1. Chemical Kinetics

2. Kinetics Rates of reactions How reactions happen
Series of steps from reactant to product

3. Rate of Reactions Particles must collide for chemical change to occur
Most reactions take several steps
Have an intermediate product
Example:
A + B  intermediate product
A + intermediate product  C
Net Equation: 2A + B  C

4. Factors affecting rate
1. Nature of reactants (intramolecular forces)
Ionic substances react faster than covalent bonds
Ionic bonds are simpler to separate

5. 2. Temperature Higher temperature = higher kinetic energy
Molecules collide more frequently
Rate increases

6. 3. Concentration More molecules = more likely to collide
Increases rate of reaction

7. 4. Pressure Volume is decreased, pressure is increased
Molecules closer together and collide easier
Increases rate of reaction

8. 5. Catalysts 6. Inhibitor Substance that speeds up the reaction rate
Doesn’t change itself in the process
Example: Enzymes
6. Inhibitor
Opposite of a catalyst
Slows the reaction rate

9. Reaction Mechanisms

10. Kinetics Rates of reactions How reactions happen
Series of steps from reactant to product

11. Rate of Reactions Particles must collide for chemical change to occur
Most reactions take several steps
Have an intermediate product (something made but used in another step)
Example:
A + B  intermediate product
A + intermediate product  C
Net Equation: 2A + B  C

12. Net reaction is the sum of the intermediate steps
If identical substances are on opposite sides, they cancel each other out
If identical substances are on the same side, they are added together
Some reactions have catalysts to speed them up
Catalyst present at beginning and end of reaction but does not show up in the net reaction

13. Graphing Reaction Mechanisms
When molecules react
Intermediate products are called the activated complex
Activation energy- minimum amount of energy needed to form intermediates

14. Potential Energy Diagrams
X axis- time (progress of reaction)
Y axis- potential energy
ΔH – enthalpy (heat of the reaction= energy absorbed or released)
ΔH = Energyproducts – Energy reactants

15. Endothermic reaction Products have more energy than reactants
Energy is absorbed to make the product
ΔH (enthalpy) is positive

16. Exothermic reaction Reactants have more energy than products
Energy is released to make the product
ΔH (enthalpy) is negative