- , , . . :
, ( ) .
, , , .
, .
.
, .
() , .
, . :
1) , .. . (Q, ).
2) , - . (A, ).
: I- , .. , , , .
I- :
) :
dQ =dU + dA,
d , d .
) :
Q = A + DU,
DU = U2U1 .
U , . , . , , . , , , . ( ), :
dA = dV,
, dV , V,
= DV.
, , . :
) - :
V = nRT.
) - :
U = f (T)
(=const)
V = nRT=const, V = const 1V1 = 2V2 , P1 P2,V1 V2 .
|
|
U = f (T) = const, Þ DU = 0, Q = A = DV,
Q = A = nRT ln(V2/V1) = nRT ln(P1/P2)
(V=const)
: = const =
, DV = 0, : A = DV = 0 Þ Qv = DU.
Qv = DU = nCvD,
v . Cv = (3/2)×R12,47 /(×), (, 2): Cv = (5/2)×R 20,78 /(×); : Cv = 3R=24,93 /(×).
(=const)
: = const =
D = DU + pDV,
Q = DU + A, Q = DU + pDV, , , , .
Q = D = nCD,
. 1 : v = R
(dQ =0).
: =const, = , g = /v.
: A = DU, = -DU = nCv(1-2)
, : - (1 = =1,013×105 = 760 . .), - (H×), - 3 [13 = 103 3 () = 106 3()], - (00 = 273).
(..) , = 1 = 101325 , = 273 ; - = 1 = 101325 , = 250 = 298 .
.
, - ( , , , ..).
, ( ), , , . :
QV = DU
Q = D
:
D =DU + DnRT
Q= QV + DnRT,
Dn - , , ..:
Dn = Sn() - Sn(),
Sn.() ; Sn.() ( ).
, .
, . . , , D DU, . , , , , . . , , : , . :
|
|
= -QP, = -QV.
. , ( ). ( = 1 = 1,013×105, =298 ). D0 ( 0 ).
. () + 2() = 2() ΔHº = 393,5 . , 163960 ?
n(C) =
m(C) = n(C)×M(C) =416,67×12 = 5000 .
, :
I . , :
D- = Sn D - Sn D
, :
a + b Þ + dD
D0- = (aD0.A+ bD0.B) - (D0.+ dD0.D).
1 ( 2 2).
. :
C25OH () + 3 () = 3COOC25 () + 2 ()
250, :
: DH0.(C25OH()) = -1366,9 /, DH0.(3()) = -873,8 /, DH0.(3COOC25()) = -2254,2/, DH0.(2()) = 0 /. | . C25OH () + 3 () = = 3COOC25 () + 2 () : |
DH0- -? |
DH0- = DH0.(C25OH()) + DH0.(3 ()) - DH0.(3COOC25()) -
- DH0.(2 ()) = -1366,9 -873,8 - (-2254,2) 0 = 13,5 .
II . , :
D- = SnD - SnD
, :
a + b = + dD
D0-=(D0.+ dD0.D) - (aD0.A+ bD0.B).
1 , , .
. .
. , 250:
F2O3 () + 3 () = 2Fe () + 32 ()
:
DH0.(Fe2O3()) = -821,32 /; DH0.(O()) = -110,5 /; DH0.(Fe()) = 0 /; DH0.(O2 ()) = -393,51 /. | . F2O3 () + 3 () = 2Fe () + 32 () , : |
DH0- -? |
DH0- = 2DH0.(Fe()) + 3DH0.(O2()) -DH0.(Fe2O3()) - 3DH0.(O()) = -3×393,51 + 821,32 + 3×110,5 = -27,71 .