Electron Transfer Flashcards

1
Q

As the reduction potential for a molecule become more negative, it becomes a stronger __________.

Reducing agent or Oxidizing Agent

A

Reducing agent

(The oxidized form is thermodynamically more stable)

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2
Q

Two of the same element in different oxidation states combine to the same oxidation.

A

Comproportionates

Pb(s) + PbIVO2 + 2H2SO4 —–> PbIISO4 + 2H2O

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3
Q

What oxidation state of Manganese is more stable under strongly basic conditions?

A

Oxidation state +3

Mn2O3

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4
Q

If Ecell < 0, than the electron transfer reaction is __________.

Endergonic or Exergonic ​

A

Endergonic (non-spontaneous)

(Remember: ΔGo = -nFEocell)

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5
Q

If Ecell > 0, than the electron transfer reaction is __________.

Endergonic or Exergonic ​

A

Exergonic (spontaneous)

(Remember: ΔGo = -nFEocell)

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6
Q

Electron transfer that occurs with no direct bond between redox partners.

A

Outer Sphere Electron Transfer

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7
Q

Electron transfer that occurs with the formation of bonds between redox partners and the bridging group often (though not always) transfers

A

Inner Sphere Electron Transfer

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8
Q

Mixed valence compounds where the valence is completely delocalized.

A

Class III - Valence Delocalized

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9
Q

Mixed valence compounds where there is some localization of distinct valences, but there is a low activation energy for their interconversion.

A

Class II - Intermediate

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10
Q

Compounds where the valences are trapped—localized on a single site.

A

Class 1-Valence Localized​

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11
Q

What type of equilibrium exist between species across diagonal boundary lines in a Pourbaix diagram?

A

Proton Dependent Redox Reactions

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12
Q

What type of equilibrium exist between species across horizontal boundary lines in a Pourbaix diagram?

A

Proton Independent Redox Reactions

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13
Q

What type of equilibrium exist between species across vertical boundary lines in a Pourbaix diagram?

A

Acid-Base Equilibriums

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14
Q

According to Marcus Theory, an increase in driving force leads to an increase in electron transfer rate in this region?

A

The Normal Region

(Classical Region)

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15
Q

The biomolecular rate constants for outer-sphere self exhange mechanism tend to be ________ if they involve electron transfer to and from low lying antibonding orbitals.

Fast or Slow

A

Slow

Large changes in bond lengths are expected and therefore inter-sphere reorganization energy will be large

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16
Q

The parabolic potentials curve represent the_________.

A

Potential energy for vibrational states as a funtions of nuclear coordinates.

17
Q

The parameter β in Dutton’s Ruler represents the _______ in which the electron propagates.

A

Medium

18
Q

The proton and electron always propagate in the same directions in proton coupled electron transfer reactions.

True or False

A

False

19
Q

A chemical reaction that involves the transfer of both an electron and a proton at roughly the same time.

A

Proton Coupled Electron Transfer (PCET)

Note: This process lowers the free energy of successive electron transfers by creating a nearly charge neutral process.

20
Q

What is the voltage shift between each successive reduction with proton coupled electron transfer?

A

~400-600 mV shift per charge unit

21
Q

According to Marcus Theory, an increase in driving force leads to a decrease in electron transfer rates in this region?

A

The Inverted Region

(Note: Driving force is equal to the reorganization energy (λ) in this region)

22
Q

According to Marcus Theory, this region is where driving force is equal to the reorganization energy in this region?

A

The Activtionless Region

23
Q

The reorganization energy that can be assoicated with the rearrangement of the solvent surrounding the electron transfer centers.

A

Outer-Sphere Reorganization Energy

24
Q

The reorganization energy that can be assoicated with the instrictic geometry change that occurs on a redox center.

A

Inner Sphere Reorganization Energy

25
Q

As the distance between an electron donor and an acceptor increases, the rate of electron transfer______.

Increases or Decreases

A

Decreases

26
Q

For a one electron transfer reation that is reversible, what is the seperation between the oxidation peak potenital (Epa) and reduction peak potenital (Epc)?

A

59mV

27
Q

In the Pourbaix diagram for Mn, which boundary line represents the following equilibrium:

Mn ⇌ Mn(II) + 2e-

A

This boundary line is horizontal and therefore electrons are transfered in the equilibrium with no proton depencence.

28
Q

Mn+2 under acidic conditions is stable to _________.

Conproportionation or Disproportionation

A

Conproportionation

If the species of interest lies below the line connecting it’s two adjacent species on a Frost Diagram, the two adjacent species are unstable with respect to conproportionation.

29
Q

Mn+3 under acidic conditions is unstable to _________.

Conproportionation or Disproportionation

A

Disproportionation

If the species of interest lies above the line connecting the two adjacent species on a Frost Diagram, that species is unstable with respect to disproportionation

30
Q

One compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states

A

Disproportionate

Hg2Cl2 → Hg + HgCl2

31
Q

E=Eo-(RT/nF)*ln([Red]/[Ox])

A

Nernst Equation

Eo- the standard cell potential

E-cell potential

F- Faraday constant

n- number of electrons

32
Q

Idenifity the following feature of a cyclic voltammogram​

A

Epc

The anodic peak potential

33
Q

Idenifity the following feature of a cyclic voltammogram​

A

Epc

The Cathodic peak potential

34
Q

Idenifity the following feature of a cyclic voltammogram​

A

E1/2 ( in V)

Estimate of the formal redox potential under a specfic set of conditions

35
Q

Idenifity the following feature of a cyclic voltammogram​

A

Reduction Event

36
Q

Idenifity the following feature of a cyclic voltammogram​

A

Oxidation Event

37
Q

As the reduction potential for a molecule become more positive, it becomes a stronger __________.

Reducing agent or Oxidizing Agent

A

Oxidizing agent

(The reduced form is ​thermodynamically more stable)