Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

(a(i))[2]

Define what is meant by standard cell potential.

(a(ii))[1]

Complete the table by giving the material used to make the electrode in each of these half-cells, for the $\text{Co}^{3+}/\text{Co}^{2+}$ half-cell and the $\text{Cl}_2/\text{Cl}^-$ half-cell.

(a(iii))[1]

Use values from the Data Booklet to calculate the standard cell potential, $E^\circ_{\text{cell}}$.

(a(iv))[1]

Write the equation for the overall reaction in the cell.

(b)[2]

A fuel cell is an electrochemical cell used to produce electrical energy. A methanol-oxygen fuel cell can act as an alternative to a hydrogen-oxygen fuel cell. During operation, the carbon atoms in the methanol molecules are converted into carbon dioxide. $\text{CH}_3\text{OH} + \text{H}_2\text{O} \rightarrow \text{CO}_2 + 6\text{H}^+ + 6e^-$ Calculate the volume of $\text{CO}_2$, in $\text{cm}^3$, produced when a current of $2.5\ \text{A}$ is delivered by the cell for $30$ minutes. Assume the cell operates at room conditions.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: potential difference across two half-cells/electrodes

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