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Topic 13 Rates of Reaction

 

INTRODUCTION TO KINETICS
Chemical kinetics
Importance of the study of chemical kinetics
Application to industrial processes
Application to everyday processes
REACTION RATES
Description
Factors affecting reaction rate
The concentration of reactants
The temperature at which the reaction occurs
The presence of a catalyst
The surface area of a solid or liquid reactant or catalyst
Definition
Verbal definition
Mathematical definition
Two approaches to describing reaction rate
Average rate
Instantaneous rate
Graphical representations of reaction rate
Relating rate of disappearance of a reactant and rate of appearance of a product from the balanced equation
Determining the average reaction rate from concentration measurements at specific times
DEPENDENCE OF REACTION RATE ON CONCENTRATION
Rate constant
Definition
Symbol
Characteristics
Rate law
Definition
Form
Reaction order
For a reactant (or catalyst)
For a reaction
Examples
Determining the rate law from initial concentrations and initial rates
Procedure
Examples
CHANGES OF CONCENTRATION WITH TIME
The use for a rate law
The use for a concentration-time law
Concentration-time laws for first order and second order reactions
First order reactions:  concentration-time equation
Second order reactions:  concentration-time equation
Using graphing to determine the order of a reaction
An alternative to the approach of running multiple experiments
Approach
First order assumption
Second order assumption
COLLISION THEORY
Reactions involve collisions between particles
Involve a transfer of atoms
Happens when the particles collide
More collisions mean the reaction will go faster
Collisions alone are not a complete explanation
Statistics
If every binary collision led to a product, then every reaction would be over almost instantaneously
Energy considerations are also a part of the explanation
Kinetic energy can be converted to vibrational energy in collisions
When the translational kinetic energy of the colliding particles is high enough
When the translational kinetic energy is too small
Collision theory and an energy description of bond breaking and forming.
Activation energy 
Activated complex
Potential energy profiles
Collision theory and an explanation of factors affecting reaction rate
The effect of increasing temperature
The effect of increasing concentration
The effect of increasing the surface area of a solid or liquid reactant
The presence of a catalyst
The relationship among activation energy, temperature, frequency of collisions, and the rate law constant
Arrhenius equation
The comparative Arrhenius equation
REACTION MECHANISMS
Definition and description of a reaction mechanism
Definition and description of elementary steps
Definition and description of reaction intermediate
Definition and description of molecularity
Writing the overall balanced equation from the mechanism
Rate laws and elementary steps
Rate laws for elementary steps with each of the three molecularities
Writing rate laws for elementary steps
Rate law and mechanisms
Rate law and single step mechanisms
Rate law and multi-step mechanisms
Determining the rate-determining step from the rate law
CATALYSIS
Importance of catalysts
Industry
Biologically
Nature of catalysts
Catalysts increase the rate of reaction
Catalysts increase the rate of both the forward and the reverse reaction
Catalysts do not undergo permanent chemical change in the reaction they catalyze
Catalysts work by lowering the activation energy for the reaction - both forward and reverse
Inhibitor
Homogeneous catalysis
Heterogeneous catalysis
Enzyme catalysis