1. Warm-Up H2 + O2 → H2O 3 Br2 + 2Al → Al2Br6 2 CH4 + 3 O2 → CO2 + 4 H2O
Determine if the following are balanced, meaning the same number of atoms of each element on both sides.
H2 + O2 → H2O
3 Br2 + 2Al → Al2Br6
2 CH4 + 3 O2 → CO2 + 4 H2O
Ca(NO3)2 → Ca + 2 NO2 + O2

2. Follow along in your text Chapter 8 Section 1 Pages 260 – 266
Chemical Reactions
Follow along in your text Chapter 8 Section 1 Pages 260 – 266

3. Signs of a Chemical Reaction
Heat and/or light is released
Formation of a gas
Formation of a precipitate
Color change
Odor change
Also
Sound is produced
Reduction/increase in temperature
Absorb/emit electrical energy

4. Chemical Equations
A+B  C+D
REACTANTS
PRODUCTS

5. Law of Conservation of Mass
mass is neither created nor destroyed in a chemical reaction
total mass stays the same
atoms can only rearrange (Dalton’s)
4 H
2 O
4 H
2 O
36 g
4 g
32 g

6. Follow along in your text Chapter 8 Section 2 Pages 267- 274
Balancing Chemical Equations
Follow along in your text Chapter 8 Section 2 Pages

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

8. 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”

9. Balancing Example 2 Al + CuCl2  Cu + AlCl3 3 3 2 2  1 1 2 3 Al Cu Cl
Aluminum and copper(II) chloride react to form copper and aluminum chloride. 2
Al CuCl2  Cu AlCl3 3 3 2
2  Al Cu Cl
 2
 6
3 
6 
 3

10. Use your Ion Sheet to answer the following.
Closure
Use your Ion Sheet to answer the following.
Write the formulas for:
Iron (II) sulfide
Potassium carbonate
Write the names of:
AlPO4
(NH4)3P