Balancing Chemical Equations
• A chemical reaction is the process by which the atoms the atoms of one or more
substances are rearranged to form different substances.
• Some chemical reactions are hard to see while others are very obvious as they release
large amounts of energy or there is a color change.
• The starting substances in a chemical reaction are the reactants and the ending
substances are the products.
• A chemical equation is one in which the chemical formulas of the reactants and the
products are shown separated by an arrow pointing to the products (right).
• The Law of Conservation of Matter states that matter cannot be created or destroyed in
a chemical reaction. Therefore, the same number of each element must be present in
the reactants and the products.
• This is called a balanced equation. Coefficients are numbers placed in from of the
different compounds in the chemical equation to balance it.
Step 1 – Write the skeleton equation. Be sure to put the reactants on the left and the
products on the right.
NaOH + CaBr2 Ca(OH)2 + NaBr
Step 2 – Count the atoms of each element of each side.
Reactant: Na – 1 Product: Na - 1
OH – 1 OH - 2
Ca – 1 Ca - 1
Br – 2 Br – 1
Step 3 – Adjust the coefficients.
2NaOH + CaBr2 Ca(OH)2 + 2NaBr
Step 4 – Check to see that the coefficients are at the lowest possible ratio.
Step 5 – Recount the atoms
Reactant: Na – 2 Product: Na - 2
OH – 2 OH - 2
Ca – 1 Ca - 1
Br – 2 Br – 2