Question

Effect of Temperature on Cell Potential Cell designation: E (measured) Temperature (°C) PbPb2+ || Cu2+ Cu; 0.455 Temperature (K) AG (calculated) 0.497 295 0.512 Sn Sn2+ || Cult | Cu; 0.548 0.554 279 295 0.566 343 Y AS determined from the slope of a plot of AG versus T AS Pb Cur AS Sn|Cu = AH° Pb | Cu=- AHSn Cu=- AHº calculated at 298 K (show calculations) from AG = AH-TAS AH = AG+TAS

Answer 1

1) Effect of Temperature on cell potential: - In first case. The ull is Rubellest pb/pb+2 || cuthieu Pb(2e & pbt2(aq) anode reaction. Cath(aq) the culs) cathode reaction. 22 22 70 Pbls)+cu +2 (aq) = P3+2 (aq) + luls). The change in Gibbs free energy th=-1. F. E cull In this case n=2. F= 96,500 C., For this cell the table is :- Eau (measured) Temperature (°c) Temperatur (K) Aho-nf Eun (calculated) Volt KI 1) 0.455 279 - 87.81 2) 0.497 295 -95.92 3) 0.512 343 - 98.81 = In second case, the cell is Salsnt2 || cut2/ca. the cell real tim is :- Sn(s) -2e - Int2(aq) → Anode reaction. Euth(aq) +20 F (u (3) lathode reaction Sn(s) teuth (aq) ↑ Sa+2(aq) + Culs). In this case n=2, And the table is ! - Eau (measured) Temperature (°C) Temperature (°F) AG= nF Full (Calculated that Volt 1) 0.548 - 105.76 2) 0.554 I 22 295 - 106.92 3) 0.566 I 70 343 - 109.23 We know that the AH-T.AS. We plot the Ah Vs T in eau for both cell tum the curve slope: - As so-slope and Alta intercept 279

Cell-1 y = -0.146x - 49.52 -86 - 200 220 240 260 280 300 320 340 360 delta G -100 -102 temperature(degree F)

Forcell - we get a straight time plot (least fitting) ocurre in Ahrs Temperture. The equation of this least squre fithing on line Y = -0.1462-49.52 slope = -0.146 and AH = intercept w - AS =-0.146 WOH = - 49.52 kJ. " As = 0.146 kJ so this cell reaction is thermaly and entropically favourable. & AS pb|cu = 0.146 kJ ck" and Ah palm = -49,52 kJ. =1469.kl

Cell-2 y = -0.052x - 91.16 -105.5 100 200 TTT 30040 400 -106 -106.5 delta G -107 -107.5 -108 -108.5 -109 -109.5 temperature(degree F)

On the other hand, for cell-2, vento we also get a straight line (heast squre fitting) cury and the equation of this line is y=-0.052a-91.16 AS :- Slope = 0.052 and AH = intercept = -91.1 As sollu = 0.052kJ okt ad AH = -91. 16 kJ -52 J. so this cell reaction is also thermally ad entropi