Types of Chemical Rxts
Two ways to classify:
1. Temperature
2. Type
Temperature
1.
2.
Endothermic Rxts: heat is added to
reactants; heat is absorbed
Exothermic Rxts: heat is added to
products; heat is given off
Types
1.
2.
3.
4.
5.
6.
7.
Synthesis (combination)
Decomposition
Single Displacement (replacement)
Double Displacement (replacement)
Combustion
Neutralization (acid/base)
Redox Reactions
(oxidation/reduction)
1. Synthesis Reactions
Two or more reactants combine to
form one product
 A + B → AB
Ex: 2K + Cl2 → 2KCl
S + O2 → SO2
2S + 3O2 → 2SO3
CaO + H2O → Ca(OH)2

2. Decomposition Rxts
One reactant breaks down into two or
more products
 AB → A + B
Ex: CaCO3 → CaO + CO2
2HgO → 2Hg + O2

3. Single Displacement
A single element displaces a similar
element in a compound to form a new
single element and a new compound
 A + BC → AC + B
or
 A + BC → BA + C
Ex: Mg + Zn(NO3)2 → Mg(NO3)2 + Zn
Cl2 + 2NaBr → 2NaCl + Br2

(Continued)

•
Li
K
Ca
Na
Mg
Al
Zn
Fe
Pb
H
Cu
Hg
Ag
Reactivity of Elements (See handouts)
Elements can kick out any element below it on the table. Elements on top are
most reactive
F
Cl
Br
I
At
Mg + LiNO3 → No reaction
4. Double Displacement
An exchange of positive ions between
two reacting compounds
 AB + CD → CB + AD
 AB + CD → AD + CB
Ex: Na2S + Cd(NO3)2 → 2NaNO3 + CdS

5. Combustion
An element or compound reacts with
oxygen gas producing carbon dioxide,
water, and energy.
A + __O2 → __ CO2 + __H2O + energy
Ex. 2C6H6 + 15O2 → 12CO2 + 6H2O
