1. The 5 Basic Classifications
Chemical Reactions
The 5 Basic Classifications

2. SYNTHESIS
A reaction in which two or more reactants yield a single product.
Also called composition or combination
General Equation
A + B  AB
EX: 2 Li + Se ---> Li2Se

3. Decomposition Reaction
One Reactant Breaking Down into two or more products
General Equation
AB ---> A + B
Example:
2 HgO  2 Hg + O2

4. What Is Combustion? 2Mg(s) + O2(g) 2MgO(s)
One or more reactants combine with oxygen releasing heat or light
Any combustion reaction must include the reactant oxygen, O2
General Equation:
A + O2  AO
Example:
2Mg(s) + O2(g) MgO(s)

5. Single Replacement 2 Na + 2 HOH ----> 2 NaOH + H2 A + BX  AX + B
Sometimes called Displacement
One element replaces a similar element in a compound
A + BX  AX + B
2 Na + 2 HOH ----> 2 NaOH + H2

6. Double Replacement
Reaction that has the interchanging of two ions from two different compounds.
general form:
AB + CD----> AD + CB
Example:
Pb(NO3)2 + 2 KI ----> PbI KNO3

7. Double Replacement
Equation consists of two reactants that have both a cation and anion.
During a reaction the cations (or anions) switch places.
The products usually consist of a precipitate.

8. Reaction Checklist 1) Is O2 a reactant? (combustion)
2) One product? (synthesis)
3) One reactant? (decomposition)
4) Is an element being replaced? (single)
5) 2 switches? (double)