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    Chemistry Problems

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    Question 1
    Consider an electrochemical cell constructed from the following half cells, linked by an external circuit and by a KCl salt bridge:

    an Al(s) electrode in 1.0 M Al(NO3)3 solution
    a Pb(s) electrode in 1.0 M Pb(NO3)2 solution

    What is the balanced overall (net) cell reaction?

    Pb(s) + Al3+(aq) Pb2+(aq) + Al(s)
    3Pb(s) + 2Al3+(aq) 3Pb2+(aq) + 2Al(s)
    3Pb2+(aq) + 2Al(s) 3Pb(s) + 2Al3+(aq)
    Pb2+(aq) + Al(s) Pb(s) + Al3+(aq)

    --------------------------------------------------------------------------------

    Question 2
    Calculate the value of Eocell for the following reaction:

    2Au(s) + 3Ca2+(aq) 2Au3+(aq) + 3Ca(s)

    -4.37 V
    -1.37 V
    -11.6 V
    1.37 V
    4.37 V

    --------------------------------------------------------------------------------

    Question 3
    An electrochemical cell based on the following reaction has a standard cell voltage (Eocell) of 0.48 V.

    Sn(s) + Cu2+(aq) Sn2+(aq) + Cu(s)

    What is the standard reduction potential of tin?

    Sn2+(aq) + 2e- Sn(s)

    -0.14 V
    0.14 V
    -0.82 V
    0.82 V
    None of the above

    --------------------------------------------------------------------------------

    Question 4
    Which chemical species undergoes reduction according to the following cell diagram?

    Sn | Sn2+ || NO3- (acid soln), NO(g) | Pt

    Sn
    Sn2+
    NO3-
    NO
    Pt

    --------------------------------------------------------------------------------

    Question 5
    In the following half equation, which is the oxidizing agent?

    NO3-(aq) + 4H+(aq) + 3e- NO(g) + 2H2O

    NO3-
    H+
    e-
    NO
    H2O

    --------------------------------------------------------------------------------

    Question 6
    Which statement is true in regard to a spontaneous redox reaction?

    Eored is always negative.
    Eocell is always positive.
    Eoox is always positive.
    Eored is always positive.

    --------------------------------------------------------------------------------

    Question 7
    Which of the following species is the strongest oxidizing agent under standard state conditions?

    Ag+(aq)
    H2(g)
    H+(aq)
    Cl2(g)
    Al3+(aq)

    --------------------------------------------------------------------------------

    Question 8
    Calculate the cell emf for the following reaction:

    2Ag+(0.010 M) + H2(1 atm) 2Ag(s) + 2H+ (pH = 10.0)

    1.04 V
    1.27 V
    0.92 V
    0.56 V
    0.80 V

    --------------------------------------------------------------------------------

    Question 9
    A current of 2.50 A was passed through an electrolytic cell containing molten CaCl2 for 4.50 hours. How many moles of calcium metal should be deposited?

    5.83 x 10-5 mol
    0.210 mol
    0.420 mol
    0.840 mol
    1.95 x 109 mol

    --------------------------------------------------------------------------------

    Question 10
    How long will it take to produce 78 g of Al metal by the reduction of Al3+ in an electrolytic cell with a current of 2.0 A?

    0.01 s
    420 s
    13 h
    116 h
    1.0 x 1012 s

    --------------------------------------------------------------------------------

    Question 11
    According to the band theory, which of the following provide(s) an explanation for the high electrical conductivity of metals?

    a partly filled conduction band
    a valence band overlapping an empty conduction band
    a filled valence band
    a large gap between the valence band and the conduction band
    1 and 2
    1 and 3
    3
    3 and 4
    4

    --------------------------------------------------------------------------------

    Question 12
    Which one of the following elements would form p-type semiconductors when added to silicon crystals?

    C
    P
    As
    Ga
    Mg

    --------------------------------------------------------------------------------

    Question 13
    The electron configuration of an Fe2+ ion is ________.

    [Ar]4s24d4
    [Ar]4s23d6
    [Ar]3d3
    [Ar]3d5
    [Ar]3d6

    --------------------------------------------------------------------------------

    Question 14
    How many 3d electrons does a Mn2+ ion have?

    1
    2
    3
    4
    5

    --------------------------------------------------------------------------------

    Question 15
    In the complex ion [Fe(CN)6]4-, the oxidation number of Fe is ________.

    +1
    +2
    +3
    -4
    +6

    --------------------------------------------------------------------------------

    Question 16
    In the complex ion [Co(en)2Br2]+, the oxidation number of Co is ________.

    +1
    +2
    +3
    -2
    -1

    --------------------------------------------------------------------------------

    Question 17
    A bidentate ligand always ________.

    has bonds formed to two metal ions
    has a charge of 2+ or 2-
    forms complex ions with a charge of 2+ or 2-
    has two donor atoms
    has medical uses

    --------------------------------------------------------------------------------

    Question 18
    Which one of the following is a monodentate ligand?

    CN-
    EDTA
    C2O42- (oxalate ion)
    H2NCH2CH2NH2 (ethylenediamine)

    --------------------------------------------------------------------------------

    Question 19
    The best name for [Co(en)2Br2]Br is ________.

    cobalt(III)bis(ethylenediamine) bromide
    dibromobis(ethylenediamine)cobalt(III) bromide
    dibromidedi(ethylenediamine)cobalt(III) bromide
    dibromodiethylenediaaminecobalt(III) bromide
    tribromobis(ethylenediamine)cobalt(III)

    --------------------------------------------------------------------------------

    Question 20
    The correct formula for the dichlorobis(ethylenediamine)chromium(III) ion is ________.

    [Cr(en)2Cl2]3+
    [Cr(en)Cl2]+
    [Cr(en)2Cl2]2+
    [Cr(en)2Cl2]+
    [Cr(en)3Cl2]+

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