Chemistry Reference
In-Depth Information
-0.5
-2.5
ρ = 0.4
ρ = 0.4
-1.0
-3.0
ρ = 0.2
ρ = 0.2
-1.5
-3.5
ρ = 0.001
ρ = 0.001
-2.0
-4.0
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
x
A
x
A
-1.5
ρ = 0.4
-2.0
ρ = 0.2
-2.5
ρ = 0.001
-3.0
0.0
0.2
0.4
0.6
0.8
1.0
x
A
FIGURE 2.5
Values of the KBIs for the same system as in Figure 2.3 at different
total
densities.
Finally, Figures 2.6 and 2.7 show the solvation Gibbs energies of A and B at vari-
ous temperatures and at various pressures. For the HR mixtures the solvation Gibbs
energies are
(
)
*
∆
Gp
=
σ
+
kT
ln
1
+
β
p
σ
A
AA
B
)
(2.76)
(
*
∆
Gp
=
σ
+
kT
ln
1
+
β
p
σ
B
BB
B
Here, the Δ
G
*
are in dimensionless units. In subsequent calculations we chose
ε
AA
= −1, and expressed Δ
G
*
in units of ε
AA
.
In the system of HR, the solvation Gibbs energy is related to the work of creating
a cavity produced by the HR particles, which are
solvated
in the mixture (Ben-Naim
1977; Rowlinson and Swinton 1982). The larger the temperature, or the pressure, the
greater the work required to create such a cavity.
