Kinetics Flashcards
Energy barrier to reaction pathway
Activation energy
Transition state
Local energy maxima, unstable
Intermediate
Local energy minima, stable and can be isolated
Rate
-d[reactant]/dt or d[product]/dt
Rate at time t
Found with tangent of either graph of [product] against t or -[reactant] against t
General rate of
aA + bB → cC + dD
-1/ad[A]/dt
-1/bd[B]/dt
1/cd[C]/dt
1/dd[D]/dt
Differential rate equation
k[A]^m[B]^n
Pseudo-rate equation
When B is in large excess compared to A, [B] is roughly constant
Rate=k’[A]^m, where k’=k[B]^n
Method of initial rates
Initial rate=k’[A]0^m
Taking logs gives linear equation
Zeroth order integrated rate law
[A]=[A]0-kt
First order integrated rate law
[A]=[A0]e^(-kt)
ln[A]=ln[A]0
Second order (rate=k[A]^2) integrated rate law
1/[A]=1/([A]0)+kt
Second order (rate=k[A][B]) integrated rate law
ln(([B]/[B]0)/([A]/[A]0))
First order half life
ln(2)/k
Second order half life
1/([A]0k)
