1. Chemical Reactions
How matter changes

2. What is a chemical reaction?
Chemical Reactions occur when there is a CHANGE in the CHEMICAL MAKEUP of a sample
Examples of chemical reactions:
Burning gasoline
Iron oxidizing into rust
Baking soda and vinegar
Examples of NOT chemical reactions (physical changes):
Water boiling and turning into steam
Salt dissolving into water
Mixing together red paint and blue paint to make purple paint

3. Identifying a chemical reaction
The only sure-fire, 100% accurate way to identify a chemical reaction is to know what CHEMICALS YOU START WITH AND END WITH. If any chemicals changed then it’s a chemical reaction.
Examples:
C8H18 + O2 → CO2 + H2O
Fe + O2 → Fe2O3
CH3COOH + NaHCO3 → CH3COONa + H2O + CO2

4. Things to Look For (If you don’t know the chemicals)
Bubbles of gas form
Precipitates (insoluble solids) form
Color change
Temperature change
Light emitted
Volume change
Conductivity change
Melting/boiling point change
Smell or taste change (not recommended)
Change in any distinctive chemical/physical property

5. Synthesis Decomposition Single Replacement Double Replacement
5 Types of Reactions
Synthesis
Decomposition
Single Replacement
Double Replacement
Combustion

6. Brought to you by:

7. Synthesis
Two things coming together
A + B  AB + 

8. Decomposition
One thing coming apart
AB  A + B  +

9. AB + C  AC + B Or AB + C  CB + A Single Replacement
One part is switched
AB + C  AC + B Or
AB + C  CB + A

10. Example +  +  + +

11. Double Replacement
Both things switch
AB + CD  AD + CB +  +

12. Combustion
A hydrocarbon burns in oxygen
CxHy + O2  CO2 + H2O

13. Classifying Reactions
Identify the following reactions:

14. The Law of the Conservation of Mass

15. The Law of the Conservation of Mass
Mass cannot be created or destroyed
Can be represented in chemical reactions
Use coefficients to balance reactions in accordance to the law of the conservation of mass

16. The Law of the Conservation of Mass

17. Reactants
Products 5 4 3

18. Practice Keep track of your numbers Both sides must be equal
You can only change coefficients!

19. Stoichiometry Stoichiometry tells the future
Uses mole relationships from a balanced chemical equation to predict the amount of reactants needed to produce a certain amount of product.
The amount of product calculated from a stoichiometric equation is called the theoretical yield
A limiting reactant must be calculated first