(a) Define standard cell potential, Ecell. Include a description of standard conditions. [2] (b) The Daniell cell is an electrochemical cell consisting of a Cu2+(aq)/Cu(s) electrode and a Zn2+(aq)/Zn(s) electrode. (i) Draw a labelled diagram of this electrochemical cell. Include all necessary substances and relevant pieces of apparatus needed to measure the Ecell. It is not necessary to state the conditions used. [3] (ii) State the charge carriers that transfer current through the solutions and through the wire. the solutions the wire [1] (iii) The standard electrode potential, E°, for the Zn2+(aq)/Zn(s) electrode is –0.76 V. Water is added to a standard Zn2+(aq)/Zn(s) electrode. The new concentration of Zn2+(aq) is 0.25 moldm⁻³. Use the Nernst equation to calculate the electrode potential, E, for this new Zn2+(aq)/Zn(s) electrode. E (Zn2+(aq)/Zn(s)) = V [2] (c) An electrochemical cell consists of a ZnO/Zn electrode and a MnO2/Mn2O3 electrode in an alkaline electrolyte. The standard cell potential, Ecell, for this cell is +1.47V. The half-equation at each electrode when this cell is discharging is shown. Zn + 2OH¯ → ZnO + H2O + 2e¯ 2MnO2 + H2O + 2e¯ → Mn2O3 + 2OH¯ (i) Use this information to determine the change in oxidation state of manganese when this cell is discharging. from to [1] (ii) Write the equation for the overall reaction that occurs when this cell is discharging. [1] (iii) The E° for the ZnO/Zn electrode is –1.28V. Calculate the standard electrode potential, E°, for the MnO2/Mn2O3 electrode. E° (MnO2/Mn2O3) = V [1]