Law of Conservation of Mass and Chemical Equations Do now: Grab sheet from Front desk Do Part A. “Review Time-counting atoms” on your own

Review Time 2HCl H-2 Cl-2 C2H6 C-2 H-6 2MgO Mg-2 O-2 3Al(OH)3 Al-3 O-9 H-9 P4O10 P-4 O-10 H2O2 H-2 O-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

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

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

New Stuff Na3PO4 + 3KOH  3NaOH + K3PO4 Na=3 P=1 K=3 H= 3 O=7 Na= 3 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 Na3PO4 + 3KOH  3NaOH + K3PO4 Na=3 P=1 K=3 H= 3 O=7 Na= 3 P=1 K=3 H=3 O=7 BALANCED!

New Stuff MgF2 + Li2CO3  MgCO3 + LiF Mg= 1 Li= 1 O= 3 F= 1 C= 1 Mg= 1 NOT BALANCED!