Enter your Cathode and Anode Standard Potentials (E°), Temperature, Electrons Transferred (n), and Ion Concentrations to calculate the Cell EMF — along with Standard Cell EMF (E°cell), Nernst Correction, and Reaction Quotient (Q) showing how far your cell strays from standard conditions.
Cell EMF
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Standard Cell EMF (E°)
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Nernst Correction
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Reaction Quotient (Q)
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EMF (Electromotive Force) is the potential difference between two electrodes in an electrochemical cell. It represents the maximum voltage the cell can produce when no current is flowing and is measured in volts (V).
Cell EMF is calculated using E°cell = E°cathode - E°anode for standard conditions. For non-standard conditions, use the Nernst equation: Ecell = E°cell - (RT/nF)ln(Q), where Q is the reaction quotient.
The cathode has a higher reduction potential and is where reduction occurs (electrons are gained). The anode has a lower reduction potential and is where oxidation occurs (electrons are lost). The EMF is the difference between these potentials.
Temperature affects cell EMF through the Nernst equation. Higher temperatures generally decrease the EMF for most galvanic cells, while lower temperatures increase it. This is because the RT term in the Nernst equation is directly proportional to temperature.
Electrode potentials should be entered in volts (V). Standard reduction potentials are typically given relative to the standard hydrogen electrode (SHE), which has a potential of 0.00 V by definition.
Ion concentrations affect cell EMF through the reaction quotient (Q) in the Nernst equation. Higher concentrations of reactants increase EMF, while higher concentrations of products decrease EMF. At standard conditions (1 M), Q = 1 and the Nernst correction is zero.
A galvanic cell is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two electrodes (cathode and anode) connected by an electrolyte and external circuit.
Yes, if the calculated EMF is negative, it means the reaction is non-spontaneous under the given conditions and the cell cannot produce electrical energy. The reaction would need external energy input to proceed.