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General F003: Oxidation states for metals

  • Page ID
    63674
  • These questions focus on assessing oxidation states of metals. You may wish to review oxidation state before you take the quiz.

    The following questions are "fill in the blank", where you enter the coefficients in order to balance the chemical equation. In cases where only one molecule/formula unit is required, you must enter "1" into the box - do not leave it blank. These questions are for self-testing only, and are not suitable for assignments or exams.

     

    1. Indicate the oxidation state of the metal in each substance. (Worth two points in total)

    (a) CuO
    (b) CuCl
    (c) CuCl2
    (d) CuSO4
    (e) PbCl2
    (f) PbCl4
    (g) PbO
    (h) PbO2
    (i) Al2O3
    (j) Mn2O7
     

     

    2. Indicate the oxidation state of the metal in each substance. (Worth two points in total)

    (a) NaNO3
    (b) Mg(NO3)2
    (c) Al(NO3)3
    (d) CaSO4
    (e) Ce(SO4)2
    (f) Fe2(SO4)3
    (g) Ag2CO3
    (h) BaCO3
    (i) KMnO4
    (j) Na2Cr2O7
     

     

    3. Select the oxidation state for the highlighted metal on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the Fe.

    2FeBr2(s) + Br2(l) → 2FeBr3(s)
    1 2 3 4 5 Oxidn. Redn.  
    Fe on left
    Fe on right
    Oxidation or reduction?

     

    4. Select the oxidation state for the metal on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the Cu.

    2Cu2O(s) + O2(g) → 2CuO(s)
    zero +1 +2 +3 +4 Oxidn. Redn.  
    Cu on left
    Cu on right
    Oxidation or reduction?

     

    5. Select the oxidation state for the tin (Sn) on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the Sn.

    SnCl4(aq) + Na2SO3(aq) + 2NaOH(aq) → SnSO4(s) + 4NaCl(aq) + H2O(l)
    zero +1 +2 +3 +4 Oxidn. Redn.  
    Sn on left
    Sn on right
    Oxidation or reduction?

     

    6. Select the oxidation state for the niobium (Nb) on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the Nb.

    Nb2O5(s) + H2(g) → 2 NbO2(s) + H2O(g)
    +1 +2 +3 +4 +5 Oxidn. Redn.  
    Nb on left
    Nb on right
    Oxidation or reduction?

     

    7. Select the oxidation state for the chromium (Cr) on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the metal.

    K2Cr2O7(aq) + 3C2H5OH(l) +7H2SO4(aq) → Cr2(SO4)3(aq) + K2SO4(aq) + 7H2O(l) + 3CH3CHO(g)
    +2 +3 +4 +5 +6 Oxidn. Redn.  
    Cr on left
    Cr on right
    Oxidation or reduction?

     

    8. Select the oxidation state for the manganese (Mn) on each side of this redox equation, then indicate whether the reaction is an oxidation or a reduction of the Mn.

    2 MnO2(s) + 4 KOH(s) + O2(g) → 2 K2MnO4(s) + 2 H2O(g)
    +3 +4 +5 +6 +7 Oxidn. Redn.  
    Mn on left
    Mn on right
    Oxidation or reduction?

     

    Answers:

    1(a). 2

    1(b). 1

    1(c). 2

    1(d). 2

    1(e). 2

    1(f). 4

    1(g). 2

    1(h). 4

    1(i). 3

    1(j). 7

    2(a). 1

    2(b). 2

    2(c). 3

    2(d). 2

    2(e). 4

    2(f). 3

    2(g). 1

    2(h). 2

    2(i). 7

    2(j). 6

    3. 2,3 Oxidation

    4. +1, +2, Oxidation

    5. +4, +2, Reduction

    6. +5, +4 , Reduction

    7. +6, +3, Reduction

    8. +4, +6, Oxidation