Question

Physical Chemistry

Calculate the change in entropy when one mole of metallic aluminum is heated at one bar pressure from an initial temperature of 25 °C to a final temperature of 750 °C. The molar heat capacities of solid and liquid aluminum at one bar pressure are 29.2 J mol K1 and 31.75 J mol K, respectively. The specific enthalpy of fusion of aluminum at its melting point (660.46 °C) is 396.57 J g1. The molar mass of aluminum is 26.98 g mol. 2. (10 pts) a) Show that the molar entropy change, ASm, is given by 3. In2 ASm= Cv,m +RIn if one mole of an ideal gas is taken from T1 , Vi to T2 , V2 assuming that Cv m is independent of temperature. b) Calculate the value of the molar entropy change, ASm, if one mole of N2(g) is expanded from 20.0 dm at 273 K to 300 dm3 at 400 K. (Cp,m 29.4 J K-1mol-1) (10 pts)

Answer 1

hant we ASm Cv mlon T but Y liguid aanpe is nepigkle ndime ASra 1 660 46 250C Cin to elid tnte 660.4600 at m liguid te AC 48K 933- 660.460 660.4642725 n 933 6 29815 29 2 Jmed 33. 3 3 J/K

A- Imele 27 /mat 396 53 10구07.39 302. 39 J/mel 33-6 K 1147 1 k AS 933-61 L023.15 mot23. I5 = 2.9 AS ASt AS 4713K 1 that 3. lare dat dw du - da-pdv aC dT CdT tPdv ds Tds

Replace tds = CdT + Pdv Pdv R dv V P V ERT Cp-C R 29.41 Kmed &-314 1/Eog 21. 0&6 3/kmo 3 00 & .314 m 21.086 m 2a रतेउ 246.1 /K