What is the percent composition of copper 2 chloride?

Formula: CuO

Atomic weights:

Cu- 63.5 g

O- 16.0 g

Add together (molecular mass): 79.5 g

Take the weight of copper and divide it by the total molecular mass.

63.5 / 79.5 = 79.2% Cu

There is 79.2% of copper in copper II oxide