2.2Hf(aq)+2e→H2-Ag+r-e→AgI(+) ()Ag(s)l AgBr(s)IH'(aq)Ha(g),Pt(+) 六 1.answer CaCO3 (s)=Ca"(aq)+CO(aq) First initial 0.05 0.25 Second initial 0.0 0.20 At equilibria 0.20+x x0.20+x）=Kp°(CaC0)=2.8x109=x≈1.4x10molr M(CaC0g)=(0.05-x)Fw(CaC0)x200=(0.05-x)x100x200/1000=1.0g 2、Answer: Ag'+e=Ag E(Ag'lAg) Fe+e=Fe2+E(Fe/Fe2) AgBr=Ag*+Brsp (AgBr)=[Ag] Ag+Br=AgBr+e Since E=E(+)-E(-)=E(Fe/Fe2)-E(Ag"/Ag) S0,0.700=0.771-0.0592/1lg(1/MAg7 0.700=0.771-0.0592/1lg(/Kp°(AgBr) Kp°(AgBr)=5.04x10 3、Answer: CaS04=Ca2++S042 BaSOa=Ba2+SO 0.01 X 0.01y Kp°(CaS0)=0.01x=9.1x109 Kp°(BaS0)=0.01y=1.8x100 x=9.1x104 y=1.8x10 so,BaSO precipitates first. When CaSOstarts to precipitate. Ba21=Kp9(BaS04)/[S042=1.8x100/9.1x104=1.98x107mol. 4、Answer: 2HCI + 1/202(g) C12(g+ H20(g) Initial(mol）) 0.02 0.08x0.2 0 0 At equilibria 0.02-2x 0.016-x/2 第2页 2. 2H+ (aq) + 2e → H2 (-); Ag + I- - e → AgI (+) (-) Ag (s) ⎢AgBr(s) ⎢⎢H+ (aq) H2(g), Pt (+) 六、 1. answer CaCO3 (s) = Ca2+(aq) + CO3 2-(aq) First initial 0.05 0.25 Second initial 0.0 0.20 At equilibria x 0.20 + x x(0.20 + x) = Ksp Θ (CaCO3) = 2.8x10-9 ⇒ x ≈ 1.4x10-8mol.l-1. M(CaCO3) = (0.05 – x) Fw(CaCO3) x 200 = (0.05-x) x100 x200/1000 = 1.0g 2、Answer: Ag+ + e = Ag EΘ(Ag+ /Ag) Fe3+ + e = Fe2+ EΘ(Fe3+/Fe2+) AgBr = Ag+ + Br- ⇒ Ksp Θ (AgBr) = [Ag+ ] Ag + Br- = AgBr + e Since E = E(+) – E(-) = EΘ(Fe3+/Fe2+) - EΘ(Ag+ /Ag) So, 0.700 = 0.771 – 0.0592/1 lg(1/[Ag+ ] 0.700 = 0.771 – 0.0592/1 lg(1/ Ksp Θ (AgBr)) Ksp Θ (AgBr) = 5.04x10-13 3、Answer: CaSO4 = Ca2+ + SO4 2- 0.01 x Ksp Θ (CaSO4) = 0.01x = 9.1 x10-6 x = 9.1 x10-4 BaSO4 = Ba2+ + SO4 2- 0.01 y Ksp Θ (BaSO4) = 0.01y = 1.8 x10-10 y = 1.8 x10-8 so, BaSO4 precipitates first. When CaSO4 starts to precipitate, [Ba2+] = Ksp Θ (BaSO4) / [SO4 2-] = 1.8x10-10/ 9.1x10-4 = 1.98x10-7mol.l-1 4、Answer: 2HCl + 1/2O2(g) Cl2(g)+ H2O(g) Initial(mol) 0.02 0.08x0.2 0 0 At equilibria 0.02 – 2x 0.016 – x/2 x x 第 2 页