Balancing Equations

Conservation of Matter Compounds, molecules and elements all have mass. Because these materials all have mass, the number of atoms must be conserved. Therefore, on both sides of an equation the same number of atoms for a particular type of atom must be present or we violate the conservation of matter.

Use the following rules and you should have very few problems balancing equations.

Rule #1: Always make sure you have the correct formulas. Rule #2:Be careful with elements that exist only as diatomic molecules. The diatomic molecules are: H2, N2, O2, F2, Cl2, Br2, and I2

Rule #3: Always balance: A. Atoms or compounds that contains anything other than oxygen or hydrogen first B. Compounds with hydrogen next C. Compounds with oxygen last

Rule #4 :Try balancing compounds by groups first. Ex: if SO42- is present on both sides of the reaction, balance the polyatomic ion as a whole.

Rule #5: Water can be written HOH when OH- is a polyatomic ion used. Rule #6: Coefficients should be whole numbers. Rule #7: Coefficients should be the lowest possible ratios

Rule #7 Example: If your coefficients are 2 6 4 2 Change your coefficients to 1 3 2 1

Rule #8: If the formulas have a really large ratio, you are probably wrong.

Practice S8 + O2 -> SO3 S8 + 12O2 -> 8SO3 N2 + H2 -> NH3

Practice N2 + 3H2 -> 2NH3 KO2 + CO2 -> K2CO3 + O2

Practice C4H8 + O2 -> CO2 + H2O C4H8 + 6O2 -> 4CO2 + 4H2O