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Flashcards in Kinetics Deck (33):
1

experimental methods

-pressure changes
- spectroscopic analysis
- flow method

2

beer-lambert

-log (I/I0) = EcL

3

Flow method

mix in chamber then forced through tube
different distances = different times elapsed
spectroscopy determines composition

4

Vr

1/stoichiometry d[A]/dt

5

determining rate law

-isolation
-initial rate
-integration
-half life
-time constant

6

Isolation method

pseudo 1st order

7

initial rates

isolated law =k'[A]^a
V0=k'[A0]^a
log both sides
logV0 against logA0
slope = a
intercept = logk'

8

integrated law

1st order -
A=A0exp(-kt)
can be done generally

9

Reaction half life

constant for 1st order
t1/2=ln(2)/k

10

reaction time constant

concentration to fall to 1/e
tau=1/k

11

second order curves

go to zero more slowly as rate depends on decreasing [A0] for each point

12

Arrhenius

k=Aexp(-Ea/RT)

13

Arrhenius parameters

A- number of collision
exp - ratio of molecules with sufficient energy

14

Steady state approximation

d[I]/dt = 0
solve for [I]
sub into d[p]/dt

15

Lindeman-hinshelwood

cyclopropane to propene
A+A to A + A* (reversible)
A* to P
First order at high pressure
second order at low

16

lindeman limitations

does not take into account necessary energy accumulation in one bond
A* to A^ to P

17

Lock and key

Shaped active site
Specific substrate

18

Induced fit

Alters shape to connect

19

Competitive inhibition

Competes for active site
Reduces ability to bind substrate

20

Non-competitive inhibition

Not influence binding
Alters activity

21

Allosteric inhibition

Induces conformational change
So substrate cannot bind

22

Michaelis- menten

E+S to ES Reversible
ES to P
Overall rate k[ES]
SSA sub E0 = E + S
Km= ka' + kb / ka
Vmax when s>> Km

23

PV =

1/3 n M csquared

24

C
Root mean square speed

Sqrt +


= sqrt( 3RT/M)

25

Fraction of molecule with speed v

F(v) =
4π(M/2πRT)^3/2 vsquared exp(-Mvsquared/2RT)

26

C bar
Average speed

Integral vf(v) 0 to infinity dv

C bar = sqrt(8RT/πM)

27

C* most probable speed

Sqrt (2RT/M)

28

Collision frequency

Z= sqrt 2 σ cbar N/V

σ = π dsquared

Time between collisions 1/z

29

Mean free path length

1/z cbar

30

Collision density

σ cbar [B] [A] Nasquared

C bar has μ instead of M
σ has d= (da+db)/2

31

Collision theory

DA/dt = Zab f /Na
F= exp (-Ea/RT)
Subsitution gives k
And therefore A from Arrhenius

32

Steric factor

Pxσ

33

Harpoon

P= P* squared/ d squared

E = IE-Eaff - coulombic

(esqaared/4 pi epsilon0 r)