Analytical Chemistry
posted by Kevin on .
Determine the pH of a solution that is generated when 2.623 g Na3PO4 is added to a 100mL of 0.0800 M H3PO4.

I would use
k1k2k3 = (H^+)^3(PO4^3)/(H3PO4)
Plug in for PO4^3 and H3PO4 and solve for (H^+) then convert to pH. 
I use the Given concentrations? and solve for [H3O]?

right. mols Na3PO4 = grams/molar mass and M = mols/L solution.
H3PO4 is given.
Solve for H^+ and convert to pH.