Cu+2H2SO4=CuSO4+SO2+2H2O
c=md/msx100
md=cxms/100=80x183,75/100=147 g H2SO4 participa la reactie
M H2SO4=2+32+4x16=98 g/mol
64 gCu..................2x98g H2SO4
X gCu..................147 gH2SO4
X=147x64/2x98=48 gCu consumat
4/100x48=1,92 gimpuritati
48-1,92=46.08 g Cu pur