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Molecular Geometry Questions

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					Chemical Bonding

   1. Which of the following pairs of atoms are least likely to form an ionic compound?
          a. Ni, O
          b. Na, F
          c. Cu, Cl
          d. Li, Mg
          e. Li, F
   2. The bond in dinitrogen (N2) is a:
          a. double bond.
          b. single bond.
          c. triple bond.
          d. lone pair.
          e. none of the above
   3. Which of the following formulas are incorrect on the basis of simple Lewis dot
      structures?
          a. LiCl
          b. MgO
          c. Na2O
          d. CO2
          e. none of these
   4. Which of the following bonds is most polar?
          a. H-F
          b. H-Cl
          c. H-H
          d. F-F
          e. H-I
   5. What type of hybrid orbital is present in methane (CH4)?
          a. sp2
          b. sp3
          c. sp3d
          d. sp
          e. sp3d2
   6. Which of the following molecules requires two resonance hybrid Lewis structures
      to account for the bonding?
          a. SO2
          b. CO2
          c. O2
          d. CH4
          e. C2H4
   7. The formal oxidation number of nitrogen in ammonia is:
          a. +3
          b. -1
          c. -4
          d. +1
          e. -3
8. The Lewis structure for CO2 is:




9. Which of the following pairs of atoms are most likely to form a covalent
    compound?
       a. Ni, O
       b. Na, F
       c. Cu, Cl
       d. C, O
       e. Li, F
10. The number of valence shell electrons in chlorine is:
       a. 17
       b. 2
       c. 5
       d. 7
       e. 4
11. The bond in oxygen (O2) is a:
       a. double bond.
       b. single bond.
       c. triple bond.
       d. lone pair.
       e. none of the above
12. Which of the following oxides is ionic?
       a. XeO3
       b. Y2O3
       c. SO2
       d. N2O
       e. P2O5
13. What is the formal charge on carbon in the preferred structure of CO2?
       a. 0
       b. -1
       c. +2
       d. -3
       e. +4
14. What is the oxidation number of I in NaIO3?
       a. -1
       b. +6
       c. +5
       d. +4
       e. -2
15. Given the following table of bond enthalpies:


                     average bond       bond enthalpy (kJ/mol)

                          C-H                      413

                          C-C                      348

                          C-N                      293

                          N-H                      391

                          H-H                      436

                          N-N                      163

                          O-H                      463

                          C=C                      614

                    C-N (triple bond)              891


16. Calculate the    H for the following reaction in the gas phase:
                         17. HCN(g) + 2H2(g) --> CH3NH2(g)
       a. -736 kJ
       b. -551 kJ
       c. -138 kJ
       d. +230 kJ
       e. +275 kJ
18. Which of the following IIIA family members should form the fluoride molecule
    with the highest lattice energy?
       a. AlF3
       b. GaF3
        c. InF3
        d. TlF3
        e. TlF
19. In which of the following molecules are the bonds most polar?
        a. H2
        b. HF
        c. CH4
        d. NH3
        e. H2O
20. Which of the pattern does not obey the octet rule?




21. Which of the following Lewis structures is least plausible?
22. The total number of electron pairs in the valence shell of Se in an SeF4 molecule
    is:
        a. 4 pairs, all bonding.
        b. 5 pairs, 4 bonding and 1 non-bonding.
        c. 6 pairs, 4 bonding and 2 non-bonding.
        d. 8 pairs, 4 bonding and 4 non-bonding.
        e. 17 pairs, 4 bonding and 13 non-bonding.
23. Which of the following could be the atom X in the following neutral (uncharged)
    molecule?




        a. H
        b. F
        c. C
        d. N
        e. O
24. The number of bonding electron pairs in the best Lewis structure of CS2 is:
        a. 1
        b. 2
        c. 3
        d. 4
        e. 5
25. The number of equivalent resonance structures connected with the best Lewis
    structure of SO3 is:
        a. 0
       b. 1
       c. 2
       d. 3
       e. 4
26. Atom X in the structure below is most likely:




       a. Cl
       b. S
       c. P
       d. Si
       e. Al
27. The symbols and respective electronegativities for elements in a hypothetical
    universe are given in the table below:


                          element    electronegativities

                             L               2.0

                             M               3.5

                             Q               0.9

                             R               2.5


28. Which of the following bonds is least polar (i.e. most nonpolar)?
      a. L-R
      b. M-L
      c. Q-M
      d. R-Q
      e. M-R
29. Which molecule has one pair of nonbonding electrons on the central atom?
      a. PCl3
      b. CO2
      c. SO3
      d. BF3
      e. SF2
30. What is the oxidation number and formal charge of iodine in the IF4+ ion?
                      oxidation state (number)      formal charge

                (a)                 -1                    -1

                (b)                 +1                    +5

                (c)                 +3                      0

                (d)                 +5                    +1

                (e)                 +5                    +5


31. Given the following table of bond energies, determine       H for the reaction,

                              CO(g) + 2H2(g) --> CH3OH(g)


                             bond          energy (kJ/mol)

                              C-O                 358

                             C=O                  799

                       C-O (triple bond)          1072

                              H-H                 436

                              C-H                 413

                              O-H                 463


       a. -830 kJ
       b. -557 kJ
       c. -552 kJ
       d. -389 kJ
       e. -116 kJ
32. Which of the following is the best electron-dot description for sulfur dioxide,
    SO2?
33. Hydrogen reacts with both active metals and nonmetals, e.g.

                             (1) H2(g) + 2Na(s) --> 2NaH(s)

                             (2) H2(g) + Cl2(g) --> 2HCl(g)

   Consider the following statements pointing out possible similarities between these
   two reactions:

       1.   The products of the two reactions are covalent molecules.
       2.   The products of the two reactions are ionic species.
       3.   Both reactions involve oxidation-reduction.
       4.   The oxidation number of hydrogen decreases in reaction (1) and increases
            in reaction (2).

   Which of these are correct?

              a. 1, 3 and 4
              b. 2, 3 and 4
              c. 1 and 3
              d. 3 and 4
              e. only 3
34. Which of the following compounds has the largest lattice energy in the crystal
    state?
               a. LiCl
               b. NaBr
               c. MgI2
               d. CaO
               e. There is not enough information to answer this question.
35. The crystal lattice energy can be determined by means of a Born-Haber cycle, in
    which several reactions are combined according to Hess' Law. In applying this
    procedure to the lattice energy of KBr, the following reactions are combined:


                        (1)         K(s) --> K(g)

                        (2)       1/2Br2(l) --> Br(g)

                        (3)       K(g) --> K+(g) + e-

                        (4)      Br(g) + e- --> Br-(g)

                        (5)   K(s) + 1/2Br2(l) --> KBr(s)


36. For which of the above reactions is H (or E) < 0?
         . All 5 reactions have H < 0
        a. Reactions 2, 4 and 5
        b. Reactions 4 and 5
        c. Reactions 2 and 4
        d. Only reaction 4
37. Which of the following will have the largest dipole moment?
         . HF
        a. HCl
        b. HBr
        c. HI
        d. F2
38. CO2 is a nonpolar molecular (µ=0) whereas SO2 is polar (µ=1.62 D). This
    difference is due to the fact that:
         . C and O have approximately the same electronegativity while S and O
            have different electronegativities.
        a. CO2 has an even number of double bonds whereas SO2 has an odd number
            of double bonds.
        b. C and O are in different groups whereas S and O are in the same group.
        c. the C-O bond is nonpolar while the S-O bond is polar.
        d. CO2 is linear whereas SO2 is not linear.
39. Which of the following molecules contains a covalent triple bond?
         . CO2
        a. SO3
        b. I2
        c. NH3
       d. N2
40. How many non-bonding electrons are located on the central atom of ICl4-?
        . 0
       a. 1
       b. 2
       c. 4
       d. 6
41. The bonds in carbon dioxide are
        . single bonds
       a. ionic bonds
       b. triple bonds
       c. double bonds
       d. none of these
42. The octet rule does not apply to
        . F
       a. O
       b. Cl
       c. N
       d. H
43. Which of the following bonds has the largest dipole moment?
        . Cl-Cl
       a. Cl-Br
       b. H-F
       c. H-I
44. Which of the following is a non-polar covalent compound?
        . CH4
       a. HCN
       b. CH3CN
       c. HCl
       d. NaCl
45. How many valence electrons does a nitrogen atom possess?
        . 3
       a. 4
       b. 5
       c. 6
       d. 0
46. The oxidation number of sulfur in SF6 is
        . +1
       a. -2
       b. -1
       c. +6
       d. 0
47. What is the state of hybridization of the carbon atoms in ethylene, C2H4?
        . sp2
       a. sp
       b. sp3
        c. sp3d2
        d. none of these
48. Which one of the following statements is incorrect?
         . The electrons involved in pi bonding are more delocalized in benzene than
            in ethylene.
        a. The bond order of the carbon - carbon bond in ethane, C2H6 , is two.
        b. Pi orbitals involve the overlap of un-hybridized p atomic orbitals.
        c. 2s atomic orbitals tend to be lower in energy than 2p orbitals.
49. The type(s) of bonding present in a sample of sodium nitrate, NaNO3, are:
         . covalent bonds only.
        a. ionic bonds only.
        b. metallic bonds only.
        c. covalent and ionic bonds.
        d. ionic and metallic bonds.
50. Which of the following species is best described by a Lewis structure involving
    resonance?
         . CO32-
        a. PO43-
        b. HSO4- (H bonded to O)
        c. All of the above are best described by resonance.
        d. None of (a)-(c).
51. Which of the following molecules has a non-zero dipole moment?
         . Cl2O
        a. I2
        b. BF3
        c. CO2
        d. SF6
52. How many lone (unshared) pairs are there in the best Lewis structure of ClF3?
         . 11
        a. 10
        b. 9
        c. 8
        d. 7
53. Which of the following compounds (or ions) contains an atom that does NOT
    follow the octet rule?
         . BrF3
        a. CBr4
        b. NO+
        c. BF4-
        d. NCl3
54. What is atom X in the Lewis structure of the following dianion?
         . Xe
        a. Cl
        b. S
        c. N
        d. C
55. How many electron pairs are there in the Lewis structure of SF6? Include all
    shared pairs and all unshared pairs.
         . 8
        a. 16
        b. 24
        c. 48
        d. 56
56. Which of the following elements forms bonds with fluorine that are the most
    covalent?
         . Al
        a. Ca
        b. O
        c. P
        d. Se
57. Which of the following ionic compounds has the largest lattice energy?
         . NaCl
        a. NaI
        b. KI
        c. MgO
        d. MgS
58. Which of the following substances is expected to involve the most ionic bonding?
         . LiF
        a. LiCl
        b. CH4
        c. Cl2
        d. PF6
59. The oxidation number of carbon in carbon monoxide (CO) is:
         . +4
        a. -2
        b. +1
        c. +2
        d. none of these
60. orbital overlap involves:
         . "end-on" bonding with s orbitals.
        a. "sideways" approach of pairs of p orbitals.
        b. overlap of an s with a p orbital.
        c. production of a bonding but not an antibonding orbital.
        d. None of the above.
61. Given that the electron configuration of carbon is [He]2s22p2 and chlorine is
    [Ne]3s23p5, how many lone pairs are on the C atom in CHCl3?
         . 0
        a. 4
        b. 2
        c. 1
        d. 6
62. Given the electronic configuration of sulfur is [Ne]3s23p4, the hybrid orbital
    involved in bonding in SF6 is:
         . sp3
        a. sp2
        b. sp2d2
        c. sp3d5
        d. sp3d2
63. The C=C double bond in ethene (or ethylene), C2H4, is composed of:
         . two bonds.
        a. 3p3 hybridization.
        b. two sigma bonds.
        c. one bond + one sigma bond.
        d. only unhybridized p orbitals.
64. Which of the following statements are true?
         . The number of MO's in a molecule equals twice the number of constituent
            atomic orbitals.
        a. As bonding MO's become more stable, antibonding MO's become equally
            less stable.
        b. In MO's, the number of bonding electrons equals the number of
            antibonding electrons.
        c. Each bonding MO can accomodate only one electron.
        d. None of the above.
65. What is the hybridization of phosphorus in PF5?
         . sp
        a. sp2
        b. sp3
        c. sp3d
        d. sp3d2
66. Indicate the number and kinds of bonds present in HCN.
         . 1 sigma and 1
        a. 1 sigma and 2
        b. 1 sigma and 3
        c. 2 sigma and 1
        d. 2 sigma and 2
67. According to the valence-bond theory, which two orbitals overlap to form the
    covalent bond in H-Cl?
        . s, s
       a. s, p
       b. s, d
       c. s, dz
       d. none of the above
68. What is the hybrid orbital diagram for boron in BF3?




69. Given the following table of bond enthalpies:


                    average bond      bond enthalpy (kJ/mol)

                         O-H                        463

                         H-H                        436

                         C-H                        413

                         N-N                        163

                         O-N                        201
                             N-H                      391

                             C-C                      348

                             N=N                      418

                     C-N (triple bond)                891


 70. Calculate the      H for the following reaction in the gas phase.



 71.
          .   -30. kJ
         a.   +289 kJ
         b.   -289 kJ
         c.   +493 kJ
         d.   -493 kJ




Answers
 1. D
 2. C
 3. E
 4. A
 5. B
 6. A
 7. E
 8. A
 9. D
 10. D
 11. A
 12. B
 13. A
 14. C
 15. C
 16. A
 17. B
 18. C
 19. A
 20. B
 21. E
 22. D
 23. D
   24. B
   25. A
   26. A
   27. D
   28. E
   29. B
   30. D
   31. D
   32. C
   33. A
   34. E
   35. E
   36. D
   37. D
   38. E
   39. C
   40. A
   41. C
   42. D
   43. A
   44. B
   45. D
   46. A
   47. A
   48. A
   49. A
   50. C
   51. C
   52. C
   53. D
   54. A
   55. D
   56. B
   57. A
   58. E
   59. D
   60. B
   61. D
   62. E
   63. B
   64. E
   65. E




Molecular Geometry Questions
1. On the basis of the VSEPR model, which of the following molecules is linear?
       a. H2O
       b. BF3
       c. BeF2
       d. CH4
       e. none of these
2. The molecular shape of H3O+ is:
       a. linear.
       b. planar.
       c. see-saw.
       d. trigonal planar.
       e. trigonal pyramidal.
3. Which of the following is a planar molecule or ion?




4. Which of the following molecules or ions is not linear?
     The next three questions refer to the molecule OXeF4 with a Lewis dot structure
                                       shown below.




5. The formal charge on the Xe atom is:
      a. -2
      b. -1
      c. 0
      d. +1
      e. +2
6. The geometry of the OXeF4 molecule is:
      a. trigonal bipyramidal.
      b. octahedral.
      c. square pyramidal.
      d. square planar.
      e. none of the above.
7. The number of bonding pair-to-bonding pair repulsions in OXeF4 is:
      a. 0
      b. 2
      c. 4
      d. 8
      e. 12
8. The molecular shape of SeF4 is:
      a. see-saw.
          b. square planar.
          c. tetrahedral.
          d. square pyramidal.
          e. impossible to predict.
9.    Which of the following hybrid orbitals forms bond angles of approximately 109o?
          a. sp
          b. sp2
          c. sp3
          d. sp3d
          e. sp3d2
10.   When the molecules H2O, CH4, and NH3 are arranged in order of increasing bond angle,
      the correct sequence is:
          a. H2O, CH4, NH3
          b. H2O, NH3, CH4
          c. NH3, H2O, CH4
          d. CH4, NH3, H2O
          e. CH4, H2O, NH3
11.   Which of the following molecules has the smallest angle between adjacent bonds?
          a. CO2
          b. CH4
          c. H2O
          d. NH3
          e. PH3
12.   The shape of ICl4- is:
          a. octahedral.
          b. see saw.
          c. square planar.
          d. tetrahedral.
          e. square pyramidal.
13.   What are the approximate values of the bond angles, a and b, in the ion illustrated below?




       a. a is ~90o and b is ~90o
       b. a is ~109o and b is ~109o
       c. a is ~109o and b is ~120o
       d. a is ~120o and b is ~109o
       e. a is ~90o and b is ~180o
14. The molecules NF3, BF3, and ClF3 have similar molecular formulas but different
    molecular geometries. Use VSEPR to predict their molecular shapes.
       a. NF3 trigonal pyramidal; BF3 trigonal planar; ClF3 T-shaped
       b. NF3 T-shaped; BF3 trigonal planar; ClF3 trigonal pyramidal
       c. NF3 trigonal planar; BF3 T-shaped; ClF3 trigonal pyramidal
       d. NF3 T-shaped; BF3 trigonal pyramidal; ClF3 trigonal planar
       e. NF3 trigonal pyramidal; BF3 T-shaped; ClF3 trigonal planar
15. Which of the following best describes the shape and polarity of the carbon disulfide, CS2,
    molecule?
        a. bent and polar
        b. linear and non-polar
        c. pyramidal and polar
        d. bent and non-polar
        e. linear and polar
16. The shape of XeF4 is:
        a. tetrahedral.
        b. see-saw.
        c. square pyramidal.
        d. trigonal pyramidal.
        e. square planar.
17. Which of the following molecules or ions is nonplanar, i.e., has at least one atom that is
    not in the same plane as the others?
        a. BH3
        b. ClF3
        c. NF3
        d. SO3
        e. CO32-
18. On the basis of the VSEPR model, which of the following triatomic molecules has the
    smallest angle between the two bonds?
        a. CO2
        b. H2O
        c. SO2
        d. O3
        e. CH4
19. For the amino acid alanine, what is the bond angle about the indicated carbon atom?




        a. 109.5o
        b. 120o
        c. 180o
        d. 90o
        e. 360o
20. Identify the molecular geometry of formaldehyde, CH2O.
        a. linear
        b. trigonal planar
        c. bent
        d. tetrahedral
        e. trigonal bipyramidal
Answers

   1.    C
   2.    E
   3.    E
   4.    B
   5.    D
   6.    C
   7.    D
   8.    A
   9.    C
   10.   B
   11.   C
   12.   C
   13.   C
   14.   A
   15.   B
   16.   E
   17.   C
   18.   B
   19.   A
   20.   B

Intermolecular Forces, Liquids & Solids

   1. Based on intermolecular interactions, which of the following should have the highest
      boiling point?
          a. CH4
          b. CHCl3
          c. H2S
          d. CH3OH
   2. What is the typical range of strengths of hydrogen bonds?
          a. 5 - 25 kJ per mole of bonds
          b. 5 - 25 kJ per molecule
          c. 500 kJ per mole of bonds
          d. 1 - 2 kJ per mole of bonds
          e. less than all the above
   3. Hydrogen bonding is unimportant in
          a. ice formation
          b. the liquid properties of water
          c. DNA structure
          d. liquid CH4
          e. liquid HF
   4. Which one of the following statements is incorrect?
          a. Dispersion (London) forces are the weakest type of intermolecular interactions.
          b. The strong intermolecular attractions in H2O result from hydrogen bonding.
          c. The boiling point of H2S is lower than H2O.
          d. The boiling point of non-polar substances tends to decrease with increasing
              molecular weight.
   5. How many atoms per unit cell are there in each of the following cubic lattice types?
                 simple cubic    body-centered cubic     face-centered cubic

           (a)         8                   6                      12

           (b)         1                   2                      4

           (c)         1                   2                      6

           (d)         6                   8                      14


6. Which of the species below does not exhibit hydrogen bonding?
      a. C2H6
      b. NH3
      c. HF
      d. H2O
      e. C2H5OH
7. Which of the following phase diagrams is consistent with the sublimation of a solid at
   room temperature (22oC) and atmospheric pressure?




8. What type of attractive forces are being overcome when liquid oxygen boils at 90 K?
       a. ionic bonds
       b. dipole-dipole forces
       c. covalent bonds
       d. dispersion forces
       e. hydrogen bonds
9. What is the coordination number of each sphere in a three dimensional body-centered
   cubic array of equal-sized spheres?
       a. 4
       b. 6
       c. 8
       d. 12
       e. 16
10. Covalent bonds are the only type of bond or intermolecular forces in:
        a. KF(s).
        b. CO2(s).
        c. H2O(s).
        d. NH4NO2(s).
        e. C(diamond).
11. The density of silver is 10.5 g/cm3 and this metal crystallizes in the FCC structure.
    Assuming that nearest neighbor atoms are in contact, what is the atomic radius of Ag?
        a. 5.76 Angstroms
        b. 2.88 Angstroms
        c. 2.29 Angstroms
        d. 1.44 Angstroms
        e. 1.02 Angstroms
12. A white substance melts with some decomposition at 730oC. As a solid, it is a
    nonconductor of electricity but it dissolves in water to form a conducting solution. The
    white substance is:
        a. a covalent network solid.
        b. an ionic solid.
        c. a molecular solid.
        d. a metallic solid.
        e. solid Ar.
13. Which of the following elements has the highest boiling point?
        a. He
        b. F2
        c. Ne
        d. Br2
        e. Ar
14. Which of the following shows a hydrogen bonding interaction?
        a. NH3
        b. CH4
        c. BH3
        d. SiH4
        e. GeH4
15. Methanol, CH3OH (bp: 65oC), boils nearly 230o higher than methane, CH4 (bp: -164oC).
    What intermolecular forces are responsible for the higher boiling point of methanol?
        a. dispersion forces
        b. hydrogen bonds
        c. induced dipole-induced dipole
        d. ion-dipole
        e. dipole-induced dipole
16. The unit cell of a material has calcium ions at the corners, oxide ions in faces, and
    transition metal, M, in center. The empirical formula is:
        a. CaMO2
        b. CaMO3
        c. Ca4MO6
        d. Ca8MO3
        e. Ca8MO6
17. KCl has the same structure as NaCl. If the volume of the unit cell is 247.7 cubic
    Angstroms, what is the distance between adjacent K+ and Cl- centers?
        a. 1.24 Angstroms
        b. 2.48 Angstroms
        c. 3.14 Angstroms
        d. 3.63 Angstroms
        e. 6.28 Angstroms
18. Fe crystallizes in a body-centered cubic lattice. The density of iron is 7.86 g/cm3. The
    atomic radius of iron is: [1 Angstrom = 10-10 M = 10-8 cm]
        a. 1.24 Angstrom
        b. 2.48 Angstrom
        c. 0.62 Angstrom
        d. 2.02 Angstrom
        e. 0.717 Angstrom
19. The number of unit cells that share an atom represented by the filled circle in the diagram
    below is:




         a. 1
         b. 2
         c. 4
         d. 8
         e. 16
20. Aluminum crystallizes in a face-centered cubic lattice. Which of the following statements
    is false if r denotes radius of aluminum?




        a.   The unit cell contains 4 Al atoms.
        b.   The unit cell contains 1 octahedral hole.
        c.   The face diagonal has length 4r.
        d.   The volume occupied by Al in the unit cell is (16 r3/3).
        e.   The Al atoms are closest packed.
21. The sum of the first two ionization energies of Ca is 1735.2 kJ mol-1. Nevertheless, the
    Born-Haber cycle shows that CaCl2(s) is a stable ionic material because:
        a. the ionization of calcium is highly exothermic.
        b. the atomization (sublimation) of calcium is endothermic.
        c. chloride has an electron affinity so much greater than the ionization energies of
            calcium.
        d. the lattice energy more than compensates for the ionization energies.
        e. all of the above are true.
22. The figure depicts the unit cell for a compound containing atoms A (filled circles) and B
    (open circles). The empirical formula is:




        a.   AB
        b.   AB2
        c.   A2B
        d.   A6B
        e.   A12B2

    The next three questions refer to 4 liquids, all of which have the molecular formula
     C4H10O and which have the following boiling points: A (117.5oC); B (82.9oC); C
                                    (34.6oC); D (99.5oC).

23. The liquid likely to have the highest vapor pressure at 25oC is:
       a. A
       b. B
       c. C
       d. D
       e. All four substances would have the same vapor pressure since they have the same
            molecular weight.
24. The intermolecular attractive forces of these are likely to be ordered:
       a. A > D > B > C
       b. B > D > A > C
       c. C > B > D > A
       d. D > C > B > A
       e. none of the above
25. Given the structural isomers below, the one most likely to be liquid C is:
26. What pressure would be required to liquify (or condense) a sample of water vapor at
    500oC?




        a.  0.0060 atm
        b.  1.00 atm
        c.  218 atm
        d.  some pressure higher than 218 atm but which cannot be determined from the
            phase diagram
        e. no amount of pressure can bring about the change of H2O vapor to liquid at
            500oC
27. Drops of water and ethanol are placed on a warm stove, and the ethanol drop is seen to
    evaporate more rapidly. The graph below includes the vapor pressures of ethanol and
    water. Which curve corresponds to ethanol?
           a. A
           b. B
           c. C
           d. D
           e. none of the above
28.   Silver crystallizes with a face-centered cubic unit cell. The radius of a silver atom is
      0.144 nm. Calculate the density of solid silver.
           a. 25.0 g/cm3
           b. 20.0 g/cm3
           c. 15.6 g/cm3
           d. 10.6 g/cm3
           e. 5.3 g/cm3
29.   Which substance would have the strongest hydrogen bonding?
           a. CHCl3
           b. HBr
           c. H2O
           d. H2S
           e. H2Se
30.   Which of the following compounds feature intermolecular bonding in the liquid or solid
      state?
           a. argon
           b. diamond
           c. water
           d. sodium chloride
           e. none of these
31.   Which force makes the most important contribution to the lattice energy of solid argon?
           a. metallic bonding
           b. hydrogen bonding
           c. ionic bonding
           d. covalent bonding
           e. van der Waals forces
32.   The key bonding property that yields the characteristic properties of metals is:
           a.   -bonding.
           b. delocalized bonding caused by partly filled conduction bands.
           c. a filled conduction band.
           d. ionic bonding.
           e. van der Waals forces.
33. The increasing vapor pressure caused by heating a liquid is due to:
       a. increased intermolecular interactions.
       b. increasing potential energy of molecules.
       c. increasing kinetic energy of molecules.
       d. decreasing surface tension.
       e. weaker solvation.
34. The triple point is:
       a. the point in a phase diagram where the solid, liquid, and gas phases of a
            substance coexist at equilibrium.
       b. the point where all three phases are unstable.
       c. three places in a phase diagram where the solid, liquid and gas can coexist.
       d. a three-dimensional phase diagram.
       e. a rare play in baseball.
35. Decreasing the external pressure will:
       a. increase the vapor pressure of a liquid.
       b. markedly decrease the freezing point of a liquid.
       c. increase the boiling point of a liquid.
       d. decrease the boiling point of a liquid.
       e. weaken the intermolecular forces in a liquid.
36. Covalent crystals have:
       a. higher melting points than molecular crystals.
       b. lower melting points than molecular crystals.
       c. discrete molecules linked by van der Waals forces.
       d. hydrogen bonding.
       e. always excellent electrical conductivity.
37. Metals have:
       a. an unfilled conduction band.
       b. no conduction band.
       c. a partly filled conduction band.
       d. an energy gap between filled valence band and unfilled conduction band.
       e. only ionic bonding.
38. Which of the following statements is FALSE?
       a. Water boils at a lower temperature atop Mt. Everest than in Lafayette, IN.
       b. Ice has a lower density than liquid water.
       c. The vapor pressure of a liquid is lower than the external pressure at temperatures
            below its boiling point.
       d. A phase diagram is a pressure-temperature plot which outlines the P-T regions of
            stability of a molecule in its solid, liquid and gaseous forms.
       e. None of the above.
39. Choose the INCORRECT statement from the following:
       a. Hexagonal closest packed (hcp) and cubic close packed (ccp) structures have
            coordination numbers of 12 and 6, respectively.
       b. hcp and ccp structures involve ABABAB and ABCABCABC stacking,
            respectively.
       c. hcp and ccp structures involve the same net packing density.
       d. Metals can crystallize in either hcp or ccp structures, depending on the element.
       e. Some metals form body-centered cubic structures.
40. Which of the following statements about liquids is NOT true?
       a. liquids assume the shape of the container
       b. liquids assume the volume of the container
       c. liquids are virtually incompressible
             d. diffusion of liquids is slow
             e. liquids flow readily
   41.   What happens to molecules in a liquid when the liquid is heated and vapor starts to form?
             a. the intramolecular forces between liquid molecules are disrupted
             b. the intermolecular forces between liquid molecules are disrupted
             c. kinetic energy is removed from the system
             d. London forces become stronger
             e. surface tension increases, which causes beading up, then boiling
   42.   Which of the following has the lowest boiling point?
             a. F2
             b. Cl2
             c. Br2
             d. I2
   43.   Which of the following has the strongest intermolecular forces?
             a. O2
             b. Ar
             c. CH4
             d. HF
             e. HBr
   44.   Which of the following statements best explains why diamond (carbon) has a higher
         melting point than dry ice (CO2)?
             a. because carbon atoms in diamond are held together by a network of covalent
                 bonds
             b. because CO2 molecules are held together by dipole - dipole forces
             c. the electrostatic attractions in CO2 are not as strong as those in diamond (carbon)
             d. the dispersion forces in diamond are greater than in CO2
             e. all of the above



Answers

   1.    D
   2.    A
   3.    D
   4.    D
   5.    B
   6.    A
   7.    C
   8.    D
   9.    C
   10.   E
   11.   D
   12.   B
   13.   D
   14.   A
   15.   B
   16.   B
   17.   C
   18.   A
   19.   D
   20.   B
   21.   D
   22.   A
   23.   C
   24.   A
   25.   A
   26.   E
   27.   A
   28.   D
   29.   C
   30.   C
   31.   E
   32.   B
   33.   C
   34.   A
   35.   D
   36.   A
   37.   C
   38.   E
   39.   A
   40.   B
   41.   B
   42.   A
   43.   D
   44.   A



Aqueous Reactions & Solution Stoichiometry

   1. Which of the following pairs of molecules have the same oxidation number for carbon?
          a. CO and CO2
          b. CH4 and CCl4
          c. C6H12O6 and C(s)
          d. H2CO and COCl2
          e. Carbon always has an oxidation number of +4
   2. What mass of CuSO4.5H2O would you need to prepare 250.0 mL of a 0.250 M solution?
      [MW of CuSO4.5H2O = 249.5 g/mol]
          a. 2.5 g
          b. 15.6 g
          c. 25.0 g
          d. 62.5 g
          e. 15600 g
   3. Calculate the concentration of a solution formed when 15.0 mL of 6.00 M HCl are
      diluted with 25.0 mL of water.
          a. 0.150 M
          b. 0.240 M
          c. 2.25 M
          d. 3.60 M
       e. 6.00 M
4. Calculate the molarity of a sodium hydroxide solution if 10.42 mL of this solution are
   needed to neutralize 25.00 mL of 0.2043 M oxalic acid.

                      H2C2O4(aq) + 2NaOH(aq) --> Na2C2O4(aq) + 2H2O(l)

       a. 1.500 M
       b. 0.9803 M
       c. 0.4902 M
       d. 0.2500 M
       e. 0.1042 M
5. What is the oxidation number of Cr in potassium dichromate, K2Cr2O7?
       a. +2
       b. +4
       c. +6
       d. -4
       e. -6
6. What is the molarity of a solution made by having 90.0 g of acetic acid, CH3CO2H, in
   0.750 L of solution and given the atomic weights: C = 12.01 amu; H = 1.008 amu; O =
   16.00 amu?
       a. 0.076 M
       b. 1.12 M
       c. 5.20 M
       d. 0.90 M
       e. 2.00 M
7. How many grams of CaO are required for complete reaction with the HCl in 275 mL of a
   0.523 M HCl solution? The equation for the reaction is,

                                  CaO + 2HCl --> CaCl2 + H2O

    and the atomic weights are Ca = 40.08 amu; O = 16.00 amu.

       a. 806 g
       b. 403 g
       c. 8.06 g
       d. 4.03 g
       e. 0.523 g
8. What is the concentration of a NaOH solution made by dissolving 10.0 g NaOH in 50.0
   mL of water and adjusting the volume to 250.0 mL?
       a. 1.00 x 10-3 M
       b. 1.00 M
       c. 5.00 M
       d. 16.0 M
       e. 40.0 M
9. For the redox reaction:

                        Ca(s) + 2H2O(l) --> Ca2+(aq) + 2OH-(aq) + H2(g)

    which of the following statements is true?
        a. Ca is the oxidizing agent.
        b. H2 is reduced.
        c. Ca is reduced.
        d. H2O is the oxidizing agent.
        e. H2O is oxidized.
10. Sodium thiosulfate is used with silver bromide in film developing. The formula for
    sodium thiosulfate is Na2S2O3. What is the oxidation number for S, sulfur?
        a. -2
        b. +2
        c. -4
        d. +4
        e. +6
11. Calculate the molarity of vinegar (acetic acid) solution if you need 34.57 mL vinegar to
    neutralize (use up) 25.19 mL of 0.1025 M NaOH.

                CH3COOH(aq) + NaOH(aq) --> CH3COO-(aq) + Na+(aq) + H2O

        a. 0.07469 M
        b. 0.07287 M
        c. 0.03457 M
        d. 0.02519 M
        e. 0.1025 M
12. Students were trying to determine the identity of a substance dissolved in water. The
    solution was odorless and colorless. After they had narrowed the list of possible
    substances to five compounds they added solutions of Na2S, KOH, and HCl to individual
    samples of the unknown and recorded the results as shown in the table.

                       Possibilities: AgNO3 ; Na2CO3 ; Na2S ; NaCl ; NH3

               Table 1: Observations of Unknown with Test Reagents
                       with Na2S           with KOH(aq)            with HCl(aq)
                   colorless solution;    colorless solution;   colorless solution;
      unknown        no precipitate;        no precipitate;       no precipitate;
                      no bubbling            no bubbling           no bubbling

    The dissolved "unknown" substance in the solution is:

        a. AgNO3
        b. Na2CO3
        c. Na2S
        d. NaCl
        e. NH3
13. Students were trying to determine the identity of a substance dissolved in water. The
    solution was odorless and colorless. After they had narrowed the list of possible
    substances to five compounds [AgNO3, NaCl, HCl, Na2CO3, BaCl2] they added solutions
    of AgNO3, NaCl and Na2S to separate samples of the unknown and recorded the results
    as shown in Table I:
                 Table I: Observations of Unknown with Test Reagents
                      with AgNO3(aq)          with NaCl(aq)         with Na2S(aq)
                      colorless solution;
                                             white precipitate;    black precipitate;
        unknown         no precipitate;
                                               no bubbling            no bubbling
                         no bubbling

14. The substance dissolved in the "unknown" solution is:
       a. AgNO3
       b. NaCl
       c. HCl
       d. Na2CO3
       e. BaCl2
15. Oxalic acid, H2C2O4, reacts with the chromate ion in acidic solution as follows:

             3H2C2O4(aq) + 2CrO42-(aq) + 10H+(aq) --> 6CO2(g) + 2Cr3+(aq) + 8H2O(l)

      What is the molarity of the oxalic acid solution if 10.0 mL of this solution consumes 50.0
      mL of 0.0350 M CrO42-?

           a. 0.263 M
           b. 0.175 M
           c. 0.00700 M
           d. 0.0350 M
           e. 0.0105 M
16.   You carried out an acid-base titration. You obtained 2.50 x 102 mL of 0.107 M HCl. This
      required 17.00 mL of KOH solution for exact neutralization. What is the molarity of the
      KOH solution?
           a. 0.107 M
           b. 0.168 M
           c. 1.57 M
           d. 2.50 M
           e. 2.65 M
17.   What volume of 0.500 M glucose, C6H12O6, contains 3.01 x 1022 molecules of glucose?
           a. 5.00 x 101 mL
           b. 1.00 x 102 mL
           c. 5.00 x 102 mL
           d. 1.00 x 103 mL
           e. none of these
18.   What is the molarity of chloride ion in 0.123 M solution of BaCl2?
           a. 0.0615 M
           b. 0.123 M
           c. 0.246 M
           d. 1.369 M
           e. 1.23 M
19.   You have a job in the General Chemistry Prep Laboratory. Your first task is to prepare
      five 1000-mL volumetric flasks, each containing 1.000 L of 0.100 M HCl. You will do
      this by adding a measured volume of concentrated HCl, which is 11.6 M and making up
      the rest of the volume by filling the flasks with H2O up to the mark. The volume of
      concentrated HCl you will add to each flask is:
          a. 0.862 mL
          b. 8.62 mL
          c. 86.2 mL
          d. 1.16 mL
          e. 11.6 mL
20.   An experiment calls for 200 mL of 2.0 M HCl. If you had a 9.0 M stock solution of HCl
      on hand, how many mL of this solution would be required?
          a. 400 mL
          b. 125 mL
          c. 44 mL
          d. 14 mL
          e. 9.0 mL
21.   All of the following are soluble compounds, EXCEPT:
          a. (NH4)2CO3
          b. K3PO4
          c. Sr(OH)2
          d. CsNO3
          e. Mg(OH)2
22.   Which of the following does not form a strong electrolyte?
          a. Ba(OH)2
          b. H2SO4
          c. NH3
          d. NaCl
          e. Sr(NO3)2
23.   The following titration reaction was carried out:

                                2HCl + Ba(OH)2 --> BaCl2 + 2H2O

      If 22.0 mL of 2.5 M HCl was used to neutralize 50.0 mL of a Ba(OH)2 solution, what was
      the concentration of the base?

       a. 2.2 M
       b. 1.5 M
       c. 1.1 M
       d. 0.85 M
       e. 0.55 M
24. Which of the species in the following complete ionic equation are spectator ions?

                        2KCl(aq) + Pb(NO3)2(aq) --> PbCl2(s) + 2KNO3(aq)

       a. K+, Pb2+
       b. Pb2+, Cl-
       c. NO3-
       d. Cl-, NO3-
       e. K+, NO3-
25. How many electrons are being transferred in the following redox reaction?

                             Cu(s) + ZnCl2(aq) --> Zn(s) + CuCl2(aq)

         a. 1
         b. 2
         c. 3
         d. 4
         e. it cannot be determined
26. Using the Activity Series below, which of the following redox reactions will NOT react
    to form product?
         a. Al(s) + NiCl2(aq) -->
         b. Mn(s) + HBr(aq) -->
         c. Ag(s) + AuCl3(aq) -->
         d. PtBr2(aq) + H2(g) -->
         e. Hg(l) + HCl(aq) -->




27. Which of the following reactions is NOT a redox reaction?
       a. 2Cu(s) + O2(g) --> 2CuO(s)
       b. Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)
       c. Zn(s) + FeBr2(aq) --> Fe(s) + ZnBr2(aq)
       d. CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g)
       e. all are redox reactions
28. Which of the following is NOT a common driving force in metathesis reactions?
       a. precipitation
       b. the transfer of electrons
       c. evolution of a gas
       d. formation of a weak or nonelectrolyte
       e. none of these are driving forces
29. The volume of a 3.72 M Na3PO4 solution needed to prepare 2.50 x 102 mL of a 1.43 M
    Na+ solution is:
       a. 24.0 mL
       b. 32.0 mL
              c. 48.1 mL
              d. 96.1 mL
              e. Cannot be answered because this is an impossible solution to prepare.
    30. The oxidation numbers for all the elements in each compound are correct EXCEPT for:
              a. Fe2(CrO4)3 ; Fe: +3; Cr: +6; O: -2
              b. Mn(ClO3)2 ; Mn: +2; Cl: +5; O: -2
              c. HgCr2O7 ; Hg: +2; Cr: +6; O: -2
              d. HClO4 ; H: +1; Cl: +7: O: -2
              e. Co3(PO4)2 ; Co: +2; P: +4; O: -2
    31. As a new technician in a quality control lab you have just been assigned to prepare 0.100
        M NH3 solutions in each of five, separate 1000-mL volumetric flasks. You will do this by
        adding a measured volume of 14.8 M NH3 to each and then filling the flasks with H2O up
        to the mark on the neck of the flask. The volume of 14.8 M NH3 that you will add to each
        flask is:
              a. 0.676 mL
              b. 6.76 mL
              c. 67.6 mL
              d. 1.48 mL
              e. 14.8 mL
    32. After 111 mL of 0.111 M NaOH and 111 mL of 0.111 M H2SO4 are mixed, assuming
        that the volumes are additive, the concentration of H+ is:
              a. 0.0555 M
              b. 0.111 M
              c. 0.222 M
              d. 0.333 M
              e. none of these
    33. You are assigned the task of standardizing a NaOH solution that was prepared by the
        technician who quit his job the day before you started work as an intern. You decide to
        use the titration technique and then make a list of measurements and information that you
        will need to accomplish the assignment. Which of the following will you need to
        complete the calculations for the assignment?
            i.    balanced chemical equation for reaction between acid and base
           ii.    mass and chemical formula of a known acid
          iii.    mass and MW of NaOH the technician used to prepare the solution
          iv.     total volume of NaOH solution that the technician prepared
           v.     volume of NaOH solution needed to turn the solution pink
                      a. i, ii and v.
                      b. i, iii, and iv
                      c. ii and v.
                      d. ii, iii, and iv.
                      e. all the above would be needed to determine the concentration of NaOH
34. Which of the following species is considered insoluble in pure H2O?
        a. KCl
        b. (NH4)2S
        c. NH4Br
        d. SrSO4
        e. All of the above are considered soluble.
35. Given a solution containing both silver acetate and copper(II) acetate you wish to add another
    solution such that one of the two above cations will precipitate, while the other will remain in
    solution. Of the aqueous solutions below, which will do what you wish?
              a. KCl
               b. KNO3
               c. KOH
               d. K2S
               e. none of these
36.   Which of the following species will NOT convert Sn2+ to Sn metal?
               a. Ca
               b. Mn
               c. Co
               d. Pb
               e. All of these will convert Sn2+ to Sn.
37.   How many moles of NaOH are in 22.0 mL of 0.150 M NaOH?
               a. 0.00148
               b. 0.00221
               c. 0.00330
               d. 1.48
               e. 3.30
38.   Which of the following sets is a weak acid and weak base, respectively?
               a. HClO4, NH3
               b. HF, Ca(OH)2
               c. HCl, LiOH
               d. H2CO3, NH3
               e. HBr, NaOH
39.   What is the concentration of an HCl solution if 22.0 mL required 43.2 mL of a 0.100 M
      NaOH solution to reach the endpoint?
               a. 0.196 M
               b. 5.09 M
               c. 0.00432 M
               d. 0.000509 M
               e. 0.100 M
40.   All of the following are strong electrolytes in aqueous solution except:
               a. H2CO3
               b. H2SO4
               c. KOH
               d. NaCl
               e. HCl
41.   An antacid tablet containing 0.50 g NaHCO3 (molar mass = 84.01 g) is dissolved in water.
      The total volume of solution is 250 mL. What is the molarity of this NaHCO3 solution?
               a. 0.024 M
               b. 4.1 M
               c. 2.22 x 10-4 M
               d. 0.0060 M
               e. 0.0041M
42.   Which of the following ionic compounds is insoluble in water?
               a. NH4Cl
               b. AgNO3
               c. PbSO4
               d. KI
               e. Na2S
43.   In accordance with solubility rules, which of the following is true when solutions containing
      Pb(NO3)2(aq) and KI(aq) are mixed?
               a. KNO3 will precipitate; Pb2+ and I- are spectator ions.
          b. No precipitate will form.
          c. Pb(NO3)2 will precipitate; K+ and I- are spectator ions.
          d. PbI2 will precipitate; K+ and NO3- are spectator ions.
          e. Pb2+ and I- are spectator ions and PbI2 will precipitate.
44. How many moles of NH3 are produced from 5.0 moles of H2 with excess N2?

                                             N2 + 3H2 --> 2NH3

              a. 2.0
              b. 3.0
              c. 5.0
              d. 3.3
              e. 7.0
45.   Identify the major ions present in an aqueous solution of NaOH.
              a. Na2+, O- , H-
              b. Na+, OH-
              c. NaO- , H+
              d. Na+, O2- , H+
              e. Na- , OH+
46.   Which of the following is not a characteristic of an acid?
              a. a sour taste.
              b. turns litmus paper red.
              c. feels slippery.
              d. reacts with most metals to release H2.
47.   40.0 mL of a HCl solution with concentration of 0.60 M is to be diluted to a concentration of
      0.10 M. What would be the final volume after dilution?
              a. 6.67 mL
              b. 667 mL
              c. 240 mL
              d. 60.0 mL
              e. 500 mL
48.   The distinguishing characteristic of all electrolyte solutions is that they:
              a. contain molecules.
              b. conduct electricity.
              c. react with other solutions.
              d. always contain acids.
              e. conduct heat.
49.   Using the following activity series, which of the following reactions will take place?
             a. 2Na + 2H+ --> 2Na+ + H2
             b. Cu + 2H+ --> Cu2+ + H2
             c. Ni2+ + Cu --> Ni + Cu2+
             d. 3Ag+ + Au --> 3Ag + Au3+
             e. Cr3+ + 3Ag --> Cr + 3Ag+
50. Which of the following is insoluble?
             a. AgI
             b. Na2SO4
             c. KNO3
             d. NaOH
             e. CH3COOH
51. When ammonia (NH3) is added to water, what are the products in the reaction?
             a. H+, NH4+
             b. OH-, NH4+
             c. H2O, NH4OH
             d. H+, OH-
             e. no reaction occurs
52. In the following reaction, which are considered spectator ions?

                             2HCl(aq) + Na2S(aq) --> H2S(g) + 2NaCl(aq)

            a. H+, S2-
            b. H+, Cl-
            c. Na+, Cl-
            d. S2-, Cl-
            e. Na+, H+
53. Zn(OH)2 solid (molecular mass = 99.41 amu) is added to 0.400 L of 0.550 M HBr. The
    resultant solution which is acidic, requires 165 mL of 0.500 M NaOH for neutralization. The
    mass (in mg) of Zn(OH)2 that was originally added was numerically:
            a. 6.83 mg
            b. 82.5 mg
            c. 138 mg
            d. 6830 mg
            e. None of the above are close to the correct answer.
54. Which unbalanced oxidation-reduction reaction is possible?
             a. Al3+ + Fe2+ --> Al + Fe3+
             b. Al3+ + Fe2+ --> Al + Fe
             c. Al + Fe2+ --> Al3+ + Fe3+
             d. Al + Fe --> Al3+ + Fe3+
             e. Al3+ + Fe3+ --> Al + Fe
55. After 111 mL of 0.111 M HNO3 and 111 mL of 0.111 M Ca(OH)2 are mixed, assuming the
    volumes are additive, the concentration of OH- ion is:
             a. 0 M (sufficient acid has been added to neutralize the base).
             b. 0.0555 M
             c. 0.111 M
             d. 0.222 M
             e. 0.333 M
56. Which of the following elements will convert Cr3+ to Cr metal?
             a. Mg
             b. Co
             c. Pb
             d. Ag
             e. None of these will convert Cr3+ to Cr.
57. How many mL of 0.627 M NaOH will be required to prepare 100.0 mL of 0.0725 M NaOH?
             a. 5.78
             b. 11.6
             c. 23.1
             d. 46.3
             e. None of these
58. Considering what is a strong, weak or non-electrolyte, which of the rows in the following
    table is completely correct?


                    CuSO4     KOH      C2H5OH      HC2H3O2      HNO3      C12H22O11

              (a)   strong    strong      non        strong      weak        non

              (b)   strong    strong     strong       weak      strong       non

              (c)    weak     strong     weak         weak      strong       non

              (d)   strong    strong      non         weak      strong       non

              (e)   strong    weak        non         weak      strong      weak


59. Which of the following is(are) a driving force(s) for a chemical reaction to occur in aqueous
    solution?
            a. A gas forms.
            b. A precipitate forms.
            c. An ion-dipole interaction forms.
            d. A weak acid or base forms.
            e. All of the above serve to drive the reaction.
60. When 25.0 mL of 0.400 M H2SO4 and 50.0 mL of 0.850 M H2SO4 are mixed, what is the
    molarity of sulfuric acid in the final solution?
           a. 0.350 M H2SO4
           b. 0.700 M H2SO4
           c. 3.50 M H2SO4
           d. 7.00 M H2SO4
           e. 10.0 M H2SO4
61. Almost all sulfides are water insoluble. Exceptions include:
           a. FeS
           b. CuS
           c. CdS
           d. SrS
           e. HgS
62. What are the spectator ions in the following reaction/equation?

                        Pb(NO3)2(aq) + Na2SO4(aq) --> PbSO4(s) + 2NaNO3(aq)

            a. Pb2+, SO42-
            b. Pb2+, NO3-
            c. Na+, NO3-
            d. Na+, SO42-
            e. Na+
63. Identify which one of the following constitutes an aqueous 1.0 M NaCl solution:
            a. 1.0 L of aqueous solution containing 100 g NaCl
            b. 500 mL of aqueous solution containing 58.44 g NaCl
            c. an aqueous solution containing 5.844 mg NaCl per 1 mL
            d. 5.00 L of aqueous solution containing 292.2 g NaCl
            e. 58.44 g NaCl added to exactly 1 L of pure water

          The next two questions refer to a solution made by dissolving 0.5103 g of a solid
         diprotic acid in enough pure water to make 50.00 mL of solution; 10.00 mL of this
                 solution is completely neutralized by 18.75 mL of 0.0725 M NaOH.

64. The molarity of the acid solution is numerically:
             a. 0.0340
             b. 0.0680
             c. 0.0725
             d. 1.36
             e. none of the above
65. The molecular mass of the acid (in amu) is numerically:
             a. 7.50 x 101
             b. 1.50 x 102
             c. 3.00 x 102
             d. 7.50 x 102
             e. none of these
66. In the lab 7.58 g of barium nitrate Ba(NO3)2 (molar mass = 261.36) is dissolved in enough
    water to form 0.850 L of solution. A 0.100 L sample is withdrawn from this stock and titrated
    with a 0.051 M solution of K2SO4. What volume of K2SO4 solution is required to preciptate
    all the Ba2+ as BaSO4?
             a. 0.033 L
             b. 0.067 L
             c. 0.134 L
             d. 0.167 L
             e. 0.240 L
67. Which of the following describes what occurs between Zn(s) and Mn2+ in aqueous solution?
             a. Zn is a reducing agent.
             b. Zn is oxidized.
             c. Mn2+ is an oxidizing agent.
             d. All of the above are true.
             e. No reaction occurs.
68. Which of the following will NOT reduce Fe2+ to Fe?
             a. Na
             b. Pb
             c. Zn
             d. Cr
             e. All of these will reduce Fe2+ to Fe.
69. In the following balanced equation,

                  6I-(aq) + 14H3O+(aq) + Cr2O72-(aq) --> 2Cr3+(aq) + 21H2O(l) + 3I2(s)

        the reducing agent (that is, the substance oxidized) is:

             a. H3O+
             b. H+
             c. Cr2O72-
             d. I-
             e. H2O
70. In which of the following reactions does the lead reactant species act as a reducing agent?
             a. Pb + 1/2O2 --> PbO
             b. PbO + C --> 2Pb + CO
             c. PbS + 3/2O2 --> PbO + SO2
             d. 2Al + 3PbO --> Al2O3 + 3Pb
             e. none of the above
71. In a lecture demonstration, magnesium metal was given sufficient energy to burn in air. The
    metal continued to burn even after it was covered with dry ice, solid CO2:

                                   2Mg(s) + CO2(s) --> 2MgO(s) + C(s)

        In the reaction of Mg with CO2:

             a. Carbon is oxidized, oxygen is reduced.
             b. Oxygen is oxidized, carbon is reduced.
             c. Oxygen is oxidized, Mg is reduced.
             d. Mg is oxidized, oxygen is reduced.
             e. Mg is oxidized, carbon is reduced.
72. In a class demonstration we titrated 1.00 x 102 mL of 0.100 M of Ba(OH)2 with 1.00 M
    H2SO4. The balanced equation is:

                            Ba(OH)2(aq) + H2SO4(aq) --> BaSO4(s) + 2H2O(l)

        What volume of the H2SO4 solution did we add to neutralize the Ba(OH)2? Remember
        that we used conductivity (light bulb) as an indicator.
              a. 5 mL
              b. 10 mL
              c. 20 mL
              d. 100 mL
              e. 200 mL
73.   What is the oxidation number of phosphorus in K3PO3?
              a. -6
              b. +1
              c. -3
              d. +3
              e. +6
74.   What is the oxidation number for iodine in KIO4?
              a. +7
              b. +3
              c. 0
              d. -3
              e. -7
75.   Calculate the molarity of an ammonia solution that contains 252.9 g of NH3 in 2.52 L of
      solution.
              a. 1.00 M
              b. 5.89 M
              c. 14.8 M
              d. 25.2 M
              e. 100.0 M
76.   What is the molarity of CH3OH in a solution prepared by dissolving 11.7 g of CH3OH in
      enough water to make a 250. mL solution?
              a. 11.9 M
              b. 1.59 x 10-3 M
              c. 0.0841 M
              d. 1.46 M
              e. 46.8 M
77.   Which of the following is a weak acid?
              a. HNO3
              b. HCl
              c. HI
              d. HClO4
              e. H2SO3
78.   What are the spectator ions in the reaction between KOH and HNO3?

                                         KOH(aq) + HNO3(aq) -->

           a. K+ and H+
           b. H+ and OH-
           c. K+ and NO3-
           d. H+ and NO3-
           e. all ions are spectator ions because there is no reaction
79. Which of the following is an insoluble compound?
           a. Na2CO3
           b. AgNO3
           c. FeSO4
           d. Na2S
            e. SrCO3
80. What is the concentration of an HI solution if 75.0 mL of the acid required 35.21 mL of
    0.1894 M KOH to reach the endpoint in the titration?
            a. 0.2668 M
            b. 0.8003 M
            c. 0.08892 M
            d. 0.1345 M



Answers

    1.    C
    2.    B
    3.    C
    4.    B
    5.    C
    6.    E
    7.    D
    8.    B
    9.    D
    10.   B
    11.   A
    12.   D
    13.   A
    14.   A
    15.   C
    16.   B
    17.   C
    18.   B
    19.   C
    20.   E
    21.   C
    22.   E
    23.   E
    24.   B
    25.   E
    26.   E
    27.   B
    28.   B
    29.   E
    30.   B
    31.   A
    32.   A
    33.   D
    34.   A
    35.   D
    36.   C
    37.   D
    38.   A
39.   A
40.   A
41.   C
42.   D
43.   D
44.   B
45.   C
46.   C
47.   B
48.   A
49.   A
50.   B
51.   C
52.   D
53.   A
54.   B
55.   A
56.   B
57.   D
58.   E
59.   B
60.   D
61.   C
62.   D
63.   B
64.   B
65.   B
66.   E
67.   B
68.   D
69.   A
70.   E
71.   B
72.   D
73.   A
74.   B
75.   D
76.   E
77.   C
78.   E
79.   C




          Questions from Previous Chemistry 115 Exams

                         Stoichiometry
1. Using the periodic table, predict what the proper empirical formula will be when
   magnesium reacts with fluorine to form an ionic solid.
       a. MgF2
       b. MgF
       c. Mg2F
       d. Mg2F2
       e. it cannot be determined.
2. How many grams does 4.00 moles of H2O weigh?
       a. 4.00 g
       b. 4.50 g
       c. 18.0 g
       d. 72.0 g
       e. 144.0 g
3. How many H2O molecules are there in a snow flake that weighs 4.0 x 10-4 g?
       a. 1.3 x 1019
       b. 2.4 x 1020
       c. 2.2 x 10-5
       d. 6.02 x 1023
       e. it cannot be determined
4. If you take a 0.100 g dose of Vitamin C, C6H8O6, how many moles is this?
       a. 0.100 mol
       b. 5.68 x 10-4 mol
       c. 17.61 mol
       d. 2.01 mol
       e. 6.84 x 10-2 mol
5. For the following reaction, what is the stoichiometric coefficient for water that balances
   the reaction?

                                 N2O5 + ___ H2O --> ___ HNO3

        a. 1
        b. 2
        c. 3
        d. 4
        e. 5
6. For the following combustion reaction, what is the stoichiometric coefficient for oxygen
   that balances the reaction?

                              C3H8 + __ O2 --> ___ H2O + ___ CO2

      a. 1
      b. 2
      c. 3
      d. 4
      e. 5
7. The following reaction: 2Mg + O2 --> 2MgO can be classified as a
      a. Combustion reaction
      b. Acid-base reaction
      c. Decomposition reaction
      d. Combination reaction
      e. None of these
8. What is the percent composition of phosphorous in P4O10?
      a. 10.9%
      b. 60.0%
      c. 43.6%
      d. 36.4%
      e. 100%
9. Consider the following (balanced) combustion reaction. If 16 g of CH4 are consumed,
   what is the amount of H2O produced, in g?

                                   CH4 + 2O2 --> CO2 + 2H2O

               MW CH4 = 16 g/mol                    MW O2 = 32 g/mol
               MW CO2 = 44 g/mol                   MW H2O = 18 g/mol

         a. 64 g
         b. 32 g
         c. 18 g
         d. 36 g
         e. 44 g
10. What is the average mass of 10 aluminum atoms?
         a. 26.981 amu
         b. 1.624 x 10-26 g
         c. 269.81 g
         d. 4.481 x 10-22 g
         e. 1.661 x 10-24 g
11. The common name for acetic acid is vinegar. The chemical formula is CH3CO2H. How
    many atoms of hydrogen are present in 35.00 moles of vinegar?
         a. 8.431 x 1025
         b. 2.108 x 1025
         c. 1.400 x 102
         d. 1.744 x 10-22
         e. 2.401 x 1024
12. In the balanced equation for the reaction:

                                NH3(g) + O2(g) --> NO(g) + H2O(g)

   The coefficient for O2 is:

      a. 1
      b. 3
      c. 5
      d. 8
      e. 10
13. What is the empirical formula of a compound that contains 30.43% N and 69.57% O?
      a. N2O
      b. NO
      c. NO2
      d. N2O3
        e. N2O4
14. Solid lithium hydroxide is used by NASA to remove (scrub) carbon dioxide from the
    spacecraft by reacting with the carbon dioxide to form solid lithium carbonate and liquid
    water. The balanced equation is:

                           2LiOH(s) + CO2(g) --> Li2CO3(s) + H2O(l)

    What mass of lithium carbonate will be formed by reacting 3.80 kg of lithium hydroxide
    with excess carbon dioxide?

        a. 3.80 kg
        b. 5.86 kg
        c. 11.7 kg
        d. 280 kg
        e. not enough information
15. Apatite is a mineral found in tooth enamel. When fluoride toothpastes are used, the
    mineral is converted to fluoroapatite, which is much harder and therfore more resistant to
    tooth decay. The formula for fluoroapatite is Ca5(PO4)3F. What is the molecular weight?
        a. 106.1 g/mol
        b. 200.4 g/mol
        c. 314.4. g/mol
        d. 424.3 g/mol
        e. 504.3 g/mol
16. Which is the limiting reagent when 10.0 g of H2 and 10.0 g of Cl2 react according to the
    reaction:

                                   H2(g) + Cl2(g) --> 2HCl(g)

        a. H2
        b. Cl2
        c. HCl
        d. Not enough information.
        e. None of the above. They are present in equal amounts.
17. How many chlorine atoms are contained in 18.29 g of chlorine given that the atomic
    weight of chlorine is 35.453 amu?
        a. 2.767 x 1023
        b. 1.244 x 1024
        c. 8.172 x 10-25
        d. 7.776 x 1015
        e. 3.107 x 1023
18. What is the mass in grams of Zirconium (Zr) in 0.3384 mol of the mineral zircon, ZrSiO4,
    given the atomic weights: Zr = 91.22 amu; Si = 28.09 amu; O = 16.00 amu?
        a. 30.87 g
        b. 21.66 g
        c. 9.36 g
        d. 273 g
        e. 97.6 g
19. What is the % by weight of carbon in ascorbic acid, C6H8O6, also known as Vitamin C,
    given the atomic weights: C = 12.01 amu; H = 1.008 amu; O = 16.00 amu?
        a. 40.9%
         b. 4.58%
         c. 54.5%
         d. 30.0%
         e. 12.0%
20. What is the empirical formula of a compound that contains 87.5% N and 12.5% H by
    weight, given the atomic weights: N = 14.01 g; H = 1.008 g?
         a. N2H4
         b. NH3
         c. NH2
         d. N2H6
         e. N2H
21. What is the mass of AlBr3 in grams produced by the reaction of 1.5 mol of HBr according
    to the following equation:

                                  2Al + 6HBr --> 2AlBr3 + 3H2

    and given the atomic weights: Al = 26.98 amu; Br = 79.90 amu; H = 1.008 amu?

       a. 520 g
       b. 260 g
       c. 130 g
       d. 65.0 g
       e. 79.9 g
22. Which is the limiting reagent when 62.0 g of P4 and 128 g of S8 react according to:

                                      4P4 + 5S8 --> 4P4S10

    and given the atomic weights: P = 31.0 amu; S = 32.0 amu?

        a. P4
        b. S8
        c. not enough information
        d. neither P4 nor S8
        e. both P4 and S8
23. Magnesium metal burns in oxygen to form magnesium oxide, MgO. The theoretical yield
    of magnesium oxide from a reaction mixture containing 1.204 x 1024 Mg atoms and 25.0
    g oxygen gas is: [AW: Mg = 24.31; O = 16.00]
        a. 0.391 mol
        b. 0.781 mol
        c. 1.56 mol
        d. 2.00 mol
        e. 2.78 mol
24. What is the coefficient of O2 appearing in the following equation when it is balanced with
    smallest whole numbers?

                                  C6H12O6 + O2 --> CO2 + H2O

        a. 1
        b. 2
        c. 6
         d. 9
         e. 18
25. A reaction occurs between sodium carbonate and hydrochloric acid producing sodium
    chloride, carbon dioxide and water. The correct coefficients for the balanced equation in
    the order of the substances given is:
         a. 3, 6, 6, 3, 4
         b. 8, 6, 5, 10, 5
         c. 5, 10, 10, 5, 5
         d. 1, 2, 2, 1, 1
         e. none of these
26. Apatite is a mineral that is found in tooth enamel. When fluoride toothpastes are used,
    this mineral is converted to fluoroapatite, which is more resistant to tooth decay. Keith is
    very dilligent at brushing his teeth, and as a result has 5.00 g of fluroapatite, Ca5(PO4)3F
    in his teeth. What is the mass of oxygen in this amount of fluoroapatite? [Ca5(PO4)3F =
    504.5 g/mol]
         a. 0.635 g
         b. 1.11 g
         c. 1.90 g
         d. 6.40 g
         e. 540.45 g
27. Calculate the amount of phosphine, PH3, that can be prepared when 10.0 g of calcium
    phosphide, Ca3P2 reacts with excess water.

                         Ca3P2(s) + 6H2O(l) --> 3Ca(OH)2(aq) + 2PH3(g)

        a. Not enough information given.
        b. 0.110 g
        c. 1.86 g
        d. 3.73 g
        e. 20.0 g
28. Scott reacts 10.0 g of hydrogen and 10.0 g of chlorine (in a safety hood, while wearing
    safety goggles). What is the mass of the hydrochloric acid that is produced?

                                    H2(g) + Cl2(g) --> 2HCl(g)

        a. 10 g
        b. 10.3 g
        c. 20.0 g
        d. 20.6 g
        e. 183 g
29. A mole of sodium nitrate (NaNO3):
        a. contains 6.02 x 1023 sodium nitrate units.
        b. contains 6.02 x 1023 nitrogen atoms.
        c. weighs 85.0 g.
        d. contains 5 moles of atoms.
        e. All of the above are true.
30. The first substance to act as a superconductor at a temperature above 77 K has the
    molecular formula YBa2Cu3O7. Calculate the percent composition by mass of the element
    Ba in this material.
        a. 16.8%
       b. 28.6%
       c. 41.2%
       d. 13.3%
       e. 17.6%
31. An unknown compound is made up of C, H, N and O. A 2.402-g sample of this
    compound contains 1.121 g of N, 0.161 g H, 0.480 g C, and an unspecified amount of
    oxygen. What is the empirical formula of the unknown compound?
       a. CH4NO
       b. CH4N2O
       c. CH4N2O2
       d. C2H8NO
       e. C2H8N4O2
32. How many hydrogen atoms are there in 1.0 x 101 g of glucose, C6H12O6?
       a. 12
       b. 12 x 1023
       c. 4.0 x 1023
       d. 8.0 x 1023
       e. 0.067
33. How many moles of Cr(s) are needed to balance the following equation?

                                    Cr(s) + S8(s) --> Cr2S3(s)

        a. 2
        b. 4
        c. 6
        d. 8
        e. 16
34. The amount of copper in a certain alloy is determined by reacting the copper with sulfuric
    acid,

                     Cu(s) + 2H2SO4(aq) --> CuSO4(aq) + SO2(g) + 2H2O(l)

    and then precipitating solid CuI with KI solution,

                   2CuSO4(aq) + 5KI(aq) --> 2CuI(s) + KI3(aq) + 2K2SO4(aq)

    What mass of copper was present if 4.86 g of CuI was recovered?

        a. 4.86 g
        b. 3.24 g
        c. 2.43 g
        d. 1.62 g
        e. 0.811 g
35. A mixture of 12.2 g of potassium and 22.2 g of bromine, Br2, was heated until the
    reaction was completed. What mass of KBr is formed?
        a. 119 grams
        b. 22.2 grams
        c. 27.8 grams
        d. 33.1 grams
        e. 30.0 grams
36. When 12.0 g of hydrogen reacts with 12.0 g of chlorine,

                                     H2(g) + Cl2(g) --> 2HCl(g)

      5.53 g of hydrogen chloride are recovered. The percent yield of HCl is:

           a. 1.27%
           b. 2.55%
           c. 45.0%
           d. 89.9%
           e. 100%
37.   After looking at this exam, you take a deep breath and inhale 1.16 x 1022 molecules of air,
      which is a mixture of several gases. Assume that the molar mass of air is 29.0 g/mol.
      What is the mass of air that you just inhaled?
           a. 10.0 grams
           b. 1.11 grams
           c. 0.558 grams
           d. 0.501 grams
           e. 0.279 grams
38.   If the average mass of a single oxygen atom is 26.58 x 10-24 g, what is the mass in grams
      of 6.02 x 1023 oxygen atoms?
           a. 4.0 g
           b. 8.0 g
           c. 16.0 g
           d. 32.0 g
           e. 64.0 g
39.   When the chemical equation describing the complete combustion of benzene, C6H6, with
      oxygen to form CO2 and water is balanced, one can determine that the number of moles
      of oxygen consumed per mole of benzene is:
           a. 15
           b. 7.5
           c. 3
           d. 2
           e. the equation cannot be balanced for 1 mole C6H6
40.   Iron(II) sulfate, FeSO4, is prescribed for the treatment of anemia. How many moles of
      FeSO4 are present in a standard 300 mg tablet?
           a. 1.57 x 10-5 mol
           b. 3.57 x 10-4 mol
           c. 2.97 x 10-3 mol
           d. 1.97 x 10-3 mol
           e. 1.97 mol
41.   A hydrocarbon molecule consists of 90.0% C and 10.0% H by weight. Its molecular
      weight is 120 amu. How many atoms (carbon and hydrogen together) are there in this
      molecule?
           a. 19
           b. 20
           c. 21
           d. 22
           e. 23
       The next four questions refer to vanillin, C8H8O3 (MW = 152.14). The equation
                    representing the complete combustion of vanillin is:

                         2C8H8O3(l) + 17O2(g) --> 16CO2(g) + 8H2O(g)

42. The number of carbon atoms in 1.3 mole of vanillin is:
         a. 8 atoms.
         b. 16 atoms.
         c. 7.8 x 1023 atoms.
         d. 6.3 x 1024 atoms.
         e. 1.3 x 1025 atoms.
43. The percent by mass of oxygen in vanillin is:
         a. 63.16%.
         b. 31.55%.
         c. 15.79%.
         d. 5.30%
         e. none of the above
44. The theoretical yield of CO2 from a reaction mixture containing 45.6 g of vanillin and
    73.2 g O2 is:
         a. 63.2 g.
         b. 94.8 g.
         c. 1.00 x 102 g.
         d. 118.6 g
         e. none of these
45. An unknown amount of vanillin was burned in a flask with excess O2. The 67.3 g of CO2
    that was recovered is 76.9% of the theoretical yield. The original sample of vanillin had a
    mass of:
         a. 22.4 g
         b. 29.1 g
         c. 37.8 g
         d. 152 g
         e. 304 g
46. Combustion analysis of 45.62 mg of toluene, a commonly used hydrocarbon solvent
    gives 35.67 mg of H2O and 152.5 mg of CO2. What is the empirical formula of toluene?
         a. C7H8
         b. C6H6
         c. C6H8
         d. C12H16
         e. C14H16
47. What is the percentage of carbon in dimethylsulfoxide, C2H6SO?
         a. 7.74%
         b. 20.6%
         c. 30.7%
         d. 60.0%
         e. 79.8%
48. A compound of nitrogen and oxygen is analyzed, and a sample wieghing 1.587 g is found
    to contain 0.483 g N and 1.104 O. What is the empirical formula of the compound?
         a. NO
         b. NO2
         c. N2O2
         d. N2O4
         e. N2O5
49. If the mass of a sulfur sample containing 1.0 x 1011 atoms is 5.313 picograms, how much
    does 1 mole of sulfur weigh?
         a. 64 g
         b. 32 g
         c. 16 g
         d. 8.0 g
         e. 4.0 g
50. An unknown element, X, reacts with chlorine to form an ionic compound XCl2. If the X
    ion has 18 electrons, the element X is:
         a. Al
         b. Ca
         c. Mg
         d. Na
         e. Si
51. How many grams of hydrogen are in 46 g of CH4O?
         a. 0.36
         b. 1.5
         c. 2.8
         d. 4.0
         e. 5.8
52. When the equation:

                                C57H110O6 + O2 --> H2O + CO2

   is balanced using smallest whole numbers, the coefficient of oxygen is:

       a. 1
       b. 3
       c. 84
       d. 163
       e. 338
53. Heptane (C7H16) combusts with O2 to produce CO2 and H2O. If the theoretical yield of
    CO2 is 247.8 g, how many grams of heptane are used in this reaction assuming unlimited
    quantity of O2?

                                C7H16 + 11O2 --> 8H2O + 7CO2

       a.   80.62 g
       b.   100.2 g
       c.   161.2 g
       d.   564.3 g
       e.   cannot be determined without knowing the amount of H2O produced since it
            contains the hydrogen from heptane.
54. In an experiment, 7.36 g of zinc and excess sulfur, S8, were mixed and heated. The
    substances react according to the following unbalanced chemical equation:

                                        Zn + S8 --> ZnS

   The amount of zinc sulfide that can be produced by the reaction mixture is:
        a.   0.110 g
        b.   1.10 g
        c.   2.20 g
        d.   11.0 g
        e.   22.0 g

                       The following two questions refer to the reaction:

                           2C2H2(g) + 5O2(g) --> 4CO2(g) + 2H2O(g)

55. If 10.0 g of C2H2 (molecular mass = 26.04 amu) and 10.0 g of O2 (molecular mass =
    32.00 amu) reacted, the mass of CO2 that can be produced theoretically is numerically (in
    g):
         a. 5.50
         b. 11.0
         c. 16.9
         d. 33.8
         e. none of these
56. If, in fact, 5.50 g of CO2 are actually produced, the percent yield (by weight) is
    numerically:
         a. 16.3
         b. 32.5
         c. 50.0
         d. 100.
         e. none of these
57. If 3 moles of HCl are added to 2 moles of NaOH and the following reaction proceeds,
    what will be in the reaction vessel when the reaction comes to completion (and the
    reaction is not reversible)?

                                 HCl + NaOH --> H2O + NaCl

         a. H2O and HCl
         b. HCl and NaCl
         c. H2O and NaCl
         d. H2O, NaCl, and HCl
         e. H2O, NaCl, NaOH, and HCl
58. A substance was determined to be 49.9% oxygen, 37.5% carbon and 12.6% hydrogen by
    mass. What is the proper empirical formula for this compound?
         a. C2H3O
         b. CH4O
         c. CH2O
         d. CHO
         e. CH3CO2H
59. In lecture we reacted hydrogen and oxygen to form water. If 1.0 g of H2 was reacted with
    10.0 g of O2, what is the amount of H2O (in grams) that could be produced?

                                  2H2(g) + O2(g) --> 2H2O(g)

        a. 4.0 g
        b. 8.0 g
       c. 9.0 g
       d. 11 g
       e. 16 g
60. Consider the following UNBALANCED combustion reaction:

                            ___ CH4 + ___ O2 --> ___ CO2 + ___ H2O

    After balancing the reaction, if 4 mol of CH4 is combusted with 4 mol of oxygen, how
    many moles of CH4 are left over?

      a. 0
      b. 1
      c. 2
      d. 3
      e. 4
61. What is the stoichiometric coefficient for sulfuric acid in the following reaction?

                     ___ Fe2O3(s) + ___ H2SO4 --> ___ Fe2(SO4)3 + ___ H2O

        a. 1
        b. 2
        c. 3
        d. 4
        e. 5
62. How much ammonia, NH3, can be obtained from the reaction of 10.0 g of H2 and 80.0 g
    of N2?

                                        N2 + 3H2 --> 2NH3

       a. 28.4 g
       b. 48.6 g
       c. 56.2 g
       d. 90.0 g
       e. 97.1 g
63. How many sodium atoms are in 6.0 g of Na3N?
       a. 3.6 x 1024
       b. 4.6 x 1022
       c. 1.3 x 1023
       d. 0.22
       e. 0.072
64. What is the coefficient of H2O when the following reaction is properly balanced with the
    smallest integers?

                             ___Na + ___H2O --> ___NaOH + ___H2

        a.   1
        b.   2
        c.   3
        d.   4
        e.   5
65. What is the mass percent composition of F in KrF2? (molar mass = 121.80 g)
         a. 18.3%
         b. 145.3%
         c. 68.8%
         d. 81.5%
         e. 31.2%
66. What is the empirical formula of a compound that contains 15.94% boron and 84.06%
    fluorine by mass?
         a. BF
         b. BF2
         c. B2F3
         d. BF3
         e. B3F4
67. A certain compound was found to contain 67.6% C, 22.5% O, and 9.9% H. If the
    molecular weight of the compound was found to be approximately 142 g/mol, what is the
    correct molecular formula for the compound?
         a. C5H2O5
         b. C6H6O4
         c. C7H10O3
         d. C8H14O2
         e. C8H12O2
68. If equal volumes (1.0 L each) of hydrogen and oxygen are mixed and ignited, what is the
    total volume (products and left over reactants) after reaction, assuming constant
    temperature and pressure? [Note: all reactants and products are gases]
         a. 1.0 L
         b. 1.5 L
         c. 2.0 L
         d. 2.5 L
         e. 3.0 L
69. For the following reaction, if 10.0 g of each reactant are available, how many grams of
    product will be produced? [Note, you will need to balance the reaction before solving.]

                           _____Ca(s) + _____O2(g) --> _____CaO(s)

      a. 5.43 g
      b. 7.94
      c. 14.0 g
      d. 20.0 g
      e. it cannot be determined
70. What is the product of this hypothetical reaction?

                                      3A2B3 + B3 --> 6 ???

       a. AB
       b. AB2
       c. AB3
       d. A2B
       e. A3B
71. How many grams of water are produced in the combustion of 17.3 g of glucose
    (C6H12O6) to form water and carbon dioxide? [MW: C6H12O6 = 180.1]
        a. 10.4 g
        b. 17.3 g
        c. 18.4 g
        d. 21.2 g
        e. 34.6 g
72. If 30.0 g C6H6 (molecular weight, 78.11 amu) react with 65.0 g Br2 (molecular weight,
    159.80 amu) according to the reaction,

                                 C6H6 + Br2 --> C6H5Br + HBr

    56.7 g C6H5Br (molecular weight, 157.0 amu) result. The percent theoretical yield of
    C6H5Br is numerically:

       a. 38.4
       b. 40.7
       c. 88.7
       d. 94.0
       e. None of these are close to the correct answer.
73. Commercial bronze, an alloy of Zn and Cu, reacts with hydrochloric acid as follows:

                            Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g)

    Copper does not react with HCl. When 0.507 g of bronze reacts with excess HCl, 0.0985
    grams of ZnCl2 is produced. The % by mass of Zn in bronze is closest to:

        a. 9.34%
        b. 19.34%
        c. 30.34%
        d. 69.66%
        e. 90.66%
74. When 2 moles of KOH are added to 3 moles of HI and the following reaction proceeds,
    what will be in the final mixture when the reaction comes to completion? (The reaction is
    not reversible.)

                                    KOH + HI --> KI + H2O

       a. HI and KI
       b. KI and H2O
       c. HI and H2O
       d. HI, KI and H2O
       e. KOH, HI, KI and H2O
75. The reaction between oxygen and carbon monoxide can be represented by the following
    equations:

                                  1/2O2(g) + CO(g) --> CO2(g)

                                  O2(g) + 2CO(g) --> 2CO2(g)

    Consider an initial reaction mixture as shown in the following diagram:
    Assuming that the reaction illustrated above goes to completion, the product mixture can
    be represented by:




76. Magnesium metal burns in oxygen to form magnesium oxide, MgO. The theoretical yield
    of magnesium oxide from a reaction mixture containing 1.204 x 1024 Mg atoms and 25.0
    g oxygen gas is: [AW: Mg = 24.31; O = 16.00]
        a. 0.391 mol.
        b. 0.781 mol.
        c. 1.56 mol.
        d. 2.00 mol.
        e. 2.78 mol.
77. How many moles of ions are there per mole of Al2(SO4)3?
        a. 17
        b. 6
        c. 5
        d. 3
        e. 1
78. A fuel mixture of two liquids, hydrazine (N2H4) and dinitrogen tetraoxide (N2O4) ignite to
    form nitrogen gas and water vapor. How many grams of nitrogen gas form when exactly
    100.0 g N2H4 and 200.0 g of N2O4 are mixed? (Assume the reaction goes to completion.)
        a. 662 g N2
        b. 331 g N2
        c. 183 g N2
        d. 131 g N2
        e. 31 g N2
79. The elemental analysis of a sample of ionic compound gave the following results: 2.82 g
    Na, 4.35 g Cl, and 7.83 g O. The empirical formula of this compound is:
        a. Na0.12ClO2
        b. NaClO2
        c. NaClO3
        d. NaClO4
        e. Na2ClO4
80. The chief ore of manganese is an oxide known as pyrolusite, which is 36.8% O and
    63.2% Mn by mass. Which of the following oxides of manganese is pyrolusite? [At Wts:
    O = 16.00 amu; Mn = 54.94 amu]
        a. MnO
        b. MnO2
        c. Mn2O3
        d. MnO3
        e. Mn2O7
81. Calculate the mass of CO2 produced when 10.0 g of methane (CH4) are burned. [At Wts:
    C = 12.01 amu; H = 1.008 amu; O = 16.00 amu]
        a. 17.4 g
        b. 10.0 g
        c. 24.7 g
        d. 27.4 g
        e. 4.76 g
82. How many atoms of oxygen are in 2.00 mole of NaAl(OH)2CO3?
        a. 4
        b. 5
        c. 5.00 x 1023
        d. 6.02 x 1023
        e. 6.02 x 1024
83. What is the mass of magnesium oxide (MgO) formed when 10.0 g of Mg react with 10.0
    g of O2 according to the reaction:

                                        2Mg + O2 --> MgO

          a. 0.411 g
          b. 6.58 g
          c. 25.2 g
          d. 16.6 g
          e. 97.2 g
84.   What is the average atomic mass of an iron atom in grams (atomic mass Fe = 55.85
      amu)?
          a. 6.02 x 1023
          b. 1.66 x 10-24
          c. 9.28 x 10-23
          d. 55.85
          e. 55.85 x 10-23
85.   What is the mass percentage of nitrogen in nicotine, C10H14N2 (molar mass = 162.23 g)?
          a. 8.64%
          b. 9.46%
          c. 13.2%
          d. 17.3%
          e. 21.7%
86.   What is the empirical formula of a compound that contains 63.65% N and 36.35% O by
      mass?
          a. NO
          b. NO2
          c. N2O
          d. N2O4
          e. N2O3
87.   How many moles of H2O are produced when 2.5 moles of O2 react in the following
      balanced reaction?
                        C3H8 + 5O2 --> 3CO2 + 4H2O

             a.   5.0
             b.   4.0
             c.   3.0
             d.   2.5
             e.   2.0



Answers

   1.    A
   2.    D
   3.    A
   4.    B
   5.    A
   6.    E
   7.    D
   8.    C
   9.    D
   10.   D
   11.   A
   12.   C
   13.   C
   14.   C
   15.   E
   16.   B
   17.   E
   18.   A
   19.   A
   20.   C
   21.   C
   22.   B
   23.   B
   24.   C
   25.   D
   26.   C
   27.   D
   28.   B
   29.   E
   30.   C
   31.   B
   32.   C
   33.   E
   34.   E
   35.   D
   36.   C
   37.   C
   38.   C
39.   B
40.   D
41.   C
42.   D
43.   B
44.   B
45.   C
46.   A
47.   C
48.   B
49.   B
50.   B
51.   E
52.   D
53.   A
54.   D
55.   B
56.   C
57.   D
58.   B
59.   C
60.   C
61.   C
62.   C
63.   C
64.   B
65.   E
66.   D
67.   D
68.   B
69.   C
70.   B
71.   A
72.   D
73.   A
74.   D
75.   B
76.   C
77.   C
78.   D
79.   D
80.   B
81.   D
82.   E
83.   D
84.   C
85.   D
86.   C
87.   E

				
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