How much carbon is needed to return 20 grams of copper (2) oxide? Calculate the amount of copper formed by the reaction

Dear student,
The reaction between Carbon and Copper oxide is :  CuO   +   C   $\stackrel{Heat }{\to }$  Cu  +  CO 
   Molar mass of CuO  =  63.5  +  16  = 79.5 g / mol
  Atomic mass of Carbon  =  12 g / mol
  79.5 g of CuO requires 12 g of C 
then, 20 g CuO requires $\frac{12\times 20}{79.5}$    =   3.02 g of C
Regards