Download presentation

Published byDominick Pugmire Modified over 2 years ago

1
+ current, cathodic ic + potential, V - potential, V - current, anodic ia

2
+ current, cathodic ic Reduction + potential, V - potential, V Oxidation - current, anodic ia

3
**+ current, cathodic ic When no electroactive species is present,**

no current flows, no ic nor ia This is what background electrolyte should look like. + V - V +1.0 V -1.0 V - current, anodic ia

4
**Initially no current flows**

+ current, cathodic ic Starting at a + V, Initially no current flows + V - V +1.0 V -1.0 V - current, anodic ia

5
**is present ic will increase + current, cathodic ic**

If a reducible species is present ic will increase + current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

6
**And continue to increase + current, cathodic ic**

+ V - V +1.0 V -1.0 V - current, anodic ia

7
**Until all of the species is reduced. ic has reached a maximum. **

+ current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

8
**Then ic decreases until… + current, cathodic ic**

+ V - V +1.0 V -1.0 V - current, anodic ia

9
**background current level. + current, cathodic ic**

It again reaches the background current level. + current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

10
**Now the potential is reversed + current, cathodic ic**

- current, anodic ia

11
**And as V is more positive, The reduced species can be Re-oxidixed **

+ current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

12
**So ia decreases to a maximum + current, cathodic ic**

+ V - V +1.0 V -1.0 V - current, anodic ia

13
**Where all has been oxidized, + current, cathodic ic**

+ V - V +1.0 V -1.0 V - current, anodic ia

14
**Then ia decreases, back to the background level. + current, cathodic **

- current, anodic ia

15
**Important features: + current, cathodic ic +1.0 V -1.0 V**

Ec + V - V +1.0 V -1.0 V - current, anodic ia Ea

16
**+ current, cathodic ic E1/2 is ~ EoRed +1.0 V -1.0 V - current, anodic**

Ec E1/2 is ~ EoRed E1/2 + V - V +1.0 V -1.0 V - current, anodic ia Ea

17
**+ current, cathodic ic Using an Fe(3+) heme, Fe is electroactive,**

(and also the heme!) … All Fe(3+) + V - V +1.0 V -1.0 V - current, anodic ia

18
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

A little Fe(2+) formed + V - V +1.0 V -1.0 V - current, anodic ia

19
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

more Fe(2+) formed + V - V +1.0 V -1.0 V - current, anodic ia

20
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

Largest cathodic current, Max rate of Fe(2+) formed + V - V +1.0 V -1.0 V - current, anodic ia

21
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

Little Fe(3+) left; Less Fe(2+) forms; Decrease in ic + V - V +1.0 V -1.0 V - current, anodic ia

22
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

all Fe(2+) now + V - V +1.0 V -1.0 V - current, anodic ia

23
+ current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

24
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

A little Fe(2+) is re-oxidized to Fe(3+) +1.0 V -1.0 V - current, anodic ia

25
+ current, cathodic ic + V - V +1.0 V -1.0 V - current, anodic ia

26
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

Nearly all Fe(2+) has been oxized - current, anodic ia

27
**+ current, cathodic ic +1.0 V -1.0 V - current, anodic ia**

All back to Fe(3+). Cycle could be run again, many times. - current, anodic ia

28
**Important features: + current, cathodic ic +1.0 V -1.0 V**

Ec + V - V +1.0 V -1.0 V - current, anodic ia Ea

29
**E1/2 for Fe(3+/2+) reduction**

+ current, cathodic ic Ec E1/2 for Fe(3+/2+) reduction E1/2 + V - V +1.0 V -1.0 V - current, anodic ia Ea

30
**the black box Working Electrode:**

Where the redox reaction action occurs

31
**the black box Working Electrode:**

Where the redox reaction action occurs Reference Electrode: Defines “0” potential for the cell. We use Ag/AgCl

32
**the black box Working Electrode:**

Where the redox reaction action occurs Auxilliary Electrode: Needed to complete circuit. We use a Pt wire Reference Electrode:

33
**At start of CV experiment…**

the black box Working Electrode: Where the redox reaction action occurs Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) At start of CV experiment…

34
**Moving up the cathodic current peak…**

black box Working Electrode: Where the redox reaction action occurs Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Moving up the cathodic current peak…

35
**Still moving up the cathodic current peak…**

black box Working Electrode: Where the redox reaction action occurs Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Still moving up the cathodic current peak…

36
**After the maximum cathodic current peak…**

black box Working Electrode: Where the redox reaction action occurs Fe(2+) Fe(2+) Fe(3+) Fe(3+) Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) After the maximum cathodic current peak…

37
**Moving down the anodic current peak…**

black box Working Electrode: Where the redox reaction action occurs Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Moving down the anodic current peak…

38
**Sill moving down the anodic current peak…**

black box Working Electrode: Where the redox reaction action occurs Fe(2+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Sill moving down the anodic current peak…

39
**At end of CV experiment…**

the black box Working Electrode: Where the redox reaction action occurs Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) Fe(3+) At end of CV experiment…

40
In your CV scans of Fe(porphyrin)Cl, you will see: + ic - V + V Interpretation???? - ia

41
**How is the range of Heme Potentials**

in Respiration adjusted?

42
The Question asked: Can changing Heme substituents vary Fe(3+/2+) redcution potentials?

Similar presentations

OK

The Nernst Equation Standard potentials assume a concentration of 1 M. The Nernst equation allows us to calculate potential when the two cells are not.

The Nernst Equation Standard potentials assume a concentration of 1 M. The Nernst equation allows us to calculate potential when the two cells are not.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

What does appt only means of transportation Ppt on mohandas karamchand gandhi Ppt on quality education Ppt on travels and tourism Ppt on object-oriented programming encapsulation Price levels and the exchange rate in the long run ppt on tv Ppt on arabinose operon Mp ppt online registration 2014 Ppt on agriculture download Download ppt on endangered species tiger