Cell Potential Under Nonstandard Conditions
When concentrations differ from standard, the cell potential is given by the Nernst equation: at 25 °C, E = E° − (0.05916/n) log Q. So the potential shifts away from E° as Q changes — an operating cell is not pinned to its standard value, a concentration cell (same species, different concentrations) has a nonzero potential, and E reaches zero only at equilibrium.
The trap keeps the cell potential at its standard value as conditions change, moves it the wrong direction, calls a concentration cell zero-voltage, or treats a working cell as already at equilibrium. Use the Nernst equation: E shifts from E° with Q, and only hits zero at equilibrium.
The work
3 ways in · any order
Lesson
Nonstandard Cell Potential
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The Nernst equation shifts E from E° with Q, so an operating (and concentration) cell has a nonzero, nonstandard potential until equilibrium. The lesson applies it, then closes with a ten-scenario check.
Diagnostic
10-item topic check
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Ten items spanning the Topic 9.10 misconception: nonstandard and operating cell potential mishandled — the Nernst shift, concentration cells, and the zero-at-equilibrium condition.
Targeted Practice
Drill a single misconception
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Pick one of the failure modes you missed and drill it on its own. The round is adaptive: two correct in a row clears the misconception and moves you to the next.