1. Law of Conservation of Mass and Chemical Equations DO NOW: PART A. “REVIEW TIME-COUNTING ATOMS” ON YOUR OWN

2. New Stuff  The Law of Conservation of Mass states that atoms are not created or destroyed during a chemical reaction.  They can only be rearranged into new substance.  A chemical equation is a shorthand way to represent your chemical reaction  Chemical reaction is where two or more substances break and make new bonds to make a new substance with new properties

3. New Stuff  Subscript- how many of each atom  Coefficient- how many of each molecule  Reactants- Substances you are chemically combining to make new substances with new properties  Products - substances you are making through the chemical reaction

4. New Stuff  In a chemical equation, you must show that the Law of Conservation are Mass is being followed. This means:  You have the same number of atoms for each element on each side of the equation  You use coefficients to show that the equation is balanced  You CANNOT change subscripts because that changes the substances you working with

5. New Stuff  To do this, you need to look at the entire formula and count how many atoms you have of each element on each side and then compare them  Na 3 PO 4 + 3KOH  3NaOH + K 3 PO 4  Na=3  P=1  K=3  H= 3  O=12  Na= 3  P=1  K=3  H=3  O=12 BALANCED!

6. New Stuff  MgF 2 + Li 2 CO 3  MgCO 3 + LiF  Mg= 1  Li= 2  O= 3  F= 2  C= 1  Mg= 1  Li= 1  O= 3  F= 1  C= 1 NOT BALANCED!