k1=A1·exp(?
Ea,1RT
)
k-1=A-1·exp(?Ea,?1RT)
)
k2=A2·exp(?Ea,2RT代入上式比较得:Ea=Ea,1+Ea,2-Ea,-1
五、计算题(36分) 1.(20分)(1)电极反应:
(-)Pb(s) –2e + 2Cl-(aCl-) → PbCl2 (s)
(+)Hg2Cl2 (s) + 2e → 2 Hg (l) + 2Cl-(aCl-)
电池表示式:
Pb(s) + PbCl2 (s)∣Cl-(aCl-)∣Hg2Cl2 (s) + Hg (l) (2)W = -Δ rGm = z·E·F
= 2×96500×0.5357 = 1.034×102(kJ·mol-1)
可逆电池作功最多,最多能作功1.034×102KJ·mol-1 (3)Δ rHm = -z·E·F + z·F·T(
?E)p ?T = -103.4×103 + 2×96500×298×1.45×10-4 = -95.1(kJ·mol-1)
Δ rSm = z·F(
?E)p ?T = 2×96500×1.45×10-4
= 28.0(J·K-1)
(4)QR =T·Δ rSm
= 298×28.0
= 8.314×103(J) 2.(16分)(1)初始浓度均相等的二级反应:
y?ak2t 1?y ∴k2(298K)=
0.391?=0.107mol-1·dm3·s-1
1?0.390.01?6000.551?k2(308K)==0.203·dm3·s-1
1?0.550.01?6006 / 7
(2)据阿仑尼乌斯公式:
lnk2(308K)Ea11?(?)
k2(298K)R298308 ∴ Ea=48.87KJ·mol-1 lnk2(298K)Ea11?(?)
k2(288K)R288298 k2(288K)=0.054 mol-1·dm3·s-1 ∴
y1?y?0.01×0.054×600 y=24.47% (3)二级反应t11/2?ak 2 =
10.01?0.107
=934.58s 7 / 7