Морозов В.Г., Фетисов Ю.К. Молекулярная физика. Курс физики. Часть 1
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bcd
bcd
V
p
0
A
E
T
к
a
K
b
c
d
e
ace
a
a → b → c → d → e → c → a
I
δQ
T
= 0.
a → b → c → d → e e → c → a
T = const
H
δQ = 0
δQ = dU +p dV
H
dU = 0
I
p dV = 0,
Z
a→b→c→d→e
p dV =
Z
a→c→e
p dV.
AaceE
AabcdeE
ace
abc cde
V
2
pV
3
− (RT + pb) V
2
+ aV − ab = 0.
T
T p = const
V
p = const p V
p =
RT
V −b
−
a
V
2
.
V ≈ b+RT/p
p
p = const
T
k
K
T
c
V
c
p
c
a b
K
∂p
∂V
T =T
c
= 0,
∂
2
p
∂V
2
T =T
c
= 0,
p = p(V, T
c
)
p = p
c
V = V
c
V
c
= 3b, p
c
=
a
27 b
2
, T
c
=
8a
27 Rb
.
V
c
ν V
c
= 3νb
K
c
=
R T
c
p
c
V
c
a b
K
c
=
8
3
= 2, 67.
8/3 H
2
O
K
c
= 4, 46 O
2
K
c
= 3, 42
bcd
ab de
∂p
∂V
T
< 0.
ace
ab de ab
de
ab
de
p =
p(V, T )
U = U(V, T )
U = U(T ) = C
v
T.
C
v
U = U(V, T )
(∂U/∂V )
T
T dS = dU + p dV,
δQ = T dS
V T
T = const
dS = (∂S/∂V )
T
dV, dU = (∂U/∂V )
T
dV.
dV
∂U
∂V
T
= T
∂S
∂V
T
− p.
T dS = d(T S) − S dT.
F = U − T S,
dF
dF = −S dT − p dV.
F (V, T )
∂F
∂T
V
= −S ,
∂F
∂V
T
= −p.
f(x, y)
∂
2
f/∂x ∂y = ∂
2
f/∂y ∂x.
F (V, T )
∂
2
F
∂V ∂T
=
∂
2
F
∂T ∂V
.
∂S
∂V
T
=
∂p
∂T
V
,
∂U
∂V
T
= T
∂p
∂T
V
− p.
p = p(V, T )
ν
∂p
∂T
V
=
R
V −b
.
∂U
∂V
T
=
a
V
2
.
T = const
U(V, T ) = −
a
V
+ f (T ),
f(T )
V → ∞
f(T ) =
C
v
T
U(V, T ) = C
v
T −
a
V
.
T V
U = const T = const
U = U(V, T )
dV
C
v
dT +
a
V
2
dV = 0,
dT
dV
= −
a
C
v
V
2
< 0.
(∂T/∂V )
U
< 0
G = F + pV = U − T S + pV,
dG = −S dT + V dp.
(∂U/∂V )
T
= 0
