100% ........................ 142,23g Cu impur
90% ........................ m.pura = 128 g Cu pur
128g V L n moli
2Cu + O2 --> 2CuO
2x64 22,4 2x80
=> V = 128x22,4/2x64 = 22,4 L O2
=> n = 128x2x80/2x64 = 160 g CuO
n = nr.moli = m/M, M.CuO = 80 g/mol
=> n = 160/80 = 2 moli CuO