Problem 1: The table below gives the enthalpy of benzene(1)-heptane(2) solutions at 20 °C 1 bar as a function of the mol fraction of benzene.
a) Calculate and plot the excess enthalpy at 20 °C, 1 bar.
b) Calculate the partial molar excess enthalpy at x1 = 0.2, 20 °C, 1 bar.
c) Calculate the heat that is released or absorbed when 10 mol of benzene is mixed with 40 mol of heptane isothermally at 20 °C, 1 bar.
d) Calculate the temperature change when 10 mol of benzene is mixed with 40 mol of heptane adiabatically, 1 bar., if the initial temperature of the pure components is 20 °C. The heat capacity of the pure liquids are CP 1 = 134 J/mol, CP 2 = 222 J/mol K.
| x1 |
H(J/mol) |
x1 |
H(J/mol) |
| 0 |
635 |
0.5 |
1229.51 |
| 0.14 |
956.91 |
0.58 |
1185.85 |
| 0.2 |
1035.06 |
0.65 |
1110.76 |
| 0.22 |
1066.37 |
0.71 |
1005.74 |
| 0.3 |
1174.31 |
0.83 |
688.42 |
| 0.33 |
1184.04 |
0.88 |
537.71 |
| 0.37 |
1203.61 |
1 |
-50 |
| 0.44 |
1237.33 |
|
|