Question

在50ml0.1mol/lAgNO3溶液中加入密度为0.93g/cm3,质量分数为0.182的氨水30ml后,加水稀释到

Answer 1

0.93g/cm3,质量分数为0.182的氨水30ml:

n(NH3)=30*0.93*0.182 /17=0.30mol

50ml0.1mol/lAgNO3:

n(Ag+)=0.005mol

则总银浓度:c(Ag)=0.005/0.1=0.05mol/L

游离的氨浓度c(NH3)=(0.30-0.005*2)/0.1=2.9mol/L

查表:累积稳定常数:β1=10^3.40 β2=10^7.40 数据来自北师大版《无机化学》

[Ag+]= c(Ag)* 1/ { 1 + β1*[NH3] + β2* [NH3]^2 }

=0.050 * 1 /{ 1 + 10^3.40 *2.9 + 10^7.40 *2.9^2}

=2.4*10^-10(mol/L)

[Ag(NH3)+]= c(Ag)* { β1*[NH3] }/ { 1 + β1*[NH3] + β2* [NH3]^2 }

=0.050 * 10^3.40 *2.9 /{ 1 + 10^3.40 *2.9 + 10^7.40 *2.9^2}

=1.7*10^-6(mol/L)

[Ag(NH3)2+]= c(Ag)* { β2* [NH3]^2 }/ { 1 + β1*[NH3] + β2* [NH3]^2 }

=0.050 * 10^7.40 *2.9^2 /{ 1 + 10^3.40 *2.9 + 10^7.40 *2.9^2}

=0.050(mol/L)