1. Types of Reactions There are 5 types of reactions Combination
Decomposition
Single Displacement
Double Displacement
Combustion

2. Combination Reactions
Combination reactions have two or more reactants and only one product
A + B  AB

3. Decomposition Reactions
Decomposition reactions have only one reactant which breaks down into two or more products
AB  A + B

4. Single Displacement Reactions
In a single displacement reaction, an element replaces the atoms of a second element in a compound
AB + D  AD + B
AB + C  CB + A

5. Double Displacement Reactions
Remember, these involve the exchange of positive ions (or negative ions) between two compounds
AB + CD  AD + CB

6. Combustion
When an organic compounds reacts with oxygen to produce water and either CO or CO2
Complete combustion always ends with CO2 and H2O
Incomplete combustion always ends with CO and H2O

7. Combination Reactions
When two nonmetals react, or a transition metal reacts with a nonmetal, more than one product is often possible
With two nonmetals it is hard to predict the product
With the transition metal reacts it depends on the charge being used

8. Combination Reactions
Example
Fe(s) + S(s) 
Fe(s) + S(s)  FeS(s) iron (II) sulfide
Fe(s) + S(s)  Fe2S3(s) iron (III) sulfide
Make sure to balance when finished

9. Combination Reactions
When a metal from one of the first two groups reacts with a nonmetal there is only one possible product
Use the oxidation number (charge) to determine the final compound

10. Combination Reactions
Example
K(s) + Cl2(g) 
K+ and Cl-1 so KCl
K(s) + Cl2(g)  KCl(s)
Make sure to balance

11. Decomposition Reactions
Remember, a decomposition reaction has only one reactant which breaks down into two or more products
AB  A + B

12. Decomposition Reactions
The difficulty with decomposition reactions is the products can be any combination of elements or compounds found in the reactant
It is usually very difficult to predict decomposition products

13. Decomposition Reactions
Example
H2O
H2O  H2 + O2
Don’t forget to balance!

14. Decomposition Reactions
Example
Mercury (II) oxide(s)
HgO 
HgO  Hg + O2(g)
Don’t forget to balance!

15. Single Displacement Reactions
Remember, a single displacement reaction is when an element replaces the atoms of a second element in a compound
AB + D  AD + B
AB + C  CB + A

16. Single Displacement Reactions
When a metal replaces another metal in a compound a new compound is formed
When forming a new compound, make sure the charges cancel out in the new compound

17. Single Displacement Reactions
“Single Switch”
Example
Mg + Zn(NO3)2 
Mg+2 and NO3-1 so it forms Mg(NO3)2
Mg + Zn(NO3)2  Zn + Mg(NO3)2
Make sure to balance!

18. Double Displacement Reactions
“Double Switch”
Remember, these involve the exchange of metals (positive ions) and nonmetals (negative ions) between two compounds
AB + CD  AD + CB

19. Double Displacement Reactions
Example
BaCl2 + K2CO3 
First identify the ions before swaping
Ba+2 Cl K+ CO3-2
BaCl2 + K2CO3  BaCO3 + KCl
Don’t forget to balance

20. Combustion
When an organic compounds reacts with oxygen to produce water and either CO or CO2
Complete combustion always ends with CO2 and H2O