物理化学下期末试题

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

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