1. How Fast Does the Reaction Go?
Reaction Rate
How Fast Does the Reaction Go?

2. Collision Theory
In order to react molecules and atoms must touch each other.
They must hit each other hard enough to react.
Must break bonds
Anything that increases how often and how hard will make the reaction faster.

3. Energy
Reactants
Products
Reaction coordinate

4. Activation Energy - Minimum energy to make the reaction happen – how hard
Reactants
Products
Reaction coordinate

5. Activated Complex or Transition State
Energy
Reactants
Products
Reaction coordinate

6. Activation Energy Low activation energy
Lots of collision are hard enough
fast reaction
High Activation energy
Few collisions hard enough
Slow reaction

7. Indicators of a Chemical Reaction
Gas produced (bubbles)
Temperature change (gets hot or cold)
Color change
Precipitate formed
Light given off

8. Reaction Rate How fast a reaction happens
reactions depend on collision frequency and efficiency

9. Factors that Affect Rate
1. Reactant Nature
what the reactant reacts with
Metal Reactivity
Mg in HCl vs Cu in same solution

10. Ex. Alka Seltzer balloon race
2. Temperature
more energy in the particles causes more collisions and more energy to make the reaction occur
Ex. Alka Seltzer balloon race

11. Ex. Concentrated vs. dilute acid
3. Concentration
more particles to react with; causes a faster reaction because of more collisions
Ex. Concentrated vs. dilute acid

12. 4. Catalysts
catalyst - a substance that changes the reaction rate without being used up
Lowers the activation energy - allows the to reaction happen more easily.

13. rxn occurs where two surfaces are in contact
5. Surface Area
rxn occurs where two surfaces are in contact
Ex. Sugar (cube vs. powdered)

14. Endothermic Reactions
Energy is used to begin a reaction
Products have higher energy than reactants
Absorbs heat from surroundings
Ice melting
Water evaporating

15. Exothermic Reactions Gives off energy during a reaction
Reactants have more energy than products
Gives off heat
Ice freezing
Water condensing