1. Counting Atoms!! Oct 5 th 2012

2. Reactants and Formulas Write: HCl + NaOH  NaCl + H 2 O And label the reactants and the products

3. The law of Conservation of Mass- the mass of substances in a closed system will remain constant, no matter what processes are acting inside the system.

4. We know what is a formula We have seen that a chemical formula is… A number of atoms that make up ONE compound Ex. Mg 2 O So this example will have what number of elements? Mg:2 O:1 Therefore….2 Mg and 1 Oxygen is the chemical formula for making the compound= Mg 2 O

5. But wait….there is more! Vocab: Coefficients- A number in front of a chemical formula(compound) used to tell the number of compounds. Ex. (The #2 in 2Pb 3 O 4 )

7. Subscripts Vocab: Subscripts: A SMALL number written after an element in a chemical formula telling how many of that element is in the formula. Ex. FeS 2  this two is a subscript

8. Write in IAN please

9. Alright, how many total atoms of each Mg 2 P 2 O 7 = AuCl 3 = C 4 H 12 O 2 = 2C 3 H 4 CaMgSi 3 O 8 = CaHPO 3 + 3H 2 O = 3CuCl 2 = Pb 3 O 4 =