大二化學題目

Question

如何利用18M之HCL溶液配製100ml5M之HCL溶液

已更新項目:

200g的水中mgco3(s)的溶解度為6.85x10-(負)4(g)試求ksp=?

Answer 1

最佳解答

(1) 所需的 HCl 摩爾數 = 5 x 0.1 = 0.5

所需的 18M HCl 溶液 = 0.5/18 = 0.0278 dm3 = 27.8 cm3

所需的水 = 100 - 27.8 = 72.2 cm3

(2) MgCO3 摩爾質量 = 24.1 + 12 + 3 x 16 = 84.1 g/mol

即 6.85 x 10-4 g 含有 8.145x 10-6 摩爾.

所以, 溶液中:

[Mg2+] = 8.145x 10-6 M

[CO32-] = 8.145x 10-6 M

Ksp = [Mg2+][CO32-] = 6.634 x 10-11 M2

2009-12-21 10:29:10 補充：

(2) 修改:

[Mg2+] = 8.145x 10^-6 / 0.2 = 4.073 x 10^-5 M

[CO32-] = 8.145x 10-6 / 0.2 = 4.073 x 10^-5 M

Ksp = [Mg2+][CO32-] = 1.659 x 10^-9 M^2

參考資料： Myself