron dot symbol,the element symbol represents ______________ and the dots represent ______________.

Question 28

Electronegativity is a measure of

A)the energy needed to remove an electron from an atom.
B)the energy released when an electron is added to an atom.
C)the magnitude of the negative charge on an electron.
D)the attraction by an atom for electrons in a chemical bond.
E)the magnitude of the negative charge on a molecule.

Question 29

Hydrogenation of double and triple bonds is an important industrial process.Calculate (in kJ)the standard enthalpy change $\Delta$ H° for the hydrogenation of ethyne (acetylene)to ethane.

Bond:
C-C
C $\equiv$ C
C-H
H-H

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

Question 30

Acetone can be easily converted to isopropyl alcohol by addition of hydrogen to the carbon-oxygen double bond.Calculate the enthalpy of reaction using the bond energies given.

A)-484 kJ
B)-366 kJ
C)-48 kJ
D)+48 kJ
E)+366 kJ

Question 31

Arrange aluminum,nitrogen,phosphorus and indium in order of increasing electronegativity.

A)Al < In < N < P
B)Al < In < P < N
C)In < Al < P < N
D)In < P < Al < N
E)None of these orders is correct.

Question 32

When one mole of each of the following liquids is burned,which will produce the most heat energy?

A)C₆H₁₄
B)C₅H₁₂
C)C₆H₁₄O
D)C₆H₁₂O
E)C₆H₁₀O₃

Question 33

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

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 34

Based on electronegativity trends in the periodic table,predict which of the following compounds will have the greatest % ionic character in its bonds.

A)H₂O
B)LiI
C)CaO
D)RbF
E)HCl

Question 35

Which of the following elements is the most electronegative?

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

Question 36

Which one of the following properties is least characteristic of substances composed of small,covalently-bonded molecules?

A)low melting point
B)low boiling point
C)weak bonds
D)poor electrical conductor when solid
E)poor electrical conductor when molten

Question 37

Covalent bonding typically occurs when a ______________ bonds with a ______________.

Question 38

Which of the following elements is the most electronegative?

A)Ne
B)Rb
C)P
D)I
E)Cl

Question 39

Nitrogen and hydrogen combine to form ammonia in the Haber process.Calculate (in kJ)the standard enthalpy change $\Delta$ H° for the reaction written below,using the bond energies given.

Bond:
N $\equiv$ N
H-H
N-H

A)-969 kJ
B)-204 kJ
C)-105 kJ
D)204 kJ
E)595 kJ

Question 40

Select the most polar bond amongst the following.

A)C-O
B)Si-F
C)Cl-F
D)C-F
E)C-I

Question 41

Covalently bonded substances do not necessarily exist as separate molecules.

Question 42

Bond energy increases as bond order increases,for bonding between a given pair of atoms.

Question 43

Using appropriate,real examples to illustrate your answer,describe the correlation between bond energy and bond length for a series of single bonds.

Question 44

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

Question 45

The lattice energy of large ions is greater in magnitude than that of small ions of the same charge.

Question 46

Using appropriate,real examples to illustrate your answer,describe the correlation between bond energy and bond length for a series of varying bond order.

Question 47

The more C-O and O-H bonds there are in a substance,the greater will be the amount of heat released when a fixed mass of the substance is burned.

Question 48

Oxygen difluoride is an unstable molecule that reacts readily with water.Calculate the bond energy of the O-F bond using the standard enthalpy of reaction and the bond energy data provided.

Question 49

In not more than three sentences,describe the electron arrangement responsible for bonding in Cl₂ molecules.

Question 50

A hypothetical ionic substance will not form merely because it has a high lattice energy.Explain why,using energy-based arguments.

Question 51

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

Question 52

Describe,with appropriate explanations,the key factors which affect the magnitude of the lattice energy of an ionic substance.

Question 53

Describe in brief how electronegativity values can be used to predict the percent ionic character of a bond between two atoms.

Question 54

The electrostatic energy of two charged particles is inversely proportional to the distance between them.

Question 55

Give a clear and concise definition of the term "electronegativity";i.e. ,what does it measure?

Question 56

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

Question 57

The electrostatic energy of two charged particles is inversely proportional to the square of the distance between them.

Question 58

No real bonds are 100% ionic in character.

Question 59

A single covalent bond consists of a single delocalized electron pair.

Question 60

Ethanol is sometimes used as an additive in oxygenated gasoline.Calculate its enthalpy of combustion using the bond energies given.