1. Ch. 19 Reaction Rates and Equilibrium

2. Section 19.1 Reactions can occur:
Very Fast- like a firecracker
Very Slow- turning a dead plant into coal
Moderately- Food spoiling
Reaction rate – is the speed of change in a reaction within any interval of time.

3. Collision Theory: reactions occur when atoms, ions, or molecules collide to form products. Particles must have enough Kinetic Energy (movement).
Molecules much touch (or collide) to react
Only a small fraction of collisions produce a reactions because some particles lack the kinetic energy to react.
When the molecules don’t have the kinetic energy to react, they bounce off each other unchanged

4. Activation Energy- minimum amount of energy particles must have to react.
Activation Complex (Transition State)- moment when reactants change into products

5. Factors Affecting Reaction Rates
Temperature
Increase temperature speeds up reactions because particles are moving around faster ( ↑KE)
Decrease temperature slows down reactions because particles slow down (↓KE)
Concentration
More particles = more collisions

6. Factors Affecting Reaction Rate
Particle Size
Increase surface area = more exposure and collisions
Therefore, reaction rate is increased.
Grinding into smaller pieces increases surface area.
Catalyst
Substance that helps a reaction get started or move along faster
Catalysts are not used up or part of the reaction
Written above arrow in reactions

7. Ex:
Inhibitor (opposite of a catalyst): interferes with action of a catalyst aka: blocker