# Examples of Balanced Chemical Equations A balanced chemical equation has the same number of atoms of each element on both sides of the reaction arrow. (photo: Polina Tankilevitch)

A balanced chemical equation represents a chemical reaction as chemical formulas and numbers. Here is a collection of more than 10 balanced chemical equations. Use them as homework examples or to review the principles of balancing equations.

### Balanced Equation Basics

• Elements are represented using their element symbols.
• The left side of the reaction lists the reactants, the right side lists the products, and the reaction arrow indicates the direction in which the reaction proceeds.
• In a balanced chemical equation, the same number and type of atoms are present on both sides of the reaction arrow.
• The number in front of a chemical formula is its coefficient and is the number of moles of that element or compound. If there is 1 mole of a substance, the number is omitted (e.g., write CO instead of 1 CO).
• Subscripts after an element symbol indicate the number of atoms of the element in a substance. If there is no subscript, it means there is one atom of that element.
• The total number of atoms in a compound is the subscript multiplied by the coefficient (e.g., 4H2O contains 4 x 2 = 8 atoms of hydrogen and 1 x 4 = 4 atoms of oxygen).

### Balanced Chemical Equations

6 CO2 + 6 H2O → C6H12O6 + 6 O2 (balanced equation for photosynthesis)

2 AgI + Na2S → Ag2S + 2 NaI

Ba3N2 + 6 H2O → 3 Ba(OH)2 + 2 NH3

3 CaCl2 + 2 Na3PO4 → Ca3(PO4)2 + 6 NaCl

4 FeS + 7 O2 → 2 Fe2O3 + 4 SO2

PCl5 + 4 H2O → H3PO4 + 5 HCl

2 As + 6 NaOH → 2 Na3AsO3 + 3 H2

3 Hg(OH)2 + 2 H3PO4 → Hg3(PO4)2 + 6 H2O

12 HClO4 + P4O10 → 4 H3PO4 + 6 Cl2O7

8 CO + 17 H2 → C8H18 + 8 H2O

10 KClO3 + 3 P4 → 3 P4O10 + 10 KCl

SnO2 + 2 H2 → Sn + 2 H2O

3 KOH + H3PO4 → K3PO4 + 3 H2O

2 KNO3 + H2CO3 → K2CO3 + 2 HNO3

Na3PO4 + 3 HCl → 3 NaCl + H3PO4

TiCl4 + 2 H2O → TiO2 + 4 HCl

C2H6O + 3 O2 → 2 CO2 + 3 H2O

2 Fe + 6 HC2H3O2 → 2 Fe(C2H3O2)3 + 3 H2

4 NH3 + 5 O2 → 4 NO + 6 H2O

B2Br6 + 6 HNO3 → 2 B(NO3)3 + 6 HBr

4 NH4OH + KAl(SO4)2·12H2O → Al(OH)3 + 2 (NH4)2SO4 + KOH + 12 H2O

### Balanced Chemical Equations as Word Equations

Sometimes you may be asked to say a balanced chemical equation as a word equation. To read an equation aloud, you need to know the chemical name of the substance. The coefficients are read as “X moles of”, the subscripts aren’t stated because they are implied in the chemical name, and the reaction arrow is read as “yields” or “forms”.

For example, the following equation:

4 NH3 + 5 O2 → 4 NO + 6 H2O

Four moles of ammonia plus five moles of oxygen yields four moles of nitric oxide plus six moles of water.