Calculate the mass percent of copper in cus, copper(ii) sulfide. if you wish to obtain 10.0g of copper metal from copper(ii) sulfide, what mass of cus (in grams) must you use?

Using the relative atomic weights of both copper and sulfur ie copper = 63.55 and sulfur is 32.06 so 63.55+32.06=95.56 total mass and so of this, copper = 63.55/95.56=66.4%. So to get 10 grams of copper, use the formula 10g=66.4%xCuS so CuS=10/0.664=15.06 grams of CuS. 

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