1. Chemical Reactions: Types, Energy, and Rates
(selected)

2. Types of Chemical Reactions
19.2

3. A combustion reaction occurs when a substance reacts with oxygen to produce energy in the form of heat and light.

4. Synthesis Reaction – reaction where two or more substances combine to form another substance
A + B → AB
2H2 + O2 → 2H2O

5. Decomposition Reaction – reaction where one substance breaks down or decomposes into two or more simpler substances
AB → A + B
2H2O → 2H2 + O2

6. A + BC → AC + B A + BC → AB + C Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
Single-Displacement Reaction – reaction in which one element replaces another in a compound
A + BC → AC + B
A + BC → AB + C Or
Cu + 2AgNO3 → Cu(NO3) Ag

7. AB + CD → AD + CB Ba(NO3)2 + K2SO4 → BaSO4 + 2KNO3
Double -Displacement Reaction – reaction that results in a precipitate, water, or gas when a positive ion of one compound swaps with another positive ion of another compound
AB + CD → AD + CB
Ba(NO3)2 + K2SO4 → BaSO4 + 2KNO3

8. Oxidation-Reduction Reactions
Chemists use the term oxidation to describe the loss of electrons and the term reduction to describe the gain of electrons.

9. Chemical Reactions and Energy
19.3

10. Chemical reactions involve energy exchange Exothermic Reactions
Reaction in which energy is released in form of heat
Ex: burning wood, exploding fireworks

11. Reaction in which heat energy is absorbed
 Endothermic Reactions
Reaction in which heat energy is absorbed
Ex: chemical ice packs, photosynthesis

12. Thermal Energy Absorbed
This graph shows how energy is absorbed during chemical reactions.

13. Reaction Rates
19.4

14. Reaction Rates Increased collisions lead to increased reaction rate.
The reaction rate can be increased by:
increasing reaction temperature or pressure
increasing reactant concentration or surface area
decreasing reaction volume (for reactions between gases)

15. Catalyst – speeds up a chemical reaction without itself being permanently changed

16. Inhibitor – prevents or slows a chemical reaction or interferes with the catalyst