1. Physical Science Final Review #4
Reactions

2. Signs of a chemical reaction
Bubbles (gas forming)
Color change
Odor
Change in temperature
Light or sound

3. Reactions
Chemical reactions use energy to break bonds and to form new ones
Reactants are on the left side of the reaction
Products are on the right
Endothermic reactions
Need heat as a reactant
Exothermic reactions
Give off heat as a product
Catalysts speed up chemical reactions

4. Types of Reactions Synthesis Decomposition Single Replacement
Reactant + Reactant  Product
Decomposition
Reactant  Product + Product
Single Replacement
Element + Compound  New Element + New Compound
Double Replacement
Compound + Compound  New Compound + New Compound
Combustion
Reactant + O2  CO2 + H2O

5. Balancing Chemical Reactions
Write out all elements in the same order on the reactant side and product side
Count how many of each you have
Start with your biggest difference
Multiply your numbers. If it is a compound you must multiply the other element too.
Double check at the end to make sure everything is balance

6. Balancing Practice
____Al + ____Fe3N2  ____AlN + ____Fe