1. Counting Atoms and Balancing Equations

2. TRUE or FALSE? A compound is always molecule: A molecule is always a compound

3. Example 1 – Sulfuric AcidO
Number of Molecules:
Atoms H: O: S: S O O H
H2SO4 H O
These are subscripts (small numbers). They indicate the quantity of the atom that appears immediately before the number.

4. Example 2 – Calcium hydroxide
Number of Molecules:
Atoms
Ca: O: H: Ca O O H
Ca(OH)2 H
Sometimes a subscript will appear after brackets. This means that all the atoms inside the brackets are multiplied by this number.

5. Example 3 – Calcium hydroxide… again
3 Ca(OH)2 Ca O H
This is a coefficient. When a coefficient appears before a molecule, it tells you how many of these molecules there are. Multiply ALL atoms in the molecule by this coeffcient.

6. Example 3 – Calcium hydroxide… again
3 Ca(OH)2 Ca O H
Number of Molecules:
Atoms
Ca: O: H:

7. Ca3(PO4)2 Al2(SO4)3 4 Mg(NO3)2 Try these…
Calcium phosphate Aluminum sulfate molecules of Magnesium nitrate
Ca3(PO4) Al2(SO4) Mg(NO3)2

8. Balancing Equations
In a chemical reaction, atoms are rearranged. The number of atoms in the reactants MUST EQUAL the number of atoms in the products. This is the Law of Conservation of Matter: Matter is neither created nor destroyed. It is merely rearranged.

9. Reactants of cellular respirationH O

10. Products of cellular respirationH O

11. Complete p