H2SO4(aq) + Ba(OH)2(aq) | 2 H2O(l) + Na2SO4(aq) | |
4 hydrogens, 1 sulfur, 1 barium, 6 oxygens | 4 hydrogens, 1 sulfur, 1 barium, 6 oxygens | |
2(NH4)3PO4(aq) + 3 CaCl2 | Ca3(PO4)2(s) + 6 NH4Cl(aq) | |
24 hydrogens, 6 nitrogens, 2 phosphoruses, 8 oxygens, 3 calciums, 6 chlorines | 24 hydrogens, 6 nitrogens, 2 phosphoruses, 8 oxygens, 3 calciums, 6 chlorines |
1 C6H12O6(s) + O2(g) CO2(g) + H2O(l)
...in the equation above, balance the O last, because it appears in more than one compound on each side of the equation.
Balancing C's: 1 C6H12O6(s) + O2(g) 6 CO2(g) + H2O(l)
Balancing H's: 1 C6H12O6(s) + O2(g) 6 CO2(g) + 6 H2O(l)
Balancing O's: 1 C6H12O6(s) + 6 O2(g) 6 CO2(g) + 6 H2O(l)
Try a "1" for most complex compound |
1 C3H7S(l) + O2(g) CO2 + H2O(l) + SO2 |
Balancing C's: | 1 C3H7S(l) + O2(g) 3 CO2 + H2O(l) + SO2 |
Balancing S's: | 1 C3H7S(l) + O2(g) 3 CO2 + H2O(l) + 1 SO2 |
Balancing H's: | 1 C3H7S(l) + O2(g) 3 CO2 + 7/2 H2O(l) + 1 SO2 |
2 C3H7S(l) + O2(g) 6 CO2 + 7 H2O(l) + 2 SO2 | |
Balancing O's: | 2 C3H7S(l) + 23/2 O2(g) 6 CO2 + 7 H2O(l) + 2 SO2 |
4 C3H7S(l) + 23 O2(g) 12 CO2 + 14 H2O(l) + 4 SO2 |
Mass balanced but not charge balanced: | Zn(s) + Fe3+(aq) Zn2+(aq) + Fe2+(aq) |
Both mass and charge balanced | Zn(s) + 2 Fe3+(aq) Zn2+(aq) + 2 Fe2+(aq) |
NaOH(aq) + Al2(SO4)3(aq) Al(OH)3(s) + Na2SO4(aq)
Wrong: Na2(OH)3(aq) + Al2(SO4)3(aq) Al(OH)3(s) + Na2(SO4)3(aq)
Correct:
6 NaOH(aq) + Al2(SO4)3(aq) 2 Al(OH)3(s) + 3 Na2SO4(aq)
2(NH4)3PO4(aq) + 3 CaCl2 | Ca3(PO4)2(s) + 6 NH4Cl(aq) | |
24 hydrogens, 6 nitrogens, 2 phosphoruses, 8 oxygens, 3 calciums, 6 chlorines | 24 hydrogens, 6 nitrogens, 2 phosphoruses, 8 oxygens, 3 calciums, 6 chlorines | |
6 ammoniums, 2 phosphates, 3 calciums, 6 chlorides | 6 ammoniums, 2 phosphates, 3 calciums, 6 chlorides |
1 HCl(aq) + 1 NaOH 1 NaCl(aq) + 1 H2O(l)
is more compactly written as
HCl(aq) + NaOH NaCl(aq) + H2O(l)
but both are technically correct!
2 H3O+(aq) + 2 OH- 4 H2O(l)
is more compactly written as
H3O+(aq) + OH- 2 H2O(l)
but both are technically correct!
If you're ready for the recipe now, here's a sketchy outline of the procedure for balancing redox reactions:
H2O(l) H+(aq) + OH-(aq)
to the equation to eliminate hydrogen ions.Copyright © 1997-2010 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101/reactions/update-print-balancing.shtml