Assume that impure copper contains only iron, silver and a gold as impurities. After passage of `140A`, for `482.5` sec, of the mass of the anode decreased by `22.260g` and the cathode increased in mass by `22.011g`. Estimate the % iron and % copper originaly present.

Impure copper containing Fe, Au, 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 cathode by 22.011 g. Percentage of iron in impure copper is (Given molar mass Fe= 55.5 g "mol"^(-1) , molar mass Cu = 63.54 g "mol"^(-1) )

A sample of impure cuprous oxide contains 66.67% copper, by ,mass. What is the percentage of pure Cu_2 O in the sample? (Cu=63.5)