Balancing Equations
All chemical formulas should be represented in a balanced form, meaning that the number of atoms of each element are the same on both sides of the equation. In order to do this, the coefficients must be so, so that the number of atoms of each element is the same on both sides of the equation. The number of atoms of each element can be determined by multiplying the coefficient of the element by the subscript next to it. For example: 2Pb3O2 in this equation, there are 6 atoms of Pb (lead) and 4 atoms of O (oxygen).
Balancing equations: Br3 + O2 à BrO
In this equation we have on the left side (aka the reactant side), 3Br, 2O
On the right side (a.k.a the product side) we have
1Br, 1O
In order to balance this equation, we will adjust the coefficients (using trial and error) to achieve a balanced form which is:
2Br3 + 3O2 à 6BrO
Here, the same number of atoms of Bromine are on the left side as they are on the right side, and the same number of atoms of Oxygen are on the left side as they are on the right side.
Also, sometimes parenthesis are used: (SO4)3
In this example, the subscript 3 applies to both of the elements inside the parenthesis, so there are 3 atoms of Sulfur (S) and 12 atoms of Oxygen (O). The number outside the parenthesis is multiplied by the number of atoms that the element contains inside the parenthesis.
Other Examples
(see link at bottom of page for answers)
1. Cu +H2O à CuO + H2
2. Al(NO3)3 + NaOH à Al(OH)3 + NaNO3
3. KNO3 à KNO2 +O2
4. Fe + H2SO4 à Fe2(SO4)3 +H2
5. O2 + CS2 à CO2 + SO2
6. Cu + Cl2 à CuCl2
7. Mg + N2 à Mg3N2
8. C + O2 àCO2
9. CO + O2 àCO2
10. K + H2O àKOH + H2
11. NaOH + H2SO4 àNaSO4 + H2O
12. Al + H2SO4 àAl2(SO4)3 + H2
13. NH4NO2 àN2 + H2O
14. NH3 + CuO àCu + N2 + H2O
15. C2H6 + O2 àH2O + CO2
16. P4O10 + H2O àH3PO4
Practice Balancing More Equations