Show that the formula mass of CuBr₂ is 223.3u, and contains 28.4% Copper and 71.6% Bromine.

 

CuBr2

Cu or Copper has 63.546u while Br or Bromine has 79.904u. Now we to get the molar mass of the compound we have to add the atomic mass of its components.

*We multiply their atomic bass with how many atoms are there.

Cu = 63.546u (1) = 63.546u

Br2 = 79.904u (2) = 159.808u

CuBr2 = 63.546u + 159.808u = 223.354u

*We now obtain the percentage of the atom in the compound.

Cu% = (63.546u / 223.354u) (100) = 28.4% of Cu or Copper.

Br2% = (159.808u / 223.354u) (100) = 71.6% of Br2 or Bromine.