文档介绍:Chapter 9
Solutions
Ideal Solutions
Solutions
A solution where the molecules of the various species are so similar to one another that replacing molecules of one species with molecules of another species will not change the spatial structure or the intermolecular interaction energy in the solution.
B at T, P
C at T, P
B + C at T, P
B-B, C-C
B-B, C-C,
B-C
To prevent change on mixing B and C, the size and shape of B molecules those of C
The intermolecular interaction energies should be essentially the same for B-B, B-C, and C-C pairs of molecules.
Physical Chemistry
Ideal Solutions
Solutions
When two liquids B and C whose molecules resemble each other closely are mixed at constant T and P, the experimental mixG is
From the molecular definition, the formation of an ideal solution from ponents at constant T and P
()
Physical Chemistry
B at T, P
C at T, P
B + C at T, P
Ideal Solutions
Solutions
()
For ideal gases
For ideal solutions
()
Physical Chemistry
Ideal Solutions
Solutions
For ideal solutions
For ideal solutions (ideal liquid or solid mixtures) containing the gas constant R?
()
R applies not only to the zero-pressure limit of a gas
But also to entropy
And other fundamental equations of statistical mechanics!
()
Avogadro constant
Boltzmann’s constant
Physical Chemistry
Ideal Solutions
Solutions
For ideal solutions
()
Thermodynamic definition of an ideal solution:
()
()
ideal solution
()
Physical Chemistry
Ideal Solutions
Solutions
Thermodynamic definition of an ideal solution:
A solution is ideal if the chemical potential of ponent in the solution obeys () for all positions and for a range of T and P.
ideal solution
()
Molecular definition of an ideal solution:
A solution where the molecules of the various species are so similar to one another that replacing molecules of one species with molecules of another species will not change the spatial structure or the i