CHE 1401 - Spring 2013 - Chapter 8
Homework 8 (Chapter 8: Basic concepts of chemical bonding)
_______________________________________________________________________________
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 double bond is stronger than a triple bond
B) a single bond is stronger than a double bond
C) a triple bond is longer than a single bond
D) a double bond is longer than a triple bond
E) a single bond is stronger than a triple bond
1)
2) For resonance forms of a molecule or ion, __________.
A) one always corresponds to the observed structure
B) there cannot be more than two resonance structures for a given species
C) the same atoms need not be bonded to each other in all resonance forms
D) the observed structure is an average of the resonance forms
E) all the resonance structures are observed in various proportions
2)
3) Resonance structures differ by __________.
A) number and placement of electrons
B) number of atoms only
C) placement of atoms only
D) number of electrons only
E) placement of electrons only
3)
4) Which of the following names is/are correct for the compound SnCl4?
A) tin chloride
B) tin tetrachloride and tin (IV) chloride
C) tin (II) chloride and tin (IV) chloride
D) tin chloride and tin (II) tetrachloride
E) tin (IV) tetrachloride
4)
1
For the questions that follow, consider the BEST Lewis structures of the following oxyanions:
(i) NO2- (ii) NO3- (iii) SO32- (iv)SO42- (v) BrO35) 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)
5)
6) There can be four equivalent best resonance structures of __________.
A) (i)
B) (ii)
C) (iii)
D) (iv)
E) (v)
6)
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
7)
C) ΔHf°[K (g)] - ΔHf°[Br (g)] + I1(K) - E(Br) + ΔHlattice
D) ΔHf°[K (g)] - ΔHf°[Br (g)] - I1(K) - E(Br) - ΔHlattice
E) ΔHf°[K (g)] + ΔHf°[Br (g)] - I1 - E(Br) + ΔHlattice
8) Which of the following has the bonds correctly arranged in order of increasing
polarity?
A) NF, BeF, MgF, OF
B) BeF, MgF, NF, OF
C) OF, BeF, MgF, NF
D) OF, NF, BeF, MgF
E) MgF, BeF, NF, OF
8)
9) Of the atoms below, __________ is the most electronegative.
A) F
B) O
C) Br
D) Cl
9)
10) Of the molecules below, the bond in __________ is the most polar.
A) HI
B) HBr
C) HCl
D) HF
2
E) N
10)
E) H2
11) Most explosives are compounds that decompose rapidly to produce __________
products and a great deal of __________.
A) solid, gas
B) liquid, heat
C) soluble, heat
D) gaseous, gases
E) gaseous, heat
11)
12) Of the bonds below, __________ is the least polar.
A) Na, Cl
B) Si, Cl
C) P, S
D) Na, S
12)
E) C, F
13) In the nitrite ion (NO2-), __________.
A) there are 20 valence electrons
B) both bonds are the same
C) both bonds are single bonds
D) both bonds are double bonds
E) one bond is a double bond and the other is a single bond
13)
14) In the Lewis symbol for a sulfur atom, there are __________ paired and
__________ unpaired electrons.
A) 2, 2
B) 5, 1
C) 2, 4
D) 4, 2
E) 0, 6
14)
15) Bond enthalpy is __________.
A) always positive
B) sometimes positive, sometimes negative
C) always negative
D) always zero
E) unpredictable
15)
16) 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
16)
__________ kJ/mol.
A) 1378
B) -1378
C) 689
D) 1241
E) -689
17) Which atom can accommodate an octet of electrons, but doesn't necessarily
have to accommodate an octet?
A) N
B) C
C) O
D) H
E) B
3
17)
18) Which of the following has eight valence electrons?
A) Kr
B) Ti4+
18)
C) Na+
D) ClE) all of the above
19) In ionic bond formation, the lattice energy of ions ________ as the magnitude of
the ion charges _______ and the radii __________.
A) increases, decrease, decrease
B) increases, decrease, increase
C) decreases, increase, increase
D) increases, increase, increase
E) increases, increase, decrease
19)
20) Why don't we draw double bonds between the Be atom and the Cl atoms
in BeCl2?
A) That would give positive formal charges to the chlorine atoms and a
negative formal charge to the beryllium atom.
B) That would result in the formal charges not adding up to zero.
C) That would result in more than eight electrons around beryllium.
D) That would result in more than eight electrons around each chlorine atom.
E) There aren't enough electrons.
20)
21) Which two bonds are most similar in polarity?
A) OF and ClF
B) IBr and SiCl
C) BF and ClF
D) AlCl and IBr
E) ClCl and BeCl
21)
22) The chloride of which of the following metals should have the greatest lattice
energy?
A) sodium
B) cesium
C) lithium
D) rubidium
E) potassium
22)
23) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) PO43B) SeF4
C) CF4
D) SiF4
E) NF3
23)
4
24) 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
24)
25) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) SO2
B) NF3
C) CF4
D) BeH2
E) SO32-
25)
26) Of the following, __________ cannot accommodate more than an octet of
electrons.
A) O
B) S
C) P
D) As
E) I
26)
27) Which of the following names is/are correct for the compound TiO2?
A) titanium oxide
B) titanium (II) oxide
C) titanium (IV) dioxide
D) titanium oxide and titanium (IV) dioxide
E) titanium dioxide and titanium (IV) oxide
27)
28) The Lewis structure of N2H2 shows __________.
A) a nitrogen-nitrogen single bond
B) each nitrogen has two nonbonding electron pairs
C) each nitrogen has one nonbonding electron pair
D) each hydrogen has one nonbonding electron pair
E) a nitrogen-nitrogen triple bond
28)
29) Which of the following does not have eight valence electrons?
A) Xe
B) ClC) Sr+1
D) Rb +1
29)
E) Ti+4
30) The type of compound that is most likely to contain a covalent bond is
__________.
A) a solid metal
B) held together by the electrostatic forces between oppositely charged ions
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.
5
30)
31) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) SO3
B) CCl4
C) PCl3
D) ClF3
E) CO 2
31)
32) Of the ions below, only __________ has a noble gas electron configuration.
A) S3B) I+
C) KD) O 2+
E) Cl-
32)
33) The central atom in __________ does not violate the octet rule.
A) KrF2
B) XeF4
C) ICl4D) CF4
33)
34) The electron configuration [Kr]4d 10 represents __________.
A) Sr+2
B) Ag+1
C) Rb +1
D) Sn+2
E) SF4
34)
E) Te+2
35) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) NI3
B) SiF4
C) SO2
D) CO2
E) ICl5
35)
36) The oxidation number of phosphorus in PF3 is __________.
A) +2
B) -3
C) +1
D) -2
36)
E) +3
37) Based on the octet rule, boron will most likely form a __________ ion.
A) B3B) B1+
C) B2+
D) B3+
E) B2-
37)
38) Dynamite consists of nitroglycerine mixed with __________.
A) solid carbon
B) diatomaceous earth or cellulose
C) potassium nitrate
D) TNT
E) damp KOH
38)
39) The Lewis structure of the CO32- ion is __________.
39)
A)
6
B)
C)
D)
E)
40) Of the atoms below, __________ is the least electronegative.
A) Ca
B) Rb
C) Cl
D) F
7
40)
E) Si