Mattingley and Fenby [J. Chem. Thermodyn. 7, 307 (1975)] have reported that the enthalpies of triethylamine-benzene solutions at 298.15 K are given by

where x_B is the mole fraction of benzene and H_mix, H_B, and H_EA are the molar enthalpies of the mixture, pure benzene, and pure triethylamine, respectively, with units of J/mol.

a. Develop expressions for (H̅_B − H_B) and (H̅_EA − H_EA).

b. Compute values for (H̅_B −H_B) and (H̅_EA −H_EA) at x_B = 0.5.

c. One mole of a 25 mol % benzene mixture is to be mixed with one mole of a 75 mol % benzene mixture at 298.15 K. How much heat must be added or removed for the process to be isothermal?

Transcribed Image Text:

Hmix - [BHB + (1 - XB)HEA] = XB(1 - XB) {1418 - 482.4(1 - 2X³) +187.4(1 - 2xB)³}