1. Chapter 16
CHM 130
GCC

2. 16.1 Collision Theory
Molecules must hit/collide in order to react and make products
A successful collision results in reactant bonds breaking and/or product bonds forming
To increase the # of successful collisions:
you need more collisions.
you need enough energy, Ea, activation energy.
the molecules must be oriented correctly.

3. To Increase the Rate of Reaction
Increase [reactant], more reactants = more collisions
Increase temperature, molecules move faster = more collisions AND more energy
Add a catalyst which provides an alternate reaction pathway with lower Ea
Activation Energy, Ea, is the minimum energy needed to react (turn reactants to products)

4. 16.2 Energy Profiles
Transition state = in between reactants and products, the reactant bonds are ½ broken and product bonds ½ formed, so this is a very high energy and unstable species, exists less than a millisecond
DH = change in heat energy = product’s heat – reactant’s heat
Endothermic = reactants gain or absorb heat, heat is a reactant, heat enters the rxn
Reactants + Heat g Products
Exothermic = reactants lose or release heat, heat is a product, heat exits the rxn
Reactants g Products Heat

5. Exothermic, is DH + or -? -

6. Draw the energy profile for an endothermic reaction
Label the TS DH
Reactants
Products EA

7. Endothermic, is DH + or -? +

8. With Catalyst

9. Self Test
Page 477
Try 1-2, 10
Answers in Appendix J