Question

analysis of a mixture of carbonate and bicarbonate:

I did an experiment where 2.306g of unknown was diluted with distilled water to 250ml. Then 3 25mL samples of this unknown were titrated with .0663 M HCl and end point volumes were: 41.12mL, 41.00mL and 40.99mL.

Then 3 more 25mL samples were taken, 50mL of .0664 M NaOH and 10mL of 10wt% BaCl2 were added, and the mixture was again titrated with .0663 M HCl to give end point volumes of: 26.59mL, 26.41mL and 26.69mL.

provided equations:

(HCO3)- + H+ --> H2CO3
(CO3)2- + 2H+ --> H2CO3
(HCO3)- + (OH)- --> (CO3)2- + H2O
(Ba)2+ + (CO3)2- --> BaCO3(s)

Knowing this I'm suppose to calculate total alkalinity, moles NaOH initially added, moles NaOH reacted with HCl, moles and mass(g) NaHCO3, moles and mass(g) Na2CO3, and wt/wt% of NaHCO3 in unknown and wt/wt% of Na2CO3 in unknown.

I've tried doing it a million times now and I have no idea if I'm doing it correctly. If someone could explain how to do this that would be great. Thank you!