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7.4.5: Practice Classifying Reactions

  • Page ID
    236043
  • Classify Reactions

    Exercise \(\PageIndex{1}\)

    Classify each reaction below as combination, decomposition, single displacement, double displacement, or combustion.

    CaCO3 (s) \(\rightarrow\) CO2 (g) + CaO (s)

    Answer

    decomposition

    2 N2 (g) + 5 O2 (g) \(\rightarrow\) 2 N2O5 (g)

    Answer

    combination

    C5H10O (l) + 7 O2 (g) \(\rightarrow\) 5 CO2 (g) + 5 H2O (g)

    Answer

    combustion

    ZnCl2 (aq) + 2 AgNO3 (aq) \(\rightarrow\) Zn(NO3)2 (aq) + 2 AgCl (s)

    Answer

    double displacement

    Cl2 (g) + 2 KBr (aq) \(\rightarrow\) Br2 (l) + 2 KCl (aq)

    Answer

    single displacement

    2 H2 (g) + O2 (g) \(\rightarrow\) 2 H2O (g)

    Answer

    combination

    Mg (s) + HCl (aq) \(\rightarrow\) MgCl2 (aq) + H2 (g)

    Answer

    single displacement

    Total Ionic and Net Ionic Equations

    Exercise \(\PageIndex{1}\)

    Give the total ionic equation ("complete ionic equation") and the net ionic equation for each reaction below.

    ZnCl2 (aq) + 2 AgNO3 (aq) \(\rightarrow\) Zn(NO3)2 (aq) + 2 AgCl (s)

    Total Ionic

    Zn2+(aq) + 2 Cl1–(aq) + 2 Ag1+(aq) + 2 NO31–(aq) \(\rightarrow\) Zn2+(aq) + 2 NO31–(aq) + 2 AgCl (s)

    Net Ionic

    2 Cl1–(aq) + 2 Ag1+(aq) \(\rightarrow\) 2 AgCl (s)

    H3PO4 (aq) + 3 NaOH (aq) \(\rightarrow\) Na3PO4 (aq) + 3 H2(l)

    Total Ionic

    3 H1+(aq) + PO43– (aq) + 3 Na1+(aq) + 3 OH1–(aq) \(\rightarrow\) 3 Na1+(aq) + PO43– (aq) + 3 H2(l)

    Net Ionic

    3 H1+(aq) + 3 OH1–(aq) \(\rightarrow\) 3 H2(l)

    Precipitation Reactions

    Exercise \(\PageIndex{1}\)

    Which of the following compounds would not be soluble in water (and would form a solid precipitate)?

    LiCl    Pb(NO3)2    BaBr2    CaSO4    AgBr    Zn(C2H3O2)2    MgSO4    CaCl2    K2CO3    NiPO4

    Answer

    CaSO4    AgBr    NiPO4

    For each of the reactions below, predict the products formed. Use the correct chemical formulas. Then balance the reaction and tell which product would be soluble ("aq" aqueous solution) and which would be insoluble ("s" solid precipitate).

    CuCl2 (aq) + KOH (aq) \(\rightarrow\)

    Answer

    CuCl2 (aq) + 2 KOH (aq) \(\rightarrow\) 2 KCl (aq) + Cu(OH)2 (s)

    CaCl2 (aq) + Pb(NO3)2 (aq) \(\rightarrow\)

    Answer

    CaCl2 (aq) + Pb(NO3)2 (aq) \(\rightarrow\) Ca(NO3)2 (aq) + PbCl2 (s)

    Ba(ClO3)2 (aq) + Li2SO4 (aq) \(\rightarrow\)

    Answer

    Ba(ClO3)2 (aq) + Li2SO4 (aq) \(\rightarrow\) 2 LiClO3 (aq) + BaSO4 (s)

    Oxidation and Reduction

    Exercise \(\PageIndex{1}\)

    For each reaction below, tell which element is being oxidized and which is being reduced.

    Mg (s) + HCl (aq) \(\rightarrow\) MgCl2 (aq) + H2 (g)

    Answer

    Mg is being oxidized (0 to +2 charge),  Cl has no change (–1 to –1 charge), H is being reduced (+1 to 0 charge)

    2 Al (s) + 3 Br2 (l) \(\rightarrow\) 2 AlBr3 (s)

    Answer

    Al is being oxidized (0 to +3 charge), Br is being reduced (0 to –1 charge)

    Cl2 (g) + 2 KBr (aq) \(\rightarrow\) Br2 (l) + 2 KCl (aq)

    Answer

    Cl is being reduced (0 to –1 charge), K is not changing (+1 to +1 charge), Br is being oxidized (–1 to 0 charge).

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