% of chlorine in CuCI2

Answer 1

Cu atomic mass = 63.55 g/mole

Cl atomic mass = 35.45 g/mole x 2 Cl = 70.9 g of Cl

Total mass of CuCl2 = 63.55 g + 70.9 g = 134.45 g

% Cl = 70.9 g/134.45 g (x100%) = 52.7% by mass