Including water in molar mass for molarity?

[mishima]

Hi, let's say I need 60 mL of a 1M solution of potassium sodium tartrate, I am looking for how many grams to measure out of my stock. So I need to convert mol to grams using molar mass. Do I use the full formula weight that includes water KNaC₄H₄O₆*4H₂O, or simply the KNaC₄H₄O₆?

 

[mfb]

You need a specific number of molecules of your substance. If every molecule carries 4 H₂O around, you have to take more mass to get the same number of molecules.
Use the full formula weight, including H₂O.

 

[mishima]

Thanks for that clarification.