Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

(a)[2]

Define standard electrode potential, $E^{\ominus}$, and describe the standard conditions used.

(b(i))[3]

An electrochemical cell is assembled to determine $E^{\ominus}$ for the $\text{Ag}^+(\text{aq})/\text{Ag}(\text{s})$ electrode. Draw a labelled diagram of this electrochemical cell, including every necessary substance. You do not need to state the conditions used.

(b(ii))[1]

A separate electrochemical cell uses a lower concentration of $\text{Ag}^+(\text{aq})$ than that used in (b)(i). Suggest how the electrode potential, $E$, for the $\text{Ag}^+(\text{aq})/\text{Ag}(\text{s})$ electrode would differ from its $E^{\ominus}$ value. Explain your answer.

(c)[1]

Define enthalpy change of solution, $\Delta H^{\ominus}_{\text{sol}}$.

(d(i))[2]

Table 4.1 gives some relevant energy changes for $\text{AgNO}_3$. Complete the energy cycle in Fig. 4.1 so that it shows how the lattice energy, $\Delta H^{\ominus}_{\text{latt}}$, of $\text{AgNO}_3(\text{s})$ is related to the energy changes listed in Table 4.1. Include state symbols for all species.

(d(ii))[1]

Calculate the lattice energy, $\Delta H^{\ominus}_{\text{latt}}$, of $\text{AgNO}_3(\text{s})$. $\Delta H^{\ominus}_{\text{latt}} = \ldots\, \text{kJ mol}^{-1}$

(e)[3]

Suggest the order of the lattice-energy magnitudes for the metal nitrates NaNO$_3$(s), Mg(NO$_3$)$_2$(s) and RbNO$_3$(s). Explain your answer.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: Potential difference of a half-cell relative to SHE

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI