HELP?? Please!!!?

Question

Indicate the concentration of each ion present in the solution formed by mixing the following.
(a) 26 mL of 0.100 M HCl and 10.0 mL of 0.220 M HCl
H+ : _____ M
Cl- : ______ M

(b) 15.0 mL of 0.300 M Na2SO4 and 20.2 mL of 0.100 M NaCl
Na+ : ____ M
SO42- : ____ M
Cl- : ____ M

(c) 3.50 g of KCl in 60.0 mL of 0.306 M CaCl2 solution (assume that the volumes are additive)
K+ :_____ M

Ca2+ : _____ M
Cl- : _____ M

Answer 1

Principle: Sum(ViMi)= VfMf
This is a mass conservation equation.
In a, we have two sources of HCl, so
V1=26, M1=0.1
V2=10, M2=0.22
Vf= 36, Mf= (2.6+2.2)/36 =0.133 M HCl
Since HCl totally dissociates in water, this is conc of each ion.

In b, we have two sodium salts. Each supplies a different cation. For the sodium ion:
V1=15, M1= 0.6 M Sodium (sulfate)
V2-20.2, M2=0.1 M Sodium (chloride)
Vf=35.2 Mf= (15x.6+20.2x0.1)/35.2= (solve)
For the sulfate
V1=15, M1=0.3
V2=20.2,M2=0
Vf=35.2, Mf= 4.5/35.2=(solve)
For the chloride,
V1=15,M1=0
V2=20.2,M2=0.1
Vf=35.2, Mf= 2.02/35.2=(solve)

(c) is pretty much the same except that each salt adds chloride and one of the two anions. Should be no sweat.