0.408 g of an unknown diprotic acid is dissolved in about 60 mL of water in a beaker. The solution is transferred to a 100.00 mL volumetric flask, which is then filled up to the mark. The solution is mixed by inverting multiple times.
25.00 mL of this solution is then transferred to an Erlenmeyer flask for the titration. What mass of the diprotic acid is in the 25.00 mL that is transferred? Provide your answer to the correct number of significant figures.