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Chemical Reactions have two parts- __Reactants__: the original starting substances in the reaction __Products__: the resulting new substance formed from the reaction. An equation //must// be balanced. In a chemical reaction, every atom in the reactants becomes part of the products. Atoms are never lost or gained in a chemical reaction. When writing a chemical reaction, you must show that the number of atoms of each element in the reactants equals the number of atoms of those elements in the products by writing a balanced equation. eg. C + O2 --> CO2* The plus sign separates the formulas of the reactants and products. The arrow (also known as the yields sign) separates the reactants from the products. 1. Count the number of atoms in each elements. 2. Balance an element in one formula by adding a coefficient in front of a formula in either the reactant or the product. 3. Recount all the atoms after adding the coefficient. 4. Persist by trying again and again! 5. Final check by recounting again. //__Rules and Tips:__// 6. Coefficients can only be placed in front of atoms and formulas. 7. Subscripts can never be changed. 8. Leave elements that are on their own for last.
 * __Balancing Chemical Equations__**
 * The Law of** **Conservation of Mass** states that matter cannot be created or destroyed in a chemical reaction.
 * //Procedure for Balancing Chemical Equations//**


 * Accuracy** is important; the symbol or formula for each substance in the reaction must be written correctly. For a compound, determine if it is covalent or ionic and write the appropriate formula. FOr an element,use the proper chemical symbol and be sure to use a subscript of two for the diatomic elements. An equation with an incorrect chemical symbol or formula will not accurately describe the reaction. In fact, even a simple mistake can make a huge difference.

EXAMPLE:

C + O2 ---> CO2* //This equation is balanced!//
 * Reactants || Products ||
 * C=1 || C=1 ||
 * O=2 || O=2 ||

H2 + O2 ---> H2O*

//This equation is not balanced.//
 * Reactants || Products ||
 * H=2 || H=2 ||
 * O=2 || O=1 ||

H2 + O2 ---> 2H2O*


 * Reactants || Products ||
 * H=2 || H=4 ||
 * O=2 || O=2 ||

2H2 + O2 ---> 2H2O*

//This equation is now balanced.
 * Reactants || Products ||
 * H=4 || H=4 ||
 * O=2 || O=2 ||


 * In all formulas, the number __after__ the element is a subscript, NOT a coefficient.//