, : 1. , ; 2. , , .
, - . , . Q, Δ U.
.
∆ X
|
Q
Q , .
∆ X, D V = ∆ X × S. S . , F.
, , , . . 1.
Q = D U + A. (1)
= D V, , , D V .
( ).
. (V = const; Δ V = 0). .
D V, D V = 0, :
D U = QV. (2)
, (V = const) : = 0; QV = ∆ U.
. (P = const). = const, , , , , = 1 .
:
Qp = U 2 U 1 + (V 2 - V 1) Qp = U 2 U 1 + .
Qp = (U 2 + V 2) - (U 1 + V 1); (3)
Qp = ∆ H = ∆ U + D V.
(3) , , , - :
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H = U + V (/). (4)
, , (Qp = ∆ H), .
, , , .
, ( ) , . ∆ 298 :
() - (0 /); - (1,828 /);
Sn () - (0 /); Sn () - (-2,1 /);
() - (-17,6 /); () - (0 /);
S () - (0 /); S () - (0,38 /);
- . , . , , , , H2SO4 , ..
.
- .
.
, , . , , ∆ H, ∆ H , , : () () - , () , () . , , , (), S () .. , .
,
2() + 1/2 2() > 2(), ∆ H.
, , .
∆ H () 1 (2 ) , 1/2 (16 ) 1 (18 ) .
∆ H ∆ U. Qp = ∆ H Qp = D U + D V , ∆ H D U ():
∆ H - D U = D V.
, ( ), D V ∆ H @ D U.
, ∆ n, , D V ∆ nRT,
∆ H - D U = ∆ nRT,
∆ n .
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22 ()+ 5\22 () = 2() + 2 2() ∆ n = - 1,5 ;
Cu()+4HNO3() = 2NO2() + Cu(NO3)2() +2 H2O() ∆ n = + 2,0 ;
N2 () + 3H2 () = 2 NH3() ∆ n = - 2,0 .
, (∆ n = 0), ∆ H = D U.
1 , 298 = 105 ( 1 .).
, .
:
½ 2() + ½ I2 () = HI () ∆ H 0298 = 26,04
2() + I2 () = 2HI () ∆ H 0298 = 52,08
1 HI() (∆ H 0298 HI), .
HI, 2 (∆ H 0298 HI).
:
() + 3/2 2() + () = 3()
() + 2() = 3()
1 3() (∆ H 298 3), .
, 1 3 () 2().
1 2().
, :
22() + 5/22() = 2 2() + 2()
∆ H 0 1 .
, .
: , .
, , ( ), , , .
, .
, ( ). , , 2. D 0298 :
() + 2() = 2() D 0 = -395 ;
() + ½ 2() = 2() D 0 = -284 .
, :
() + ½ 2() = () D 0 = -111 .
, , , .
1- 2- :
1- : , .
D 0 298 = S (n iD º298 ) - S (n iD 298). (5)
= const.:
Cu() + 4HNO3() = 2NO2() + Cu(NO3)2() + 2 H2O()
D 0298
/ 0 -174 33 -305,3 -286
D 0298 = å(D 298 ) - å(D 298 ) = [2×33 + (-305) + 2(-286)]
[4(-174) + 0] = -115
, D 298 ( ), (.1).
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Δ ,
/ ∆ H >0
Δ
Δ
∆ H < 0
Δ
.1.
2- : , .
D 0 298 = S (n iD 0 298) - S (n iD 0 298). (6)