An experiment in your laboratory requires exactly 500mL of 0.0200M solution of Na2CO3. You are given solid Na2CO3, distilled water and a 500mL volumetric flask. describe how you would prepare the required solution.

Answer 1

You want how many moles? M x L = mols = 0.0200 x 0.500 = 0.01 mols.
Then grams = mols Na2CO3 x molar mass Na2CO3 = ?
Weigh out exactly that many grams Na2CO3, transfer quantitatively to a 500 mL volumetric flask, add some distilled water, swirl until all of the solid is dissolved, add more distilled water to the mark on the flask, stopper, mix thoroughly, label.