1. Types of Chemical Reactions

2. Chemical Reactions
A chemical reaction has occurred when the starting substances (reactants) recombine to form ending substances (products).
The reactants will, most often, have different chemical and physical properties than the products.
Evidence of a chemical reaction can include (but is not limited to): bubbles, flames, change of color, change of state, precipitate.

3. Basic Types of Chemical Reactions
Synthesis (or combination)
Decomposition
Single Replacement
Double Replacement
Combustion

4. Synthesis (Combination)
Just like the name implies, a new substance is formed from two or more reactants.
The typical chemical equation will appear in the form of
A + B → AB
A and B can be single elements or molecules.
Example:
2H2 + O2 → 2H2O

5. Decomposition
Again, as the name implies, this type of reaction involves breaking reactants down into simpler substances.
In many ways, it is the opposite of a synthesis reaction.
The typical chemical equation will appear in the form of
AB → A + B
Example:
2KClO3 → 2KCl + 3O2

6. Single Replacement
In this type of reaction a single, reactive metal will replace a less reactive metal already bonded in an ionic compound.
The typical chemical will appear as
A + BC → B + AC
Example:
Cu + 2AgNO3 → 2Ag + Cu(NO3)2
You will need to use the activity series to determine whether this type of reaction will take place.

7. Activity Series
The only time a single replacement will take place is when the free metal is more reactive than the metal cation bonded in the ionic compound.
This reactivity is based on ionization energy. A metal with a lower ionization energy is more reactive than one with a higher ionization energy.
You will need to use the activity series to determine which metals are more reactive than others.

8. Activity Series Name Symbol Decreasing reactivity Lithium Li PotassiumK
Calcium Ca
Sodium Na
Magnesium Mg
Aluminum Al
Zinc Zn
Iron Fe
Lead Pb
(Hydrogen) H
Copper Cu
Mercury Hg
Silver Ag
A metal high on the table is more reactive and can replace a metal lower on the table. A metal lower on the table CANNOT replace a metal higher on the table.

9. Double Replacement Reactions
In this type of reaction, already bonded metal cations basically switch places with one another and bond with the already bonded nonmetal anions.
These reactions usually take place in aqueous solution.
The typical chemical equation will appear as
AB + CD → AD + CB
Example:
CaF2 + 2NaNO3 → Ca(NO3)2 + 2NaF

10. Double Replacement Reactions
Usually produce bubbles, a precipitate, or a molecular compound such as water.
In order to occur, one of the following is usually true.
One of the products is only slightly soluble and precipitates.
One of the products is a gas.
One product is a molecular compound such as water.

11. Predicting Precipitates
When a precipitate is formed, the precipitate can be predicted by using rules of solubility or a solubility table.
Remember, an insoluble substance will not dissolve in water and will therefore precipitate.
In a chemical reaction, a down arrow (↓) is usually written after the formula for the precipitate in order to indicate the precipitate.

12. Solubility Rules

13. Acid – Base Double Replacement
An acid, for now, is defined as a substance that produces a hydrogen ion in solution. We will recognize an acid as an ionic compound that starts with H.
Example: HCl, H2SO4
A base, for now, is defined as a substance that produces a hydroxide ion in solution. We will recognize a base as an ionic compound that ends with –OH.
Example: NaOH, Ca(OH)2

14. Acid – Base D.R. Reaction
When an acid and a base react, in a double replacement reaction, the products formed will be an ionic compound (salt) and water.
Example:
2NaOH + H2SO4 → Na2SO4 + 2H2O
base
Ionic salt
water
acid

15. Combustion Reaction
In a combustion reaction, a hydrocarbon burns in oxygen. The products formed are always carbon dioxide and water.
The typical format for this reaction is
CxHy + O2 → CO2 + H2O
Example:
CH4 + 2O2 → CO2 + 2H2O

16. Try These Worksheets!
ervices/TRIO/Types_of_reactions_worksheet.pdf
eet4.pdf
eet2.pdf
eet3.pdf
From this link, choose reaction products worksheet, six types of reactions, or double displacement reactions