[ClubRed]

I have a lab on Copper Chloride Dihyrdate, and the question says, "Use stoichiometry to calculate the theoretical yield of pure copper based on your initial mass of your sample." My sample of copper chloride dihyrdate was initially 1.03 g. The whole lab was about heating the compound to remove all the water and then to separate the Copper and Chlorine to form pure copper. Although, I have no idea how to find "theoretical yield" of copper. I really need some help, thanks so much.

[Arkcon]

Well, 1.03 g was the mass of the solid you started with.  If removed everything except copper, and lost none of the copper, what mass would you calculate would be left?  That would be the theoretical yield.  Which may not be exactly what you weigh afterward.