J.I. Siepmann
Chem 8561
46
IDEAL POLYATOMIC GAS
• a polyatomic molecule consists of three or more nuclei and many electrons
• to derive the canonical partition function for polyatomic molecules, we will follow
a similar approach as used for the diatomic m
A+B=X+Y
0 = B B
B
The Nobel Prize in Chemistry 1901
Jacobus Henricus
van 't Hoff
Berlin University
Berlin, Germany
b.1852
d.1911
in recognition of the extraordinary services he has
rendered by the discovery of the laws of chemical
dynamics and osmotic pr
1. (2)
(4)
(5)
(6)
(7)
2. (1)
(2)
(3) Tpx
(4)
(5)
(6)
(7)
(8) pA = kA cA , pA = k B cB pA = pB kA > kB cA < cB
3. (1) ln xA =
*
vap H m 1 1
V
pA pA fus H m 1 1
=
( *) =
( * ) = A,m
*
pA
R
Tf Tf
R
Tb Tb
RT
(2) dG = SdT + Vdp
1.
(1) SdT Vdp + nB d B = 0
(2) mix S = R nB ln xB
B
(3) mix G = RT nB ln xB
B
(4) ln x A =
VA , m
RT
(5) V = nB RT
(6) B =
pB
*
p B xB
(7) B =
pB
k B cB
(8) (
ln p A
ln pB
)T = (
)T
ln x A
ln xB
2.
(1)
(2)
(3) B xBmBcB
(4) p T
(5)
(6)
(7) 2
1 p = pB
2
1 dU = Q pdV
2 H = U + pV
3 H = Q p ; U = QV
T2
T2
T1
T1
4 H = C p dT U CV dT
5 W = nRT ln
V2
V1
6 W = pV
7 pV =
8 W =
p1V1 p2V2
1
9 W =
nR
(T T )
1 1 2
3
1
2
3
4 U = QV H = Q p QV , QP
5
6
H = Q p = 0
7