Question 1

How do I calculate E°_cell?

Accepted Answer

E°_cell = E°_cathode - E°_anode. Use the standard reduction potentials for both half-cells. The cathode is where reduction occurs, and the anode is where oxidation occurs. A positive E°_cell means the reaction is spontaneous.

Question 2

What is the standard hydrogen electrode?

Accepted Answer

The SHE (Standard Hydrogen Electrode) is the reference electrode with E° = 0.000 V. All other standard reduction potentials are measured relative to the SHE. The half-reaction is 2H⁺ + 2e⁻ → H₂.

Question 3

What is the difference between galvanic and electrolytic cells?

Accepted Answer

A galvanic (voltaic) cell has a positive E°_cell and spontaneously generates electricity. An electrolytic cell has a negative E°_cell and requires external electricity to drive the non-spontaneous reaction.

Question 4

Do I flip the sign of E° for the anode?

Accepted Answer

No. Always use standard reduction potentials from the table as-is. The formula E°_cell = E°_cathode - E°_anode already accounts for the anode undergoing oxidation (the reverse of reduction).

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