Chapter 45 Flashcards
What factors affect the rate of the rxn?
- Concentration
- Temperature
- Catalyst
deltaH<0
exo or endo?
exo
deltaH>0
exo or endo?
endo
activation energy
minimum energy needed to start a rxn (to get to act. complex)
Which reactions are reversible: endo or exo?
edno rxn are reversible; exo rxn are not reversible bc of the activation energy needed
catalyst
lowers act. energy; speeds up rxn; mainly added to endo rxns
reactant of one step, prod in another
reaction mechanism
step wise pathway that describes HOW reactants are converted into products; each step is elementary steps
unimolecular
A –> product
bimolecular
2A –> product or A + B –> prod
termolecular
A + A + B –> product
intermediate
product in one step, reactant in the next step
homogeneous catalysis
reactants and catalyst in the same phase
heterogeneous catalysis
reactants and catalysts in different phase
rates at equilibrium
opp rates are equal
act. complex
whats formed from collision of reactant molecules; the microsecond in time A&B collided successfully
first order rxn
A –> product
rate = k[A]
slope = -k
half life for first order rxn
ln 2/k
second order rxn
A –> product
rate = k[A]^2
zero order rxn
A –> product
rate = k
What is the rate determining step (RDS)?
slowest step, overall rate depends on this step, sets pace for whole rxn
the longer the time……
….the more stable the reactant
reactions occur by themselves bc…..
they want to become more stable
what helps make collisions more effective?
heat
Graph of Ea: what is the top of the hump?
transition state
the higher the act. energy
reactants less stability
the more stable the reactants….
…..the less stable the product
