1. Balancing Equations (pgs. 250-254)
Chemical Equations & Reactions
Balancing Equations (pgs )

2. WARMUP Decide whether the following equations are “balanced” or not.
Na + MgF NaF + Mg
Cu(NO3)2 + Na2CO CuCO3 + NaNO3
P4O10 (s) P4 (s) + 5O2 (g)

3. Balancing Steps Write the unbalanced formula equation.
Count atoms on each side.
Add coefficients to make #s equal.
Coefficient  subscript = # of atoms
4. Reduce coefficients to lowest possible ratio, if necessary.
5. Double check atom balance!!!

4. Helpful Tips Balance one element at a time.
Update all atom counts after adding a coefficient.
If an element appears more than once per side, balance it last.
Balance polyatomic ions as single units.
“1 SO4” instead of “1 S” and “4 O”
Balance H atoms and O atoms after atoms of all other elements have been balanced.

5. Practice
NH4NO3 + Ba3(PO4) Ba(NO3)2 + (NH4)3PO4

6. Practice
Aluminum acetate and magnesium sulfate react to form aluminum sulfate and magnesium acetate.

7. Balancing Example 2 Al + CuCl2  Cu + AlCl3 3 3 2
Aluminum and copper(II) chloride react to form copper and aluminum chloride. 2
Al CuCl2  Cu AlCl3 Al Cu Cl 3 3 2
2 
 2
 6
3 
6 
 3

8. Avoid Most Common Mistakes
writing incorrect chemical formulas for reactants or products
trying to balance an equation by changing subscripts