Define standard cell potential, $E^\ominus_{\text{cell}}$. Include a description of standard conditions.
Draw a labelled diagram of this electrochemical cell. Include every necessary substance and the relevant pieces of apparatus needed to measure the $E^\ominus_{\text{cell}}$. It is not necessary to state the conditions used.
State the charge carriers that transfer current through the solutions and through the wire.
The standard electrode potential, $E^\ominus$, for the $\text{Zn}^{2+}(\text{aq})/\text{Zn}(\text{s})$ electrode is $-0.76\,\text{V}$. Water is then added to a standard $\text{Zn}^{2+}(\text{aq})/\text{Zn}(\text{s})$ electrode. The resulting concentration of $\text{Zn}^{2+}(\text{aq})$ is $0.25\,\text{mol dm}^{-3}$. Use the Nernst equation to calculate the electrode potential, $E$, for this new $\text{Zn}^{2+}(\text{aq})/\text{Zn}(\text{s})$ electrode.
An electrochemical cell is built from a $\text{ZnO}/\text{Zn}$ electrode and a $\text{MnO}_2/\text{Mn}_2\text{O}_3$ electrode in an alkaline electrolyte. The standard cell potential, $E^\ominus_{\text{cell}}$, for this cell is $+1.47\text{ V}$. The half-equation at each electrode during discharge is shown. $\text{Zn} + 2\text{OH}^- \rightarrow \text{ZnO} + \text{H}_2\text{O} + 2e^-$; $2\text{MnO}_2 + \text{H}_2\text{O} + 2e^- \rightarrow \text{Mn}_2\text{O}_3 + 2\text{OH}^-$. Use this information to determine the change in oxidation state of manganese when this cell is discharging.
Write the equation for the overall reaction that occurs when this cell is discharging.
The $E^\ominus$ for the $\text{ZnO}/\text{Zn}$ electrode is $-1.28\text{ V}$. Calculate the standard electrode potential, $E^\ominus$, for the $\text{MnO}_2/\text{Mn}_2\text{O}_3$ electrode.