I REALLY need help with these problems for analytical chemistry, so if someone w

Question

I REALLY need help with these problems for analytical chemistry, so if someone who is REALLY good at analytical chemistry could help, I would greatly appreciate it. I would also greatly appreciate it if all the questions could be answered, not just one.

11. These compounds, in these concentrations are combined in an aqueous solution.

                        0.025 M K2SO4; 0.005 M MgCl2 and 0.015 M Al(NO3)3

(a) Write the charge balance equation for this solution.

(b) Show by calculation that the charge balance equation is true, for these ions in these concentrations.

12. A solution contains acetic acid CH3COOH , sodium acetate NaC2H3O2 and CuCl2. The copper(II) ion forms a soluble ion pair 1:1 with acetate ion (CuC2H3O2+), and also a soluble complex (2 acetate ions to 1 Cu2+ ion: Cu(C2H3O2)2).   Write the mass balance equation for the acetate ion in this solution.

13. (a) A solution is prepared from NaHCO3 (0.200 M) Write the proton balance equation for this solution:

(b) Calculate the pH of the solution in part (b).

14. A buffer is prepared from "not-so-weak" maleic acid (0.0350 M) and the sodium salt of its first dissociation product, sodium malate (0.0500 M)   (Ka1 for maleic acid is 1.20 x 102; the second deprtonation is not a factor. Show by calculation what the expected pH is for this buffer.

Explanation / Answer

When thee compounds are mixed together fowwing equilibrium will exist.

K2SO4 <==> 2K+ + SO4^2-

H2SO4 <==> H+ + HSO4^-

HSO4^- <==> H+ + SO4^2-

MhCl2 <==> Mg^2+ + 2Cl-

HCl <==> H+ + Cl-

Al(NO3)3 <==> Al^3+ + 3NO3^-

HNO3 <==> H+ + NO3^-

(a) Charge balanced equation :

2[K^+] + 4[H+] + [Mg^2+] + [Al^3+] = 2*[SO4^2-] + [HSO4^-] + 2[Cl-] + 4 [NO3^-]

(b) total positive charge = 2*1 + 4*1 + 2+ 3 = 11

toal negative charge = 2*2 + 1 + 2*1 + 4*1 = 11

total positive charge = total negative charge. So, the equation is charge balanced.

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