CHE 1401 - Fall 2013 - Chapter 8
Homework 8 (Chapter 8: Basic concepts of chemical bonding)
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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Of the possible bonds between carbon atoms (single, double, and triple), __________.
A) a single bond is stronger than a double bond B) a double bond is longer than a triple bond C) a double bond is stronger than a triple bond D) a single bond is stronger than a triple bond
E) a triple bond is longer than a single bond
1)
2) In the Lewis symbol for a sulfur atom, there are __________ paired and __________ unpaired electrons.
A) 4, 2 B) 2, 2 C) 0, 6 D) 5, 1 E) 2, 4
2)
3) Which atom can accommodate an octet of electrons, but doesn't necessarily have to accommodate an octet?
A) O B) N C) B D) C E) H
3)
4) Which of the following does not have eight valence electrons?
A) Rb+1 B) Xe C) Ti+4 D) Cl- E) Sr+1
4)
5) Given that the average bond energies for C-H and C-Br bonds are 413 and 276 kJ/mol, respectively, the heat of atomization of bromoform (CHBr3) is
__________ kJ/mol.
A) 1241 B) -1378 C) -689 D) 1378 E) 689
5)
6) Resonance structures differ by __________. A) placement of atoms only
B) placement of electrons only C) number of atoms only
D) number and placement of electrons E) number of electrons only
7) Using the Born-Haber cycle, the ΔHf° of KBr is equal to __________. A) ΔHf°[K (g)] + ΔHf°[Br (g)] + I1(K) + E(Br) - ΔHlattice
B) ΔHf°[K (g)] - ΔHf°[Br (g)] - I1(K) - E(Br) - ΔHlattice C) ΔHf°[K (g)] + ΔHf°[Br (g)] - I1 - E(Br) + ΔHlattice D) ΔHf°[K (g)] + ΔHf°[Br (g)] + I1(K) + E(Br) + ΔHlattice
E) ΔHf°[K (g)] - ΔHf°[Br (g)] + I1(K) - E(Br) + ΔHlattice
7)
8) In the nitrite ion (NO2-), __________. A) there are 20 valence electrons
B) both bonds are the same C) both bonds are double bonds
D) one bond is a double bond and the other is a single bond E) both bonds are single bonds
8)
9) Based on the octet rule, boron will most likely form a __________ ion.
A) B2+ B) B2- C) B1+ D) B3+ E)
B3-9)
10) The type of compound that is most likely to contain a covalent bond is __________.
A) held together by the electrostatic forces between oppositely charged ions B) a solid metal
C) one that is composed of only nonmetals
D) one that is composed of a metal from the far left of the periodic table and a nonmetal from the far right of the periodic table
E) There is no general rule to predict covalency in bonds.
10)
11) Of the atoms below, __________ is the least electronegative.
A) F B) Si C) Rb D) Ca E) Cl
11)
12) As the number of covalent bonds between two atoms increases, the distance between the atoms __________ and the strength of the bond between them __________. A) increases, increases B) decreases, decreases C) increases, decreases D) decreases, increases E) is unpredictable 12)
13) Bond enthalpy is __________. A) always positive
B) always negative
C) sometimes positive, sometimes negative D) always zero
E) unpredictable
13)
14) Of the molecules below, the bond in __________ is the most polar.
A) HI B) HF C) HBr D) H2 E) HCl
14)
15) The chloride of which of the following metals should have the greatest lattice energy? A) lithium B) rubidium C) potassium D) sodium E) cesium 15)
16) Which of the following names is/are correct for the compound TiO2? A) titanium dioxide and titanium (IV) oxide
B) titanium oxide
C) titanium (IV) dioxide
D) titanium oxide and titanium (IV) dioxide E) titanium (II) oxide
16)
17) Of the ions below, only __________ has a noble gas electron configuration.
A) I+ B) S3- C) K- D) O2+ E)
Cl-17)
18) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) CO2 B) CCl4 C) PCl3 D) ClF3 E) SO3
18)
19) Dynamite consists of nitroglycerine mixed with __________. A) damp KOH
B) solid carbon C) TNT
D) potassium nitrate
E) diatomaceous earth or cellulose
20) The Lewis structure of N2H2 shows __________. A) each nitrogen has one nonbonding electron pair
B) each nitrogen has two nonbonding electron pairs C) a nitrogen-nitrogen single bond
D) a nitrogen-nitrogen triple bond
E) each hydrogen has one nonbonding electron pair
20)
21) Most explosives are compounds that decompose rapidly to produce __________ products and a great deal of __________.
A) gaseous, gases B) solid, gas C) liquid, heat D) soluble, heat E) gaseous, heat 21)
22) For resonance forms of a molecule or ion, __________.
A) the observed structure is an average of the resonance forms
B) there cannot be more than two resonance structures for a given species C) one always corresponds to the observed structure
D) the same atoms need not be bonded to each other in all resonance forms E) all the resonance structures are observed in various proportions
22)
23) Which of the following names is/are correct for the compound SnCl4? A) tin (IV) tetrachloride
B) tin chloride
C) tin chloride and tin (II) tetrachloride D) tin tetrachloride and tin (IV) chloride
E) tin (II) chloride and tin (IV) chloride
23)
24) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) ICl5 B) NI3 C) SO2 D) SiF4 E) CO2
24)
25) Of the following, __________ cannot accommodate more than an octet of electrons.
A) P B) O C) As D) I E) S
25)
28) Of the bonds below, __________ is the least polar.
A) C, F B) Si, Cl C) Na, Cl D) Na, S E) P, S
28)
For the questions that follow, consider the BEST Lewis structures of the following oxyanions:
(i) NO2- (ii) NO3- (iii) SO32- (iv)SO42- (v)
BrO3-29) In which of the ions do all X-O bonds (X indicates the central atom) have the same length?
A) none B) all
C) (i) and (ii) D) (iii) and (v)
E) (iii), (iv), and (v)
29)
30) There can be four equivalent best resonance structures of __________.
A) (i) B) (ii) C) (iii) D) (iv) E) (v)
30)
31) Which of the following has eight valence electrons? A) Ti4+
B) Na+ C) Cl-D) Kr
E) all of the above
31)
32) The Lewis structure of the CO32- ion is __________. A)
B)
C)
D)
E)
33) The oxidation number of phosphorus in PF3 is __________.
A) +1 B) +2 C) +3 D) -2 E) -3
33)
34) Of the atoms below, __________ is the most electronegative.
A) F B) N C) Br D) Cl E) O
34)
35) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) SO2 B) SO32- C) NF3 D) CF4 E) BeH2
35)
36) Which of the following has the bonds correctly arranged in order of increasing polarity?
A) OF, BeF, MgF, NF B) MgF, BeF, NF, OF C) OF, NF, BeF, MgF
37) Why don't we draw double bonds between the Be atom and the Cl atoms in BeCl2?
A) That would result in more than eight electrons around each chlorine atom. B) That would result in the formal charges not adding up to zero.
C) That would give positive formal charges to the chlorine atoms and a negative formal charge to the beryllium atom.
D) There aren't enough electrons.
E) That would result in more than eight electrons around beryllium.
37)
38) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) SeF4 B) SiF4 C) CF4 D) PO43- E) NF3
38)
39) Which two bonds are most similar in polarity? A) BF and ClF
B) AlCl and IBr C) IBr and SiCl D) ClCl and BeCl
E) OF and ClF
39)
40) In ionic bond formation, the lattice energy of ions ________ as the magnitude of the ion charges _______ and the radii __________.
A) increases, increase, increase B) increases, decrease, decrease C) decreases, increase, increase D) increases, increase, decrease E) increases, decrease, increase
