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Balancing Reactions 2

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Updated 2009-03-26 23:20

Balancing Chemical Reactions

  In each reaction below on the left, several coefficients are missing.

The coefficients in the right column fill in the blanks in the left column.

All coefficients have been rescaled to be the lowest possible integers.

 

  While you could try to memorize all these reactions and their coefficients,
it is better to use these as practice examples.
Just make sure the quantities of each element on the left side of each equation
match the quantities of each element on the right side of each equation.

 

3 H2O contains 6 H atoms and 3 O atoms,
5 Fe2O3 contains 10 Fe atoms and 15 O atoms, and

3 NiCl2•6H2O contains 3 Ni atoms, 6 Cl atoms, 36 H atoms, and 18 O atoms.

 

ReactionMissing Coefficients
___ CH4(g) + ___ O2(g) -> ___ CO2(g) + ___ H2O(g)1, 2, 1, 2
___ HCl(aq) + ___ NaHCO3(s) ->
___ CO2(g)+ ___ H2O(l) + NaCl(aq)
1, 1, 1, 1
___ C2H5OH(l) + ___ O2(g) ->
___ CO2(g) + ___ H2O(g)
1, 3, 2, 3
___ (NH4)2Cr2O7(s) ->
___ Cr2O3(s) + ___ N2(s) + ___ H2O(g)
1, 1, 1, 4
___ C3H8(g) + ___ O2(g) -> ___ CO2(g) + ___ H2O(g)1, 5, 3, 4
___ NH3(g) + ___ O2(g) -> ___ NO(g) + ___ H2O(g)4, 5, 4, 6
___ LiOH(s) + ___ CO2(g) ->
___ Li2CO3(s) + ___ H2O(l)
2, 1, 1, 1
___ NaHCO3(s) + ___ HCl(aq) ->
___ NaCl(aq) + ___ H2O(l) + CO2(aq)
1, 1, 1, 1
___ Mg(OH)2(s) + ___ HCl(aq) ->
___ H2O(l) + ___ MgCl2(aq)
1, 2, 2, 1
memorize

 

ReactionMissing Coefficients
___ CH4(g) + ___ H2O(g) -> ___ H2(g) + ___ CO(g)1, 1, 3, 1
___ NH3(g) + ___ CuO(s) ->
___ N2(g) + 3 Cu(s) + ___ H2O(g)
2, 3, 1, 3
___ FeCr2O4(s) + 8 K2CO3(s) + ___ O2(g) ->
___ K2CrO4(s) + 2 Fe2O3(s) + ___ CO2(g)
4, 7, 8, 8
___ Ca3(PO4)2(s) + ___ H2SO4(aq) ->
___ CaSO4(s) + ___ H3PO4(aq)
1, 3, 3, 2
___ NaHCO3(aq) + ___ C6H8O7(aq) ->
___ CO2(g) + ___ H2O(l) + Na3C6H5O7(aq)
3, 1, 3, 3
___ C7H6O3 + ___ C4H6O3 ->
___ C9H8O4 + ___ H2O
2, 1, 2, 1
___ NH3(g) + ___ O2(g) + ___ CH4(g) ->
___ HCN(g) + 6 H2O(g)
2, 3, 2, 2
___ C3H6(g) + ___ NH3(g) + 3 O2(g) ->
___ C3H3N(g) + ___ H2O(g)
2, 2, 2, 6
___ C6H10O4(l) + ___ NH3(g) + 4 H2(g) ->
___ C6H16N2(l) + ___ H2O(l)
1, 2, 1, 4
___ K2PtCl4(aq) + ___ NH3(aq) ->
___ Pt(NH3)2Cl2(s) + ___ KCl(aq)
1, 2, 1, 2
memorize

 

ReactionMissing Coefficients
___ PbS(s) + ___ O2(g) -> ___ PbO(s) + ___ SO2(g)2, 3, 2, 2
___ PbO(s) + ___ CO(g) -> ___ Pb(s) + ___ CO2(g)1, 1, 1, 1
___ H3C6H5O7(aq) + ___ NaOH(aq) ->
___ H2O(l) + ___ Na3C6H5O7(aq)
1, 3, 3, 1
___ Ca(s) + ___ H2O(l) -> ___ Ca(OH)2(aq) + ___ H2(g)1, 2, 1, 1
___ H2SO4(aq) + ___ NaOH(aq) ->
___ H2O(l) + ___ Na2SO4(aq)
1, 2, 2, 1
___ Al(s) + 3 NH4ClO4(s) ->
___ Al2O3(s) + AlCl3(s) + ___ NO(g) + ___ H2O(g)
3, 1, 3, 6
___ NO2(g) + ___ H2O(l) -> ___ HNO3(aq) + ___ NO(g)3, 1, 2, 1
___ MnO2(s) + ___ Al(s) -> ___ Mn(s) + ___ Al2O3(s)3, 4, 3, 2
___ PH3(g) + ___ O2(g) -> ___ P4O10(s) + ___ H2O(g)4, 8, 1, 6
___ NH3(g) + ___ CO2(g) + heat + pressure ->
___ H2NCONH2(s) + ___ H2O(g)
2, 1, 1, 1
___ B2H6(g) + ___ O2(g) -> ___ B2O3(s) + ___ H2O(g)1, 3, 1, 3
memorize

 

ReactionMissing Coefficients
___ C(s) + ___ H2(g) + ___ O2(g) -> ___ CH3OH(l)2, 4, 1, 2
___ NH3(g) + ___ O2(g) -> ___ NO2(g) + ___ H2O(l)4, 7, 4, 6
___ C8H18(l) + ___ O2(g) ->
___ CO2(g) + ___ H2O(l)
2, 25, 16, 18
___ C(s) + ___ H2O(g) -> ___ H2(g) + ___ CO(g)1, 1, 1, 1
___ H2O + ___ SO2 + I2 -> ___ H2SO4 + ___ HI2, 1, 1, 2
___ H2SO4 -> ___ SO2 + ___ H2O + ___ O22, 2, 2, 1
___ N2(g) + ___ O2(g) + ___ H2(g) -> ___ HNO3(l)1, 3, 1, 2
___ Fe2O3(s) + ___ CO(g) -> ___ Fe(s) + ___ CO2(g)1, 3, 2, 3
___ Fe2O3(s) + ___ CO(g) ->
___ Fe3O4(s) + ___ CO2(g)
3, 1, 2, 1
___ Fe3O4(s) + ___ CO(g) -> ___ FeO(s) + ___ CO2(g)1, 1, 3, 1
___ FeO(s) + ___ CO(g) -> ___ Fe(s) + ___ CO2(g)1, 1, 1, 1
memorize

 

ReactionMissing Coefficients
___ C2H2(g) + ___ O2(g) -> ___ CO2(g) + ___ H2O(l)2, 5, 4, 2
___ NO(g) + ___ O3(g) -> ___ NO2(g) + ___ O2(g)1, 1, 1, 1
___ C6H4(OH)2(aq) + ___ H2O2(aq) ->
___ C6H4O2(aq) + ___ H2O(l)
1, 1, 1, 2
___ NH3(g) + ___ O2(g) + 2 CH4(g) ->
___ HCN(g) + ___ H2O(g)
2, 3, 2, 6
___ Ca3(PO4)2(s) + ___ H2SO4(l) ->
___ CaSO4(s) + ___ H3PO4(l)
1, 3, 3, 2
___ Al(s) + ___ Fe2O3(s) -> ___ Al2O3(s) + ___ Fe(s)2, 1, 1, 2
___ NH3(g) + ___ O2(g) -> ___ NO(g) + ___ H2O(g)4, 5, 4, 6
___ NO2(g) + ___ H2O(l) -> ___ HNO3(aq) + ___ NO(g)3, 1, 2, 1
___ Na(s) + ___ H2O(l) -> ___ NaOH(aq) + ___ H2(g)2, 2, 2, 1
___ Na(s) + ___ CO2(g) -> ___ Na2O(s) + ___ CO(g)2, 1, 1, 1
memorize

 

ReactionMissing Coefficients
___ Al(s) + ___ NH4ClO4(s) ->
___ Al2O3(s) + ___ AlCl3(s) + 3 NO(g) + 6 H2O(g)
3, 3, 1, 1
___ N2O4(l) + ___ N2H3CH3(l) ->
___ H2O(g) + ___ N2(g) + 4 CO2(g)
5, 4, 12, 9
___ TiCl4(g) + ___ H2O(g) -> ___ TiO2(s) + ___ HCl(g)1, 2, 1, 4
___ C2H4(g) + ___ O3(g) ->
___ CH3CHO(g) + ___ O2(g)
1, 1, 1, 1
___ O3(g) + ___ NO(g) -> ___ NO2(g) + ___ O2(g)1, 1, 1, 1
___ CO2(g) + ___ H2O(l) + sunlight ->
___ C6H12O6(s) + ___ O2(g)
6, 6, 1, 6
___ HCl(sq) + ___ Ba(OH)2(aq) ->
___ BaCl2(aq) + ___ H2O(l)
2, 1, 1, 2
___ HNO3(aq) + ___ Na2CO3(s) ->
___ NaNO3(aq) + ___ H2O(l) + CO2(g)
2, 1, 2, 1
___ C2H2(g) + ___ O2(g) -> ___ CO2(g) + ___ H2O(g)2, 5, 4, 2
___ K(s) + ___ H2O(l) -> ___ KOH(aq) + ___ H2(g)2, 2, 2, 1
memorize

 

Balancing Reactions has more examples.

 

Reference: Chapters 3-6 of "Chemistry" by Steven S. Zumdahl, 1986,
D. C. Heath and Company (ISBN=0-669-04529-2).