Kinetics Flashcards
What factors increase the rate of a reaction?
1) Higher temperature
2) Catalyst added, lower activation energy
3) Physical state (better if all same state)
4) Higher concentration of reactants
5) Higher frequency factor, meaning better steric/orientation factor and higher collision frequency between molecules
6) Higher reactivity of reactants
How do we know what factors increase or decrease K (rate constant)?
Arrhenius equation, given in notes sheet of test
What factors increase K (rate constant?)
1) Temperature
2) Frequency factor (higher steric/orientation factor and higher collision frequency between molecules)
How can we estimate activation energy given a graph of kinetics data?
1) Slope = rate constant K
2) K = -Ea/R
3) Multiply K (slope value) by R and divide by -1 to get Ea by itself
Reaction intermediate
Produced in one step of a mechanism and then consumed in another. Cannot be in a suggested rate law.
Molecularity
How many molecules must come together. Add up moles on reactants side. 1 = unimolecular, 2=bimolecular, so on so forth
Rate-determining step
Always the slowest step of a mechanism
What tells us the concentration as a function of time?
Integrated rate laws
How can you tell the rate determining step from a graph?
Highest Ea
How do we know when a proposed mechanism is valid?
1) Balanced net reaction is correct
2) Consistent with experimental data
3) Composed of a series of elementary steps
4) Final rate law has NO intermediates
0th order units for K
M/s
1st order units for K
s-1
2nd order units for K
M-1s-1
ideal gas law
PV = nRT
if variables on one side of an equation go up, other side goes up. Variables on the same side go down.
ex. pressure goes up, volume goes down, moles go up, t goes up
ex. volume goes up, p is constant, t and n go up
