Learning Goal: To understand the components and processes of a galvanic cell. A

Question

Learning Goal:

To understand the components and processes of a galvanic cell.

A galvanic cell (or voltaic cell) produces electricity using a spontaneous redox reaction, such as the one shown here:

Fe(s)+Cu2+(aq)Fe2+(aq)+Cu(s)

The components of this reaction are separated by a salt bridge and connected with a wire, forcing the electrons to travel across the wire, creating electricity.

The salt bridge is a U-shaped glass tube that is filled with a gel-like substance containing a salt. The salt bridge completes the circuit and allows ions to flow, maintaining electrical neutrality in the solutions.

What is the standard potential, Ecell, for this galvanic cell? Use the given standard reduction potentials in your calculation as appropriate.

Express your answer to three decimal places and include the appropriate units.

Explanation / Answer

What is the standard potential, Ecell, for this galvanic cell? Use the given standard reduction potentials in your calculation as appropriate.

Remember that each species will have a specific reduction potential. Remember that this is, as the name implies, a potential to reduce. We use it to compare it (numerical) with other species.

Note that the basis if 2H+ + 2e- -> H2(g) reduction. Therefore E° = 0 V

All other samples are based on this reference.

Find the Reduction Potential of each reaction (Tables)

Fe2+ + 2 e Fe(s) 0.44

Cu2+ + 2 e Cu(s) +0.337

The most positive has more potential to reduce, it will be reduced

The most negative will be oxidized, since it will donate it selectrons

The equation:

Fe(s)+Cu2+(aq)Fe2+(aq)+Cu(s)

For total E°cell potential:

E°cell = Ered – Eox

Eox = -Ered of the one being oxidized

E°cell =   0.337 - - 0.44= 0.777 V

E°cell = 0.777 V

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