1. Balancing Equations

2. Balancing Equations Recall: Law of Conservation of Matter:
Matter can not be created nor destroyed
Matter can only be rearranged
Ex: The burning of aluminum to produce aluminum oxide
Ex: Al + O2  Al2O3
?? Where did the extra Al & O come from??
We must balance the equation

3. The numbers in equations
SUBSCRIPTS- These numbers tell you how many atoms of each element are in the compound.
*********** You CAN NOT change the subscripts in a formula!!!!!
COEFFICIENTS- The BIG numbers in front of the chemical formula. These numbers represent the number of compounds in a reaction.
************ You CAN change the coefficient in a formula!!!!
Ex: 4 H2O =
= 4 water molecules
= 8 Hydrogen & 4 Oxygen Atoms (=Coefficent x subscript)

4. Steps for Balancing Equations
Count the # of atoms on each side of rxn
a) Make a list of each type of atom for both sides, keep the order the same!!!
If you have polyatomic ions on both side of the rxn treat them as one unit
Balance the equation by changing ONLY the coefficients
√ your math to see if all elements/ polyatomics are balanced
√ to see if the coefficients can be reduced

5. Ex: 1 (Type?______________)
___Al + ____O2  ____Al2O3

6. Ex: 2 (Type?______________)
____ C3H8 + ____ O2  ____CO2 + ____H20

7. Ex: 3 (Type?______________)
__ (NH4)3PO4 + __ Pb(NO3)4  __ Pb3(PO4)4 + __ NH4NO3

8. Ex: 4 (Type?______________)
____ Al + ____ Fe2N2  ____ AlN + ____Fe

9. Ex: 5 (Type?______________)
____ C7H17 + ____O2  ____ CO2 + ____ H2O
* Hint: when you get stuck on these, double your carbons (and everything else) wherever you get stuck. Trust Me 

10. Snowman Challenge Rules
From the snowmen choose 1 question at a time.
If you pick it, you must solve it!!
Copy the question into notebook, add spaces for balancing. Must show work!!!
You must get each question right before choosing a new question.
Do 10 questions for full credit, up to 15 for extra credit