What concn do you want the stock solution?
mols you want = M x L = ?
Then 0.40M x mL = 750 x concn.
Note: The above is the correct solution to the problem posted; however, I suspect what you meant was how to prepare 750 mL of a stock solution OF (not with) 0.40M Na2S2O3.
How to prepare a 750mL stock solution with a 0.40 M Na2S2O3.
3 answers
Yes, I should have typed of, how would I go into more detail of the procedure to make this stock solution? In other words, calculating the of each chemical needed, how much sodium and thiosulfate would need to be added. Thanks again, DrBob222.
You want to prepare 750 mL of a 0.4M Na2S2O3 solution.
You want how many mols? That's M x L = 0.40 M x 0.750 L = 0.30 mols.
mols Na2S2O3 = grams Na2S2O3/molar mass
g = mols x molar mass = 0.3 x molar mass Na2S2O3.
Weigh out that many grams Na2S2O3, place into a 750 mL volumetric flask, add distilled water, swirl until all of the solute is dissolved, make to the mark with distilled water.
You want how many mols? That's M x L = 0.40 M x 0.750 L = 0.30 mols.
mols Na2S2O3 = grams Na2S2O3/molar mass
g = mols x molar mass = 0.3 x molar mass Na2S2O3.
Weigh out that many grams Na2S2O3, place into a 750 mL volumetric flask, add distilled water, swirl until all of the solute is dissolved, make to the mark with distilled water.
2 answers