(a) From the data in Appendix 2A, calculate the enthalpy of vaporization of benzene (C₆H₆) at 298.2 K. The standard enthalpy of formation of gaseous benzene is 182.93 kJ · mol^–1. 

(b) Given that, for liquid benzene, C_P,m = 136.1 J · K^–1 · mol^–1 and that, for gaseous benzene, C_P,m = 81.67 J ·K^–1 · mol^–1, calculate the enthalpy of vaporization of benzene at its boiling point (353.2 K).

(c) Compare the value obtained in part (b) with that found in Table 4C.1. What is the source of the difference between these numbers?

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2A THERMODYNAMIC DATA AT 25 °C Inorganic Substances Substance Aluminum Al(s) Al³+ (aq) AI(OH)3(s) Al₂O3(s) AlCl3(s) AlBr,(s) Antimony Sb(s) SbH3(g) SbCl3(g) SbCls (g) Arsenic As(s), gray AsO³(aq) A$2S3(S) Barium Ba(s) Ba²+ (aq) BaO(s) BaCO3(s) BaCO3(aq) Molar mass, M/(g.mol-¹) 26.98 26.98 78.00 101.96 133.33 266.68 121.76 124.78 228.11 299.01 74.92 138.92 246.05 137.33 137.33 153.33 197.34 197.34 Enthalpy of formation, AH/(kJ-mol-¹) 0 -524.7 -1276 -1675.7 -704.2 -527.2 0 +145.11 -313.8 -394.34 0 -888.14 - 169.0 0 -537.64 -553.5 -1216.3 -1214.78 Gibbs free energy of formation, AG/(kJ.mol-¹) 0 -481.2 -1582.35 -628.8 0 +147.75 -301.2 -334.29 0 -648.41 -168.6 0 -560.77 -525.1 -1137.6 -1088.59 Molar heat capacity, Cr.m/(J.K¹-mol¹) 24.35 79.04 91.84 100.6 25.23 41.05 76.69 121.13 24.64 116.3 28.07 47.78 85.35 Molar entropy, Sm/(J-K¹-mol-¹) 28.33 -321.7 50.92 110.67 180.2 45.69 232.78 337.80 401.94 35.1 -162.8 163.6 62.8 +9.6 70.42 112.1 -47.3