1. Ideal solutions and excess functions
Part V

2. problem
The data in Table 11.2 are experimental values of VE for binary liquid mixtures of 1,3-dioxolane(1) and isooctane(2) at K and 1 atm.
(a) Determine from the data numerical values for a, b, and c in:

4. Numerical problem: find the values of a, b, and c that best fit
to the given set of data
a = 3448; b = -3202; c =

5. (b) Determine the maximum value of VE and the value of x1 at which this occurs.
dVE/dx1 = 0 and solve for x1
VEmax = cm3/mol ; x1 =0.353

6. c) From the results of part (a) find expressions for
Prepare a plot and discuss its features

7. Slopes 0 as x1->1
Maximum in one pmp agrees with minimum at the other, inflection point for VE
Where the VE has a maximum the pmps cross.

8. Temperature dependence of excess properties

10. example
If CPE is a constant, independent of T, find expressions for GE, SE, HE for an equimolar solution of benzene(1)/n-hexane(2) at K, given the following excess-property values for an equimolar solution at K
CPE = J/mol K; HE = J/mol;
GE = J/mol

11. From
Also,

12. using the values at K
We already know the value of a = (equal to CPE)
From HE obtain c =1,750.6
From GE obtain b =
Now calculate GE, SE, HE at K

13. problem
Given the following data for equimolar mixtures of organic liquids. Use all the data to estimate values of GE, HE, and TSE for the equimolar mixture at 25oC
At T = 10oC, GE =544 and HE =932.1
At T = 30oC, GE = 513.2, HE =893.4
At T = 50oC, GE = 494.2, HE = 845.9
Energies are in J/mol

14. Assume CpE is constant (a)
Then HE = aT + c
Use the three sets of HE data and get the best values of a and c; a= ; c = 1544
With a and c get b for each set of GE data; then take b average.
Finally calculate GE, HE, TSE at 25oC using the a, b, and
c parameters