2.E(xred):electrode potential at standard condition when all solutes are IM and all gases are at I atm 3.A,H the standard molar enthalpy change of a reaction 六、 1、Solution: H2S+2H*+S2 K=KK-(HIs2Y[HSF[0.12[S210.1=1.0x10x1.0x103→[S2= 1.0x1022mol. Kp9(ZnS)=S2]Zn2+]=1.0x102x0.01=1.0x1024 Zn2 4CN ← Zn(CN)42- First initial conc.0.01/2 1.0/2 0 Second Initial Conc.0 (1.0-0.01x4)/2 0.01/2 Atequi. (1.0-0.01x4)/2+4x 0.01/2-x [0.01/2)x/[(1.0-0.04)/2+4x*x=KrZn(CN)42=5.0x1016 →[Zn2=x=1.88x1018moL [S2-]=Km°(ZnS)/[Zn2=1.0x1024/1.88x1018=5.3x107 H2S+2H+S2 0.1 y 5.3x107 第2页 2．E(ox/red) Θ: electrode potential at standard condition when all solutes are 1M and all gases are at 1 atm 3. ΔrHm Θ: the standard molar enthalpy change of a reaction 六、 1、Solution: H2S ↔ 2H+ +S2- Kθ =Ka1 θ Ka2 θ =([H+ ] 2 [S2-])/ [ H2S ]=[0.1] 2 [S2-] / 0.1=1.0x10-8 x1.0x10-5 → [S2-] = 1.0x10-22mol.l-1. Ksp θ (ZnS) = [S2-][Zn2+ ] = 1.0x10-22 x0.01=1.0x10-24 Zn2+ + 4CN- ↔ Zn(CN)4 2- First initial conc. 0.01/2 1.0/2 0 Second Initial Conc. 0 (1.0-0.01x4)/2 0.01/2 At equi. x (1.0-0.01x4)/2 + 4x 0.01/2 - x [(0.01/2)-x] / [(1.0-0.04)/2 + 4x]4 *x = Kf [Zn(CN)4 2-] =5.0x1016 → [Zn2+] = x =1.88x10-18 mol·L-1 [S2-]= Ksp θ (ZnS) / [Zn2+]=1.0x10-24 /1.88x10-18 =5.3x10-7 H2S ↔ 2H+ + S2- 0.1 y 5.3x10-7 第 2 页