1. Balancing Equations

2. Reactions:
reactants  products
We say “reactants yield products.”

3. Memory Lane: ie: What we start with, we must end with.
Remember – The law of conservation of mass?!
“In a chemical reaction, mass cannot be created or destroyed.”
ie: What we start with, we must end with.

4. Is mass conserved in this reaction?
Conservation of Mass?!
Na + Cl2  NaCl
Is mass conserved in this reaction?

5. SUBSCRIPTS and COEFFICIENTS
2Na + Cl2  2NaCl
COEFFICIENTS
SUBSCRIPTS

6. BALANCING:
Step #1:
Take inventory.

7. BALANCING:
Step #2:
Attack

8. BALANCING:
Step #3:
Re-inventory

9. BALANCING:
Step #4:
Re-attack

10. BALANCING:
Step #6:
Repeat

11. Why is there a 2?! DIATOMIC Di = 2 atom = atom Na + Cl2  NaCl
Draw the Lewis Structure for Cl2
DIATOMIC
Di = 2
atom = atom

12. TRICKS: Save lone elements for last
Group polyatomics for easier inventory
Typically saving oxygen and hydrogen for last is easier