1. Kinetics

2. Kinetics Collision Theory
is the branch of chemistry that is concerned with the speed of a chemical reactions( reaction rates) and the way in which reactions occur (reaction mechanisms)
Collision Theory
• Collisions between particles can produce a reaction if both the spatial orientation and energy of the colliding particles are conducive to a reaction.
• Reactants must collide in order for a reaction to take place
• reactions involve breaking existing bonds and the formation of new bonds

3. Factors that Effect Reaction Rates
Pressure
Only on a gas
has no effect on a
solid or liquid
increase pressure on a gas increases concentration-- increasing rate
Nature of the reactants
• bond type
• ionic react more quickly than covalent- because they have few bonds to break and rearrange.
2Fe + O2 = 2FeO is slow
Ag NO3 + NaCl is quick
Surface area
As the surface area increases
the number of collisions
increases, therefore…
the rate of the reaction will
increase
Factors that Effect Reaction Rates
Concentration
As the concentration [ ]
of the reactants increases
-- the number of collisions
increases and the rate of
the reaction generally
increases
Temperature
Increasing temperature
increases the average
kinetic energy of the
particles
-- increasing the number of
effective collisions--
-- increasing the rate of a
reaction
Best way to speed up a
Catalyst
a catalyst lowers the
activation energy
therefore increasing the
speed of the reaction

4. Q = mc∆T Calorimetry is the study of heat and heat transfer
Calorimeter
an instrument used to
indirectly measure the amount of heat released or absorbed by a substance
mass
mass of the
substance
measured in grams
most common water
1ml water = 1g of water
specific heat
amount of energy
needed to raise 1g
1˚ C
water 4.18J/g˚C
4.18 J/gK
Change in
temperature
Final T- Initial T
˚C or K
determine the
sign of Q
Joule
unit of energy
measures the amount of
energy released or
absorbed
- Q = exothermic
+ Q = endothermic
Types of energy:
-chemical (bonds breaking/forming)
-mechanical- movement, machine
-electrical- transport of e-’s
-thermal- heat transfer
-nuclear- mass to energy

5. Conservation of Energy
Heat Lost = Heat gained
the amount of heat lost by one substance equals the amount heat gained by the other substance.
Heat moves from Hot to cold
Heat of Fusion
Heat of Vaporization
During a
Phase Change
remember no change in temp.
amount of heat needed to change one gram of solid to one gram of liquid at its melting pt.
amount of heat needed to change one gram liquid to one gram of gas at boiling pt.
Heat of vaporization for water 2260J/g
at 100˚C and 1 atm
Heat of fusion for solid water is 334 J/g
at 0˚C and 1 atm
q = mHf
q = mHv

6. Exothermic Endothermic Potential Energy Diagrams Activation Energy
Increasing P.E.
Time of rxn
Act. complex
React.
Product
Activation Energy
the amount of energy needed to form an activated complex
a reaction must achieve this point in order to occur 4 2 5 3 6 1
Catalyst
a substance that alters the speed of a reaction without being permanently changed
-lower the activation energy
1 = Potential Energy (PE) of the reactants
2 = PE of the activated complex
Activated
Complex
the temporary intermediate product in a chemical reaction
3 = PE of the products
4 = Activation energy of the forward reaction
(left to right for reading diagram)
5 = Activation energy of the reverse reaction
(read right to left in diagram)
6 = Heat of reaction –ENTHALPY
∆ H = PE products - PE reactants

7. Low energy (exo) and Very messy (high entropy)
Enthalpy
(heat = H )
Amount of heat released or absorbed by a reaction
+ Q(H) = endo
- Q(H) = exo
Hf = heat of formation
energy for one mole
Entropy
(disorder = S)
“messy”
measure of disorder
When –
+ S = entropy increases
- S = entropy decreases
Dependent on
1. # of molecules
2. State of matter
In nature---
Low energy (exo) and Very messy (high entropy)
Spontaneous Reactions
Once a reaction is started
No more energy is required to
Keep it going
G is spontaneous
Predicating spontaneousness
G = spontaneous
+ G = not spontaneous