posted by Jayd .
Calculate the sodium ion concentration when 45.0 mL of 2.5 M sodium cabonate is added to 30.0 mL of 1.0 M sodium bicarbonate.
mols Na2CO3 = M x L. Mols Na^+ = twice that.
mols NaHCO3 = M x L. Mols Na^+ = 1 x that.
Total Na = sum of the two.