Kinetics I Flashcards
what is activation energy?
the minimum amount of energy for a reaction to occur
so bonds can break
what needs to happen for a reaction to take place?
-particles must collide in right direction
-particles must have a minimum amount of KE
how does concentration affect rate of reaction?
more particles of reactant in a given volume=more frequent collisions=higher chance of reacting
how does temperature affect rate of reaction?
more KE=more frequent collisions=higher chance of particles reacting
what are the economic benefits of catalysts?
-lower temperature=less money spent=less CO2 produced
-makes products more useful by changing its properties
examples of economic benefits in industry?
iron catalyst in ammonia production:
-without iron temp would have to be raised loads for reaction to occur quick enough
∴ would be expensive + less iron would be produced as the reaction is reversible
polyethene made with ziegler-natta catalyst:
-more dense+rigid+higher melting point
how does increased temperature affect rate of reaction (maxwell-boltzmann)?
more particles will have the least Ea ∴ be able to react (curve moves right)
how does increasing pressure affect rate of reaction?
more particles in given volume of gas ∴ more frequent successful collisions
how does increasing SA affect rate of reaction?
increases surface exposure at which collisions can happen
how do catalysts increase rate of reaction?
lower Ea by finding alternative pathway for bonds to be broken + re-made ∴ more particles will have enough energy to react
what is heterogeneous catalysis?
heterogeneous catalysts are in a different physical state to the reactants
-e.g. solid iron catalyst in haber process used for gas
where does the reaction occur in heterogeneous catalysis?
on the surface of the heterogeneous catalyst ∴ increasing SA of it increases amount of molecules that can react at the same time ∴ increasing rate of reaction
what is a homogeneous catalyst?
-same physical state as reactant
-catalyst + reactant combine to make intermediate species which reacts to form products + reformed catalyst
what is rate of reaction?
change in amount of reactants and products per unit of time
