1. Chemical Reactions
Types of Reactions

2. Reactions and Energy Exothermic – energy releasing rxns
Explosion, burning of fuel and rusting of iron
Endothermic – energy absorbing rxns
Cooking of food, electrolysis
Changes of state – adding or releasing energy is common

3. Reactions and Energy Law of Conservation of Energy
Energy can be converted from one form to another but the total quantity of energy is constant
Remember Bond Energy to help this theory make sense

4. Types of Reactions Synthesis Decomposition Single Displacement
Five main types of reactions
Synthesis
Decomposition
Single Displacement
Double Displacement
Combustion
One or more reactants combine to produce a new product
X + Y  XY

5. Types of Reactions Decomposition
A compound breaks down into two or more simpler compounds or elements.
XY  X + Y

6. Types of Reactions Single Displacement
One element takes the place (displaces) another element or compound.
A + BX  AX + B or AX + Y  AY + X
2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g) + thermal E

7. Types of Reactions A precipitate or water will be formed as products
Double Displacement
The cations of two different compounds exchange places, forming two new compounds
WX + YZ  WZ + YX
A precipitate or water will be formed as products

8. Reactions Involving Carbon
Organic Chemistry
Also all compounds containing carbon are organic (except CO2, CO and ionic carbonates)
Hydrocarbon
Used as fuels as reactions are exothermic
Crude oil and natural gas
When burned in a plentiful supply of oxygen it is known as complete combustion
Hydrocarbon + oxygen  carbon dioxide + water
Incomplete combustion = poor supply of oxygen
Still exothermic, but not as much heat given off
Carbon (soot) and carbon monoxide also given off