1. How to identify and classify reactions
What will I Learn today?
How to identify and classify reactions
Review: Evidence of a reaction
Color change
Precipitate (Solid forms)
Gas produced (Bubbles form)
Temperature change
Endothermic: heat is absorbed: Feels Cold
Exothermic: heat is released: Feels Warm

2. CH4 + O2 CO2 + H20 Chemical Equation reacts with yields and
reactants products

3. 5 ways to Classify Reactions
1. Synthesis Reactions (Combining)
A synthesis reaction is one in which a compound forms from simpler materials.
This is a redox reaction
A + B AB
EX: C(s) + O2(g)  CO2(g) +

4. AB A + B 2. Decomposition Reactions (breaking apart)
A decomposition reaction occurs when a compound is broken down into simpler substances.
This is a redox reaction
AB A + B
EX: 2H2O(l)  2H2(g) + O2(g) +

5. A + BC B + AC 3. Single displacement One ion is exchanged with another
This is a redox reaction
A + BC B + AC
EX: Zn(s) + 2HCl(aq) H2 (g) + ZnCl2 (aq) + +

6. 4. Double Displacement (or) replacement
2 ions are exchanged
Not usually a redox
AB + CD AD + CB
EX: *HCl (aq) + KOH(aq) HOH(l) + KCl(aq)
* recall starting with an H makes it an acid creates products of water and a salt + +

7. 5. Combustion Reaction with Oxygen, gives off heat and energy
Usually the product is CO2 and H2O
Ex. CH CO2 + 2H2O

8. Other Ways to Classify Reactions
Summary