Consider the cell, Zn(s)|ZnCl2(0.0050 mol kg¯¹)|Hg₁₂Cl₂(s)|Hg(l), for which the cell reaction is HgCl2(s) + Zn(s) → 2 Hg(l) + 2 Cl¯(aq) + Zn²+(aq). The cell potential is +1.2272 V, E(Zn2+, Zn) = −0.7628 V, and E(Hg₂Cl₂,Hg) = +0.2676 V. (a) Write the Nernst equation for the cell. Determine (b) the standard cell potential, (c) AG, AG, and K for the cell reaction, (d) the mean ionic activity and activity coefficient of ZnCl2 from the measured cell potential, and (e) the mean ionic activity coefficient of ZnCl2 from the Debye-Hückel limiting law. (f) Given that (♂E cell/ƏT) p = −4.52 × 10¯ª V K¯¹, Calculate AS and AH.

Consider the cell, Zn(s)|ZnCl2(0.0050 mol kg¯¹)|Hg₁₂Cl₂(s)|Hg(l), for which the cell reaction is HgCl2(s) + Zn(s) → 2 Hg(l) + 2 Cl¯(aq) + Zn²+(aq). The cell potential is +1.2272 V, E(Zn2+, Zn) = −0.7628 V, and E(Hg₂Cl₂,Hg) = +0.2676 V. (a) Write the Nernst equation for the cell. Determine (b) the standard cell potential, (c) AG, AG, and K for the cell reaction, (d) the mean ionic activity and activity coefficient of ZnCl2 from the measured cell potential, and (e) the mean ionic activity coefficient of ZnCl2 from the Debye-Hückel limiting law. (f) Given that (♂E cell/ƏT) p = −4.52 × 10¯ª V K¯¹, Calculate AS and AH.

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter16: Thermodynamics: Directionality Of Chemical Reactions

Section: Chapter Questions

Problem 91QRT: Actually, the carbon in CO2(g) is thermodynamically unstable with respect to the carbon in calcium...

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Actually, the carbon in CO2(g) is thermodynamically unstable with respect to the carbon in calcium carbonate(limestone). Verify this by determining the standardGibbs free energy change for the reaction of lime,CaO(s), with CO2(g) to make CaCO3(s).
Table 17-1 lists common half-reactions along with the standard reduction potential associated with each half-reaction. These standard reduction potentials are all relative to some standard. What is the standard (zero point)? lf is positive for a half-reaction, what does it mean? If is negative for a half-reaction, what does it mean? Which species in Table 17-1 is most easily reduced? Least easily reduced? The reverse of the half-reactions in Table 17-1 are the oxidation half-reactions. How are standard oxidation potentials determined? In Table 17-1, which species is the best reducing agent? The worst reducing agent? To determine the standard cell potential for a redox reaction, the standard reduction potential is added to the standard oxidation potential. What must be true about this sum if the cell is to be spontaneous (produce a galvanic cell)? Standard reduction and oxidation potentials are intensive. What does this mean? Summarize how line notation is used to describe galvanic cells.
Consider the cell, Zn(s)|ZnCl2(0.0050 mol kg−1)|Hg2Cl2(s)|Hg(l), for which the cell reaction is Hg2Cl2(s) + Zn(s) → 2 Hg(l) + 2 Cl−(aq) + Zn2+(aq). The cell potential is +1.2272 V, E⦵(Zn2+,Zn) = −0.7628 V, and E⦵(Hg2Cl2,Hg) = +0.2676 V. (a) Write the Nernst equation for the cell. Determine (b) the standard cell potential, (c) ΔrG, ΔrG⦵, and K for the cell reaction, (d) the mean ionic activity and activity coefficient of ZnCl2 from the measured cell potential, and (e) the mean ionic activity coefficient of ZnCl2 from the Debye–Hückel limiting law. (f) Given that (∂Ecell/∂T)p = −4.52 × 10−4 V K−1, Calculate ΔrS and ΔrH.
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