T = const | |
p = const | |
V = const | |
d Q =0 |
, , , , . , , , , (), ( ) ..
, Q, A D U:
Q = A + D U, (7.1)
D U , . , A = D U ( ).
, D U, . , , , , , , , , , , .
, .. , . , . , , , .
, (). 1 1 1 (1 = 1 × = 1 ×2/2). (). 1 , 1 1C. 1 = 4,184 4,2 . - : 1 = 1000 , 1 = 1000 .
3. . , ., , . (D H), D H = D U + P D V . , P D V = A , D H = Q ( ). , D H. , () D H < 0, () D H > 0. (!) (Q > 0 Q < 0 ).
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( ) , ( , 1836)
:
C() + O2(.) = CO2(.) D H 1 = 393,5
() + 1/2 O2(.) = CO(.) D H 2 = 110,5
(.) + 1/2 O2(.) = 2(.) D H 3 = 283,0
CO2 , , CO (D H 1 = D H 2 + D H 3). :
rot , (7.2)
i .
, , .
, , , ..
, (7.3)
,
D H 1 + D H 2 + D H 3 + D H 4 = 0, (7.4)
, , . .
, . , :
H2(.) + O2(.) = H2O2(.) D H 1 =?
:
H2(.) + 1/2O2(.) = H2O(.) D H 2 = 285,8 ,
H2O2(.) = H2O(.) + 1/2O2(.) D H 3 = 98,2 .
, :
D H 1 = D H 2 D H 3 = 285,8 + 98,2 = 187,6 (/).
, , . D Hf 298, =298,15 (25C) p = 101,325 (1 ), .. . ( !)
D Hf 1 :
Ca (.) + C () + 3/2O2 (.) = CaCO3 (.) D H 298=1207 /.
, . , ( ) :
H2 (.) + 1/2O2 (.) = H2O (.) D H 298 = 285,8 /,
H2 (.) + 1/2O2 (.) = H2O (.) D H 298 = 241,8 /.
H2O (.) = H2O (.) D H 298 = 44,0 /.
. , D H = 0 , , , , , :
3/2O2 (.) = O3 (.) D H 298 = 142 /,
C () = C () D H 298 = 1,90 /.
, , :
D H () = SD Hf () SD Hf (). (7.5)
:
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4Al (.) + 3PbO2 (.) = 2Al2O3 (.) + 3Pb (.). (a)
:
2Al (.) + 3/2O2 (.) = Al2O3(.) D H 298 = 1669,8 /, (b)
Pb (.) + O2 (.) = PbO2 (.) D H 298 = 276,6 /. (c)
, : , , , .
4Al (.) + 3O2 (.) + 3Pb (.) + 3O2 (.) = 2Al2O3 (.) + 3PbO2 (.).
D H 298(a) = 2×D H 298(b) 3×D H 298(c).
4Al (.) + 3PbO2 (.) = 2Al2O3 (.) + 3Pb (.).
D H 298(a) = 2×(1669,8)3×(276,6) = 2509,8 .
, , , . . , . D H :
4Al(.) + 3PbO2(.) = 2Al2O3(.) + 3Pb(.).
Δ Hf 298 0 3×(276,6) 2×(1669,8) 0.
D H 298 = 2×(1669,8)3×(276,6) = 2509,8 .
. ( ) . . , , .. . , (, ) (, ). , - .
, . S . , , , , - , . .
, , : (, 1850). , , . . , . , , , .
, , . , . .
. , .. (D S > 0). , , . , (, 1896). . , , . ( ) ( ):
D H = D S×T, (7.7)
D H . D S < D S < D S , .. , , . , , , . , H2O , , ; , , ..
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( ), , 0 lim D S =0 ( T0).
/×. , ( ), .
,
D = D H /D T, (7.8)
, , () . , 100 , , . cp.
S 298 . , D Hf S 298 > 0, . , :
D S () = S S () S S (). (7.9)
D S > 0 , D S < 0 .
D S . D S > 0 , , , , , . D S < 0 , , , .
, D S 298 ().
4Al (.) + 3PbO2 (.) = 2Al2O3 (.) + 3Pb (.)
S 298 4×28,32 3×76,6 2×50,99 3×64,89
D S 298 = 2×50,99+3×64,89 4×28,32 3×76,6 = -46,4 /.
, , .
? , : .
5. . . . , ( - ) D G.
:
D G = D H T D S, (7.10)
T . 1 Δ G /. . , :
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D G () = SD G () SD G (). (7.11)
D G < 0. D G > 0, . :
4Al (.) + 3PbO2 (.) = 2Al2O3 (.) + 3Pb (.).
Δ G 298 0 3×(219,0) 2×(1576,5) 0.
Δ G 298 = 2×(1576,5)3×(219,0) = 2496 .
D G . Δ H Δ S, D G = D H T D S:
D G 298 = 2509,8 298,15 ×(0,0464 /) = 2496 .
, . Δ G , . . (. 8).
8
D H < 0, D S > 0 | . , . |
D H < 0, D S < 0 | , . . |
D H > 0, D S > 0 | , . . |
D H > 0, D S < 0 | . . |
D G > 0, , , . D H D S , - . D S T. , , T D H /D S .
D G = 0, , .. D G (. ).
, (, ) , , , , .
.
? . , .
1. . . .
() , v :
; ; ; , (9.1)
D n ; t ; D c . , .
. 15. , u () .
. 15. .
( ) , , (D n) (Dt) (S):
; ; (9.2)
(), 1865 . .. . : , , (aA+bB=dD), :
, (9.3)
k , 1 /; a b ; .
, 2 + = 2 :
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v = k CA 2 CB. (9.4)
, . (9.3) . , . , + 2=2
. (9.5)
PO 2. k .
. : I. ; II. .
I. 1) , :
2 = 2 ;
C3COOC2H5 + H2O = C3COOH + C25OH ;
2NO + Cl2 = 2NOCl .
, ;
2) . , (9.5) , (9.4) . , .
II. 1) . , , , , v 1 < v 2.
2KOH + Cl2 KClO + KCl, 6KOH + Cl2 KClO + 5KCl;
2) D. , , , .. , . , , , ;
3) . , .
2. . . . .. - , 10 ., 2-4 ( -):
. (9.6)
g , 21=10 , 10 (9.6) . (9.7):
, (9.7)
k 0 . . 16.
:
ln k = Ea / RT + ln k 0. (9.8)
, , , k 0 , , 1/→0. , .
, , , . , ( ,
). , , .
. 16. : 1 ; 2 . , , .
. , , , , . , , . , . 1000 /, , , . . , = 0 , , , .
3. . , , . , . , . . () , (. 16).
1. , (DG<0).
2. , , .
3. .
4. , .
5. , . .
. . , , . . , . +=AB; +=[]; []+=AB+.
, , . , , 40-350 .
4. . () () . . :
2KClO3 = 2KCl + 3O2.
, , . , , . 14, , . , :
32 + N2 ⇄ 2N3.
( ), ( ). : ⇄.
() () :
. (9.9)
. (9.10)
, . (9.9, 9.10), :
. (9.11)
. . , , , , .
, , . : . . .
, . , . , ( ), .. . : , , ; -: , , . .
. - , , .. .
, . .
, , - ;
- .
. , , . - , , .
: D H = 92 /. , .
- ; .
, , 2 , . , , , , . , : . , , . : D G =0, .
:
D G = RT ln K. (9.12).
: DG (Kp), , . DG (Kp), . (9.9) DG (), .
, (DG) ( , Kp).