: δQ = dU + δ,
dU ( ) , δA , δQ . δ δQ .
, . , , , . , .
, .
, δQ >0; , δQ < .
, δ > , , δ < .
, , Δ U = 0, A = Q, .e. , , , .
28. .
, , , dl, δ = Fdl = pSdl = pdV, S .
, V1 V2: |
, . ,
. , ( ) .
(,V). δ = pdV , V1 V2.
(p,V) -, . .
29. .
, , 1 1 . /( ) | |
, , 1 1. /( ). | |
: |
( ) (cv ) (p ), .
|
|
30. .
δ Q = dU + δ A, δ A = pdV
μ = , 1 : .
V = const δ .
Cv 1
1.
dUμ = i/2RdT,
31. . .
= const,
(
, V, ) Cv.
- pVμ = RT
= const,
p = V + R
p V- .
, , .
,
.
. , , .
32. (V const).
(p,V) , ( ). 2-1 , 2-3 .
(δ = pdV = 0) , , (δQ = dU). dUμ = CvdT, :
33. ( = const).
(p,V) ( V). V1 V2 :
. pV = RT, V2-V1= mR/pμ (T2 T1),
: R 1 1 .
34. ( = const).
(p,V) . - (pV = const).
= const , , δQ =δ A, , , .
, , , , .
35. (δQ = 0).
, ( δ Q = 0).
|
|
( ), , , , . .
, δ A = -dU. δ = pdV dU=m/μ CVdT,
pdV = m/μ CVdT (1). , pV = m/μRT
pdV + Vdp = m/μRdT (2). (2) (1) :
. ln Vγ+ ln p = In const, . |
- pV = RT, : |
(p,V) . ( ) , (pV = const). , 1-3 , .
36. .
δ A = -dU, δ =- CvdT.
V1 V2, T1 2
, - pV = RT.
1-2 ( ) , . , , .
37. ( = const).
, ( = const) .
, , .
pVn = const
.
.
n | ||
= 0 | n = | |
=∞ | n = 1 | |
C=Cp | n = 0 | |
C=CV | n =∞ |
, dT = 0, δ Q≠0.
, δ Q= 0, dT ≠ 0
( ) , , , . (,V)- , 1-2 , 2-1 .
1 ( 1 a2V2V11) : 1 >0. 2 ( 2b1V1V22) : 2 < 0.
, :
= 1 + 2
, , , . (, ). , Q, , , .
, A = pdV > ( ()).
,
= pdV < ( ()).
( ). ( ).
|
|
39. .
, , . Q = ΔU + = , .. , , . Q1, () Q2, Q= Q1- Q2.
, , , , :
40. .
, , . , , , . , , .
, () (- , ..). .
41. .
δ Q, , , ( δ Q
).
, δ Q .
, , , .
S , δ Q/T:
.. δ Q = dU + δ TdS = dU + δ A, δ = TdS -dU= d(TS) - SdT -dU = -d(U - TS) - SdT = -dF - SdT
F =U-TS .
42. .
ΔS = 0; ΔS > 0.
: ( ) ( ). | ΔS≥0 |
dS δ Q , . δ Q>0 dS>0, δ Q<0
dS < 0.
, (S = const).
δ Q = TdS = 0, dS = 0 S const, .
, 1 2.