四、计算题
1. 解:已知KfΘ(Cu(NH3)4)2+)=2.30×1012, [Cu(NH3)4]2+ + 2e-===Cu + 4NH3
EΘ(Cu[NH3)4]2+/Cu) == EΘ(Cu2+/Cu)—0.O592/2lgKfΘ(Cu (NH3)42+) ==[0.3394---0.0592/2lg(2.30×1012)]V===-0.0265V 对于1.0mol?L-1氨水,溶液中
C(OH)=KΘ[(NH3) ×c(NH3)]1/2 ==(1.8×0.10-5×0.10 mol?L-1)1/2 ===4.2×10-3 mol?L-1
EΘ(O2/OH-)== EΘ(O2/OH-) + 0.0592/ 4 (lgp(O2)/pΘ)/ 解2. CuCl + e- ===Cu +2Cl
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EΘCuCl2-/Cu == 0.52V +0.059 V lg 1/K稳Θ ==0.20V 浓盐酸中,[H+]==[Cl-]==12 mol?dm-3 ,设 [CuCl- ] ==1 mol?dm-3 EcuCl2-/Cu == 0.20 V +0.059 Vlg [CuCl2- ]/[Cl-]2 =0.20v +0.059 Vlg 1/122 ==0.073 V
E H+/H2 ==0V +0.059 Vlg[H+] ==0.059Vlg12 ==0.064 V
计算结果表明EcuCl2-/Cu > E H+/H2 ,铜不能从浓盐酸中置换出氢气.
Et?10?pM??10??pM?spM?100%?CKMY