An electrochemical system is prepared by immersing a copper electrode in of solution…

CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry

Problem

An electrochemical system is prepared by immersing a copper electrode in

25.0\,\text{mL}

0.0100\,\text{M}\,\text{Cu}^{2+}

solution and a silver electrode in

25.0\,\text{mL}

0.00100\,\text{M}\,\text{Ag}^{+}

solution at

298\,\text{K}

. The two half-cells are connected by a salt bridge and by an external wire through a high-resistance voltmeter. Standard reduction potentials are

\text{Ag}^{+} + e^- \rightarrow \text{Ag(s)} \quad E^{\circ} = +0.80\,\text{V}

\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu(s)} \quad E^{\circ} = +0.34\,\text{V}

A student then adds

1.00\,\text{mL}

0.500\,\text{M}\,\text{AgNO}_{3}(aq)

to the silver half-cell and

1.00\,\text{mL}

0.500\,\text{M}\,\text{Cu(NO}_{3})_{2}(aq)

to the copper half-cell, causing negligible total-volume change. (a) Calculate the cell potential immediately before any additions are made. (b) Determine the new ion concentrations in each half-cell after the additions have been made, assuming perfect mixing and negligible volume change. (c) Calculate the cell potential after the additions. Show all work including the computation of the reaction quotient. (d) Explain, with reference to

Q

and

K

, whether the additions in part (b) moved the system closer to or farther from equilibrium and how this is reflected in the change in potential.

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