At a pH of 4, the Cu-neocuproine complex formed in the liquid-liquid extraction experiment has a partition coefficient of about 6.5 when equilibrated between the acid aqueous solution and chloroform. Calculate the concentration of Cu in the chloroform phase if 39 mL of a 0.28 M aqueous Cu solution buffered to pH 4 is equilibrated with 12 mL of chloroform.