Just find the molecular weight of Citric acid (anhydrous, of
course).  Multiply that by the molar amount (5 mol/L)and the total volume
(200 mL in your case).  That should tell you the amount of solid Citric
Acid you need to add to your solution.  Make sure you do not add the solid
to all 200mL of water because your end volume would be higher.  Start with
approximately 150 mL of water, add the acid, and then see what volume you
have.  If you have less that 200 mL you will have to add more water.  Hope
this helps.  The formula is,

mass = (desired mol/L)*(total volume, L)*(molecular weight, g/mol)


At 12:55 PM 2/21/2005, you wrote:
>Can anyone tell me how to make a 5M citric acid solution?  If I use 200 ml
>of DI water as the solvent, let's say, how many grams of the anhydrous
>citric acid solid do I need to make 5M?  And what is the formula to figure
>this out?