Electrochemistry - Calculation of Ecell.

One of the uses in the calculation of E_cell is that it can used to predict the feasibility of a redox reaction. When E_cell^o >0, the redox reaction is feasible. The converse implies that the redox reaction is not feasible.

The following steps are used in the calculation:

(1) Predict which is the species that will be oxidised.

(2) Predict which is the species that will be reduced.

(3) Write the half-equation for the species that is oxidised; ensuring that it is found on the RHS.

(4) Write the half-equation for the species that is reduced; ensuring that it is found on the LHS.

(5) Apply anti-clockwise rule to calculate E_cell^o

The video below takes you through the above steps, demonstrate how the E_cell^o is calculated for a reaction between Zn and Cu²⁺ .



Lastly, when calculating the E_cell^o, please be mindful that we assume that the standard condition of 1 moldm^-3 was used. However, when a smaller (or different) concentration is used, the reduction potential of the species is affected because of Le Chatelier's Principle as the equilibrium is affected.

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Article written by Kwok YL 2009.}

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