1. Types of Chemical Reactions

2. Five Types of Chemical Reactions
Remember…a chemical reaction is when one compound is changed into a totally different compound.
While there are millions of different types of reactions, they can all be classified into five general types.

3. Five Types of Chemical Reactions
The five types are:
Synthesis
Decomposition
Single Replacement
Double replacement
Combustion

4. Synthesis Reaction
A synthesis reaction takes place when two or more chemicals react to produce a single chemical.
The reactants can be either elements or molecules (the product is always a molecule).
A + B AB

5. Synthesis Reaction
Actual example:
2Na + Cl2 → 2NaCl

6. Practical use – the synthesis of nylon
Synthesis Reaction
Practical use – the synthesis of nylon
A key ingredient in toothbrushes, tents, carpet, clothes, guitar strings…

7. Decomposition Reaction
A decomposition reaction takes place when a molecule breaks down into two or more substances.
The reactant is always a molecule (never a single element).
AB A + B

8. Decomposition Reaction
An actual example:
H2CO3 → H2O + CO2

9. Decomposition Reaction
Practical use – car airbags
The rapid decomposition of sodium azide causes the bag to inflate with nitrogen gas in about seconds!

10. Single Replacement Reaction
A single replacement reaction takes place when one element takes the place of another element in a molecule.
The reactant side always consists of an element and a molecule.
A +BC B + AC

11. Single Replacement Reaction
An actual example:
2Na + 2H2O → 2NaOH + H2

12. Double Replacement Reaction
A double replacement takes place when two molecules exchange elements.
There are at least two molecules on both sides of the arrow.
AB + CD AD + BC

13. Double Replacement REaction
An actual example:
CaCO3 + 2HCl → CaCl2 + H2CO3

14. Combustion Reaction
A combustion reaction takes place when a hydrocarbon reacts rapidly with oxygen gas.
A hydrocarbon is a molecule made of carbon and hydrogen atoms.
The products are CO2 and H2O.
CH + O CO2 + H2O

15. Combustion Reaction
An actual example:
CH4 + 2O2 → CO2 + 2H2O

16. Practical use – internal combustion engine
Combustion Reaction
Practical use – internal combustion engine
Most forms of transportation use this type of engine.