Question

What mass of oxalic acid dihydrate, H2C2O4•2H2O, is needed to make a 0.357 M solution of oxalic acid in a 250.0mL volumetric flask?

Answer 1

Molarity is expressed as the number of moles of solute per volume of the solution. The mass of oxalic acid dihydrate needed for the solution is calculated as follows:

Amount in moles: (0.357 mol H2C2O4•2H2O / L) (.250 L ) = 0.0893 mol H2C2O4•2H2O

Amount in mass : 0.0893 mol H2C2O4•2H2O (126.08 g / mol ) = 11.2589 g H2C2O4•2H2O

Hope this answers the question. Have a nice day.