concentration calculation
 

If I am trying to make up a 5% w/v aqueous solution of sodium dithionite how many grams of power do I need and how many liters of water?

[The w/v] is the mass of the solute in grams multiplied by one hundred divided by the volume of solution in milliliters.

Does that help?

http://en.wikipedia.org/wiki/Concent...ume_percentage[/b]