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