黑龙江省分析化学真题及答案

pH=8.00

S2分配系数

=[S2-]/{ [H2S]+[HS-]+[S2-]}

= ka 1 * ka2 /{[h+]^2+[h+]* ka 1+ka 1 * ka2 }

=(1.3*10^-7 *7.1*10^-15) /{ (10^-8.00)^2 + (10^-8.00)*(1.3*10^-7) +(1.3*10^-7 *7.1*10^-15)}

=6.6*10^-7

Ag+的分配系数

=[Ag+]/{[Ag+]+[Ag(NH3)+]+[Ag(NH3)2+]}

= 1/{ 1+β1 *[NH3]+β2*[nh3]^2}

=1/ {1+10^3.24 *0.01 +10^7.05 *(0.01)^2}

=8.8*10^-4

Ag2S & lt= = & gt2Ag+ +S2-

2s s

[Ag+]=2s *8.8*10^-4

[S2-]= *6.6*10^-7南部

ksp(ag2s)=[ag+]^2 *[S2-]=(2s *8.8*10^-4)^2 *(s *6.6*10^-7)=2.0*10^-49

s=4.6*10^-13摩尔/升