1. Types of Chemical Reactions
(there are a lot, millions of different reactions).
Scientists classify reactions into several general categories to allow predictions to be made.
5 Major Types of Reactions
Iron + Sulfur Reaction
Elephant Toothpaste

2. 1. Synthesis Reaction Direct combination
two or more simpler substances combine chemically to form a more complex substance.
general formula: A + B  AB

3. 1. Synthesis Reaction - Examples
Na Cl  NaCl
(sodium) (chlorine)  (sodium chloride) [table salt]
Synthesis Reaction

4. 2. Decomposition
a more complex substance breaks down chemically to a simpler substance.
general formula: AB  A + B

5. 2. Decomposition - Examples
2H20  2H O2
(water)  (hydrogen gas) (oxygen gas)
Decomposition Reaction

6. 3. Single Replacement Displacement
an element will replace another element in a compound, almost always occurs in a solution.
general formula: A + BX  B + AX

7. 3. Single Replacement - Examples
Fe + CuSO4  Cu + FeSO4
(iron) (copper sulfate)  (copper) (iron (II) sulfate)
Single Replacement Reaction

8. 4. Double Replacement Displacement
the anions and cations in two compounds (in solution) change partners.
General formula: AX + BY  AY + BX

9. 4. Double Replacement - Examples
AgNO3(aq) + NaCl(aq)  AgCl + NaNO3
(silver nitrate) (sodium chloride)  (silver chloride) (sodium nitrate)
NaCl KF  NaF KCl
(sodium chloride) (potassium fluoride)  (sodium fluoride) (potassium chloride)
Double Replacement Reaction

10. 5. Combustion
Burning
Combustion: rapid reaction of a substance with oxygen.
General Formula: CxHy + O2  CO2 + H2O

11. 5. Combustion - Examples C3H8 + 5O2  3CO2 + 4H2O Combustion Reaction
(propane) (oxygen gas)  (carbon dioxide) (water)
Combustion Reaction