1. Chemical Reactions

2. Chemical Change New substance is formed
Compare original substance Reactant with the new substance Product
Reactant + Reactant  Products

3. Reactants Products
Can be written as Carbon plus oxygen gas yields carbon dioxide

4. You cant get something from nothing
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction.
What you start with you must end up with
No POOF! Its gone type of stuff.

5. types of chemical reactions
synthesis reactions
decomposition reactions
single-replacement reactions
double-replacement reactions
combustion reactions.

6. Synthesis reactions A + B  AB 2 or more reactants 1 product
Think Dating!
Example from this year:
H2+ O2 H2O

7. Decomposition One Reactant Two or more products AB A + B
Think Breakup
Example from this year
H2O  H2 + O2
H2O2  H2O + O2

8. Single Replacement A + BC AC + B
An element will replace another element in a compound
The old “switcheroo” Single girl goes in and takes guy from another girl
Example from this year
Zn + HCl ZnCl2 + H2

9. Double Replacement AB + CD AD + CB
Compounds recombine into different compounds
Think two dates where they swap partners

10. Combustion
Oxygen burning with a hydrocarbon produces water and carbon dioxide
O2 + CHx  CO2 + H2O

11. Balancing Reactions
In order to show that mass is conserved during a reaction, a chemical equation must be balanced.

12. Balancing rules
balance a chemical equation by changing the coefficients.
When you change a coefficient, you change the amount of that reactant or product represented in the chemical equation.
As you balance equations, you should never change the subscripts in a formula. Changing the formula changes the identity of that reactant or product.

14. Follow this series of questions
Follow this series of questions. When you can answer "yes" to a question, then stop!
1)  Does your reaction have oxygen as one of its reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction
2)  Does your reaction have two (or more) chemicals combining to form one chemical product? If yes, then it's a synthesis reaction
3)  Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction
4)  Does your reaction have reactants that contain only one element and products that contain only one element? If yes, then it's a single displacement reaction
5)  If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction

15. Exothermic reaction
a chemical reaction that releases energy to its surroundings
Released as heat and light

16. Endothermic reaction
a chemical reaction that absorbs energy from its surroundings
Add heat to get the reaction to occur

17. Reaction Rates
the rate at which reactants change into products over time

18. Factors that affect Reaction Rates
Temperature
surface area
Concentration
Stirring
catalysts.