Copper containing Fe, Au, and Ag as impurities is electrolytically refined. A current of 140 A for 482.5 s decreased the mass of the anode by 22.26 g and increased the mass of the cathode by 22.011 g. The percentage of iron in the impure copper is (Given molar mass Fe = 55.5 g/mol, molar mass Cu = 63.54 g/mol).