Kinetcs Flashcards
Methods for measuring rate of reaction
Volume of gas
Colorimity
Titration
Electrical conductivity
How is order of reaction measured
Experimentally
Change the conc of reactants while leaving other reactants in large excess
What does the rate equation tell us
Relationship between conc of a reactant and rate of reaction
What is the rate determining step
The slowest step of the reaction for a multi- step reaction
Determines to overall rate
Why would a reactant not be involved in the rate equation
Must be involved in steps after the rate determining step
OR
Must be involved in more than one step
What are heterogenous catalysts
Catalysts in a different phase to reactants
How do heterogeneous catalysts work
Adsorption- reactant absorbed onto surface of catalyst
Reaction- molecules held in place to react
Desorption- product molecules leave the surface
What are homogeneous catalysts
Catalysts in the same phase as reactants
Define activation energy
Energy required for a collision to be successful
Define catalyst
A substance used to lower the activation energy by providing alternative reaction pathway
Stages of catalysts
Adsorption
Reaction
Desorption
What occurs in adsorption
Reactant is absorbed onto surface of catalyst
Holds molecule in correct orientation
Weakens bonds in reactants
What occurs in the reaction stage of a catalyst
Molecules held in position so they can react
What occurs in the desorption stage of a catalyst
Product molecules leave the surface
Potential issues with catalysts
Adsorption too weak/strong
Catalyst poisoning- other molecules adsorb onto surface and block active sites
