1. Chemical Reactions

2. Chemical Reaction…

3. Not a Chemical Reaction…

4. What is a Chemical Reaction?
A process in which new substances with new chemical and/or physical properties are formed.
A burning piece of paper (Chemical Reaction):
paper  ashes, water vapor, and carbon dioxide
Dissolving salt in water (No Reaction):
Salt Water → Salt Water

5. Parts of a Chemical Equation
Na+ Cl → NaCl
sodium
and
chlorine
yields
sodium chloride
Reactants
The substances that you start with. In this case:
Sodium and Chlorine
“Yields”
This arrow tells you that the reactants become the products through a chemical reaction.
Products
The substances you end with. In this case:
Sodium Chloride

6. Mg + O2 → MgO H2O → H2 + O2 C4H10 + O2→CO2 + H2O Chemical Equations
magnesium
and
oxygen
yields
magnesium oxide
H2O → H2 + O2
water
yields
hydrogen
and
oxygen
C4H10 + O2→CO2 + H2O
butane
and
oxygen
yields
carbon dioxide
and
water

7. Types of Chemical Reactions Type 1: Synthesis
In a synthesis reaction, two (or more) simple substances form a more complex substance.
Synthesis: Two Become One
A + B → AB

8. Synthesis Example Na + Cl → NaCl
sodium and chlorine yields sodium chloride

9. Types of Chemical Reactions Type 2: Decomposition
In a decomposition reaction, a complex substance is broken down into two (or more) simpler substances.
Decomposition: One Becomes Two
AB → A + B

10. Decomposition Example
H2O2 → H2O + O2
hydrogen peroxide yields water and oxygen

11. Types of Chemical Reactions Type 3: Single Replacement Reaction
In a single replacement reaction, a single element replaces another element in a compound.
Single Replacement: Start with one compound, end with a different compound.

12. A BC B AC
Single Replacement Reaction

13. Single Replacement Example
Zn HCl → H2 + ZnCl2
zinc and hydrochloric acid yields hydrogen and zinc chloride

14. Types of Chemical Reactions Type 4: Double Replacement Reaction
In a double replacement reaction, elements from two compounds switch places and form two new compounds.
Double Replacement: Start with two compounds, end with two different compounds.

15. AB CD CB AD
Double Replacement Reaction