Balancing Equations

• A chemical equation is a scientific "sentence" that uses chemical formulas and symbols to describe chemical reactions.
• During chemical reactions, atoms are rearranged as chemical bonds are broken and formed.
• The rearrangement of atoms in a chemical equation can be easily seen.
• In a chemical equation, the reactants are placed to the left of the arrow.
• The reactants in a chemical equation are the substances that take part in the reaction.
• The products in a chemical equation are the new substances created during the chemical reaction.
• The arrow in a chemical equation means "produces" or "yields."
• When the number of atoms of each element in the reactants matches the number of atoms of each element in the products, the chemical equation is said to be balanced.
• A balanced chemical equation follows the law of conservation, which says that matter can neither be created nor destroyed.
• A chemical equation uses coefficients to indicate the number of molecules of each substance in the reactants and in the products.
• Coefficients appear in front of a chemical formula (except for the number one, which is "invisible").
• The large number 2 in 20, is a coefficient.
• Coefficients indicate how many molecules, atoms, or diatomic molocules take part in the reaction.
• Coefficients are used to balance equations.
• After balancing an equation, reduce all coefficients to lowest terms.
• The distributive property with coefficients is used when counting atoms.
• In an equation, the number of atoms of each element in the reactants is the same as the number of atoms of each element in the products.
• In this equation, the phosphate (PO,) radical can be kept together because it appears on both sides of the arrow, however, the hydroxide (OH) radical cannot as it dissociates during the reaction.
• To determine whether an equation is balanced, the atoms in the reactants and the atoms in the products are counted.
• Recount after balancing to make sure that the number of atoms in the reactants equals the number of atoms in the products.
• To balance an equation that is not balanced, follow these steps: count the atoms of each element in the reactants and in the products, line up the same atoms across from one another, add, delete or change coefficients to balance, and always balance in this order: diatomic molecules first (if they appear on both sides of the arrow), metals nonmetals, hydrogen last.
• If the equation below is not balanced, the number of atoms of each element in the reactants and in the products do not match.
• An equation is balanced when the number of atoms in the reactants equals the number of atoms in the products.