Kinetics Flashcards
How to identify the rate from a graph?
The gradient- Ea/RT
Maxwell-Boltzmann Distribution Curve properties
- area under curve does not change because total number of particles remain constant
- the most probable energy value is at the peak of the curve
Collision Theory-what must happen for a reaction to occur? (3things)
- Particles must collide
- They must collide with appropriate geometry
- Collide with sufficient energy
Activation energy
Minimum amount of energy required for a reaction to occur
How does Temperature affect the rate of reaction? Why?
Increase in temperature, increases rate of reaction
-more particles with sufficient energy to react thus more successful collisions
How does Concentration affect the rate of reaction?
Increasing concentration, increases rate of reaction
-increase number of particles in a given volume and so increases the chance of successful collision
How does Surface Area affect rate of reaction?
The smaller the particles the faster the reaction
How does catalysts affect the rate of reaction?
Presence of catalyst increases the rate of reaction
- provide an alternative pathway for the reaction with lower activation energy, and more reactants will possess lower Ea so rate increases
Rate Equation
Rate=k[A]x[B]y - A B= reactants!
What is the rate determining step?
The slowest step
What is Molecularity?
The number of particles reacting in the rate determining step of a reaction:
Unimolecular-1 species
Binolecular-2specieso
Arrhenius equation
K=Ae^(-Ea/RT)
A Arrhenius constant related to orientation of reactants
What are heterogeneous catalysts and how do they affect the rate reaction?
Catalyst in different phase than reactants- forms activated complex, weakening bonds and increasing collision-rate of reaction
What is an Activated complex?
An association of the reacting particles in which bonds are in the process of being broken and formed.
Either forms products or reverts to original reactants
Definition of Rate of Reaction?
The increase/decrease in the concentration of one of the products per unit time
