free energy and nernst
Download
Skip this Video
Download Presentation
Free Energy and Nernst

Loading in 2 Seconds...

play fullscreen
1 / 9

Free Energy and Nernst - PowerPoint PPT Presentation


  • 104 Views
  • Uploaded on

Free Energy and Nernst. Oxidizing and Reducing Agents. The strongest oxidizers have the most positive reduction potentials. The strongest reducers have the most negative reduction potentials. Oxidizing and Reducing Agents.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Free Energy and Nernst' - ugo


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
oxidizing and reducing agents
Oxidizing and Reducing Agents
  • The strongest oxidizers have the most positive reduction potentials.
  • The strongest reducers have the most negative reduction potentials.
oxidizing and reducing agents1
Oxidizing and Reducing Agents

The greater the difference between the two, the greater the voltage of the cell.

free energy
Free Energy

G for a redox reaction can be found by using the equation

G = −nFE

where n is the number of moles of electrons transferred, and F is a constant, the Faraday.

1 F = 96,485 C/mol = 96,485 J/V-mol

free energy1
Free Energy

Under standard conditions,

G = −nFE

nernst equation
Nernst Equation
  • Remember that

G = G + RT ln Q

  • This means

−nFE = −nFE + RT ln Q

nernst equation1

RT

nF

ln Q

E = E −

2.303 RT

nF

log Q

E = E −

Nernst Equation

Dividing both sides by −nF, we get the Nernst equation:

or, using base-10 logarithms,

nernst equation2

2.303 RT

F

= 0.0592 V

0.0592

n

log Q

E = E −

Nernst Equation

At room temperature (298 K),

Thus the equation becomes

concentration cells

Ecell

  • For such a cell,

would be 0, but Q would not.

Concentration Cells
  • Notice that the Nernst equation implies that a cell could be created that has the same substance at both electrodes.
  • Therefore, as long as the concentrations are different, E will not be 0.
ad