# How can I find the percent compositions of CuBr2?

Just to retire this question....I make it approx. 28% metal content by mass....
The molar mass of cupric bromide is $223.37 \cdot g \cdot m o {l}^{-} 1$...
And thus %Cu=(63.55*g*mol^-1)/(223.37*g*mol^-1)xx100%=??%
And so what is %Br?