1. Chapter 6 – 4 Chemical Reactions
Rates of Change

2. Rate of Change Chemical reactions occur at different rates or speeds.
Explosion of nitroglycerine
Fast
Burning of carbon in charcoal
Slow

3. Reaction Rate Most reactions go faster at higher temperatures
Faster moving particles collide more often = more chance for a reaction

4. Bread in freezer vs Bread on counter

6. Rate of Reaction
A large surface area speeds up reactions

7. Rate of Reaction Concentrated solutions react faster
A drop of bleach vs a bottle of bleach

8. Rate of Reaction Reactions are faster at higher pressure
Less space = more collisions

9. Rate of Reaction Massive molecules react slower
The bigger it is the slower it moves = less collisions

10. Catalysts Catalyst – substance that changes the rate of a reaction
Speed up or slow down
Inhibitor – slows down

11. Enzymes
Enzyme – type of protein that speeds up metabolic reactions in plants and animals
Substrate – a molecule upon which an enzyme acts

12. Chemical Equilibrium
Chemical Equilibrium – a state of balance in which the rate of a forward reaction equals the rate of the reverse reaction
A balanced state
Carbonated drinks

13. Chemical Equilibrium
Molecules of CO2 are constantly moving in and out of the solution
Football players moving off and on field but always 11 on the field

14. Le Chatelier’s Principle
If a change is made to a system in chemical equilibrium, the equilibrium shifts to oppose the change until a new equilibrium is reached.
Predicts changes in equilibrium.

15. Le Chatelier’s Principle
Effects of change:
Temperature – increase favors reaction
Pressure – increase favors reaction
Concentration – increase favors reaction

16. P.212 #1-3, 6
P. 197 #1,4,6,7
P.189 #1-4