chemistry
posted by Justin .
copper (II) flourine comtains 37.42 % of mass. use this percentage to calculate the mass of flourine in grams contained in 28.5 g of copper (II) flourine

You have a bushel of apples and other fruits; the percent apples = 25%. How many apples do you have if the total number of items = 108. Obviously you will do 108 x 0.25 = 27 apples. That's no different with atoms.
%F in CuF is 37.42%.
So mass F in 28.5g CuF2 is 28.5 x 0.3742 = 
af