CHEMISTRY 1710 - Practice Exam #5 - SPRING 2014 (KATZ)
Name:___________________________________
Score:___________
This is a multiple choice exam. Choose the BEST answer from the choices
which are given and write the letter for your choice in the space provided. All
questions are equally weighted. Any specific reasoning or notes which lead to
your answer may be included in the space provided.
_____ 1. Which of the following contains ionic bonding? A) CO
C) Al
B) SrF2
D) OCl2
_____ 2. Which of the following contains covalent bonds? A) BaO
C) ClF
B) CsCl
D) Cu
_____ 3. Which of the following represents the Lewis structure for N?
A)
B)
C)
D)
_____ 4. Which of the following statements is TRUE?
A) An ionic bond is much stronger than most covalent bonds.
B) An ionic bond is formed through the sharing of electrons.
C) Solid ionic compounds at room temperature typically conduct electricity.
D) Once dissolved in water, ionic compounds rarely conduct electricity
_____ 5. Determine the chemical formula for the compound formed between Ca and N.
A) Ca2N3
B) Ca3N2
C) CaN2
D) CaN
_____ 6. Which of the following reactions is associated with the lattice energy of Li2O (ΔH°latt)?
A) Li2O(s) → 2 Li⁺(g) + O2⁻(g)
B) 2 Li⁺(aq) + O2⁻(aq) → Li2O(s)
C) 2 Li⁺(g) + O2⁻(g) → Li2O(s)
D) Li2O(s) → 2 Li⁺(aq) + O2⁻(aq)
_____ 7. Identify the compound with the highest magnitude of lattice energy.
A) NaCl
B) KCl
C) LiCl
D) CsCl
_____ 8. Place the following in order of increasing magnitude of lattice energy.
MgO
LiI
CaS
A) CaS < MgO < LiI
B) LiI < CaS < MgO
C) MgO < CaS < LiI
D) LiI < MgO < CaS
_____ 9. A triple covalent bond contains __________ of electrons.
A) 0 pairs
C) 2 pairs
B) 1 pair
D) 3 pairs
_____10. Identify the number of bonding pairs and lone pairs of electrons in water.
A) 1 bonding pair and 1 lone pair
C) 2 bonding pairs and 2 lone pairs
B) 1 bonding pair and 2 lone pairs
D) 2 bonding pairs and 1 lone pair
_____11. Place the following elements in order of increasing electronegativity.
Sr
N
Na
A) Sr < Na < N
B) Na < N < Sr
C) Sr < N < Na
D) N < Sr < Na
_____12. Which molecule or compound below contains an ionic bond?
A) CO2
B) NH4NO3
C) SiF4
D) OCl2
_____13. Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity.
A) Al < In < N < P
C) In < Al < P < N
B) Al < In < P < N
D) In < P < Al < N
_____14. Choose the best Lewis structure for XeI2.
A)
C)
B)
D)
_____15. Choose the best Lewis structure for NO3⁻.
A)
B)
C)
D)
_____16. Using Lewis structures and formal charge, which of the following ions is most stable?
OCN⁻
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"
ONC⁻
NOC⁻
A) OCN⁻
B) ONC⁻
C) NOC⁻
D) None of these ions are stable according to Lewis theory
_____17. Use the bond energies provided to estimate ΔH°rxn for the reaction below.
XeF2 + 2 F2 → XeF6
Bond Bond Energy (kJ/mol)
Xe-F 147
F-F 159
A) -429 kJ
B) +159 kJ
C) -270 kJ
D) +176 kJ
ΔH°rxn = ?
_____18. Which ionic compound would be expected to have the highest lattice energy?
A) Rb2O
B) SrO
C) In2O3
D) CO2
_____19. Of the following elements, which has the highest electronegativity?
A) S
B) Cl
C) Ti
D) Se
_____20. Select the Lewis structure in which formal charges are minimized for the periodate
anion, IO4-.
_____21. Determine the electron geometry (eg) and molecular geometry (mg) of CH3+1.
A) eg=tetrahedral, mg=tetrahedral
B) eg=tetrahedral, mg=trigonal pyramidal
C) eg=trigonal planar, mg=bent
D) eg=trigonal planar, mg=trigonal planar
_____22. Determine the electron geometry (eg) and molecular geometry (mg) of NCl3.
A) eg=tetrahedral, mg=tetrahedral
B) eg=linear, mg=trigonal planar
C) eg=trigonal planar, mg=bent
D) eg=tetrahedral, mg=trigonal pyramidal
_____23. Consider the molecule below. Determine the molecular geometry at each of the 2
labeled carbons.
A) C1 = tetrahedral, C2 = linear
B) C1 = trigonal planar, C2= bent
C) C1 = bent, C2 = trigonal planar
D) C1 = trigonal planar, C2 = tetrahedral
_____24. What is the molecular shape of ClO3F as predicted by the VSEPR theory? (Chlorine is
the central atom.)
A) trigonal pyramidal
B) square planar
C) square pyramidal
D) tetrahedral
_____25. Determine the electron geometry (eg) and molecular geometry (mg) of IF2-.
A) eg=tetrahedral, mg=bent
C) eg=trigonal planar, mg=linear
B) eg=trigonal planar, mg=bent
D) eg=trigonal bipyramidal, mg=linear
_____26. Place the following in order of decreasing X-A-X bond angle, where A represents the central
atom and X represents the outer atoms in each molecule.
N2O
NCl3
NO2⁻
A) NCl3 > NO2⁻ > N2O
B) NO2⁻ > N2O > NCl3
C) N2O > NO2⁻ > NCl3
D) NCl3 > N2O > NO2⁻
_____27. Which of the following molecules has a net dipole moment?
A) BeCl2
C) KrF2
B) SF2
D) CO2
_____28. Describe a pi bond.
A) side by side overlap of p orbitals
B) end to end overlap of p orbitals
C) s orbital overlapping with the end of a p orbital
D) overlap of two s orbitals
_____29 A molecule containing a central atom with sp hybridization has ______ geometry.
A) linear
B) trigonal bipyramidal
C) trigonal planar
D) tetrahedral
_____30. List the number of sigma bonds and pi bonds in a double bond.
A) 1 sigma, 1 pi
B) 2 sigma, 1 pi
C) 2 sigma, 2 pi
D) 1 sigma, 2 pi
_____31. How many of the following molecules contain at least one pi bond?
C2H6
Cl2CO C2Cl4
SeS3
A) 0
B) 1
C) 3
D) 4
_____32. Which one of the following statements about orbital hybridization is incorrect ?
A) The carbon atom in CH4 is sp3 hybridized
B) sp hybrid orbitals lie at 180° to each other.
C) The nitrogen atom in NH3 is sp2 hybridized
D) sp2 hybrid orbitals are coplanar, and at 120° to each other.
_____33. According to valence bond theory, the triple bond in ethyne (acetylene, C2H2) consists of
A) three σ bonds and no π bonds.
C) two σ bonds and one π bond.
B) one σ bond and two π bonds
D) no σ bonds and three π bonds.
_____34. What is the O-S-O bond angle in SO32-?
A) less than 109.5°
C) 120°
B) 109.5°
D) greater than 120°
_____35. Determine the shape (geometry) of PCl3 and then decide on the appropriate hybridization of
phosphorus in this molecule. (Phosphorus is the central atom.)
A) sp
C) sp3
B) sp2
D) sp3d
_____36. Give the change in conditions to go from a liquid to a gas.
A) increase heat or reduce pressure
C) cool or reduce pressure
B) increase heat or increase pressure
D) cool or increase pressure
_____37. What is the strongest type of intermolecular force acting between molecules of H2?
A) ion-dipole
C) dispersion
B) dipole-dipole
D) hydrogen bonding
_____38. Place the following compounds in order of increasing strength of intermolecular forces.
CO2
F2
NH2CH3
A) NH2CH3 < CO2 < F2
B) F2 < NH2CH3 < CO2
C) NH2CH3 < F2 < CO2
D) F2 < CO2 < NH2CH3
_____39. Place the following substances in order of increasing boiling point.
CH3CH2OH He
CH3OCH3
A) He < CH3OCH3 < CH3CH2OH
B) CH3CH2OH < He < CH3OCH3
C) CH3CH2OH < CH3OCH3 < He
D) CH3OCH3 < He < CH3CH2OH
_____40. Which is expected to have the highest magnitude of dispersion forces between molecules?
A) C3H8
C) F2
B) C12H26
D) Be Cl2
_____ 41. The heat of vaporization of water at 100°C is 40.66 kJ/mol. Calculate the quantity of heat that
is absorbed/released when 9.00 g of steam condenses to liquid water at 100°C.
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A) 20.3 kJ of heat are absorbed.
B) 20.3 kJ of heat are released.
C) 81.3 kJ of heat are absorbed.
D) 81.3 kJ of heat are released.
_____42. Calculate the total quantity of heat required to convert 25.0 g of liquid CCl4(l) from 35.0°C to
gaseous CCl4 at 76.8°C (the normal boiling point for CCl4). The specific heat of CCl4(l) is
0.857 J/(g · °C), its heat of fusion is 3.27 kJ/mol, and its heat of vaporization is 29.82 kJ/mol.
A) 0.896 kJ
B) 1.43 kJ
C) 5.74 kJ
D) 6.28 kJ