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24. Electrochemistry

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  1. 24.1 Electrolysis

    1. 24.1.1The identities of substances liberated during

      • Predict the identities of substances liberated during electrolysis from the state of electrolyte (molten or aqueous), position in the redox series (electrode potential) and concentration

    2. 24.1.2The relationship F = Le between the Faraday

      • State/apply: the relationship F = Le between the Faraday constant, F, the Avogadro constant, L, and the charge on the electron, e

    3. 24.1.3Calculate

      • Calculate:: (a) the quantity of charge passed during electrolysis, using Q = I t; (b) the mass and/or volume of substance liberated during electrolysis

    4. 24.1.4Determination of a value of the Avogadro

      • Describe the determination of a value of the Avogadro constant by an electrolytic method ⦵ ⦵

  2. 24.2 Standard electrode potentials E ⦵ , standard cell potentials E ⦵ cell and the Nernst

    1. • Define:: (a) standard electrode (reduction) potential; (b) standard cell potential

    2. • Describe the standard hydrogen electrode

    3. • Describe methods used to measure the standard electrode potentials of:: (a) metals or non-metals in contact with their ions in aq. solution; (b) ions of the same element in different oxidation states

    4. • Calculate a standard cell potential by combining two standard electrode potentials

    5. • Use standard cell potentials to:: (a) deduce the polarity of each electrode and hence explain/deduce the direction of electron flow in the external circuit of a simple cell; (b) predict the feasibility of a reaction

    6. • Deduce from E ⦵ values the relative reactivity of elements, compounds and ions as oxidising agents or as reducing agents

    7. • Construct redox equations using the relevant half-equations

    8. • Predict qualitatively how the value of an electrode potential, E, varies with the concentrations of the aq. ions

    9. • Use the Nernst equation, E = E° + (0.059/z) log([oxidised]/[reduced]), to predict concentration effects on electrode potential; e.g. Cu2+/Cu and Fe3+/Fe2+.

    10. • Use ΔG° = -nE°cellF.