,nFe2(SO4)3=0.25*1=0.25mol=>nFe3+=0.5 mol
spư thu dc ran z ma ko tan trong H2SO4 loang=>ran Z la Cu,nCu dư=3.28/64=0.05125mol=>Fe tan het
va toan bo Fe(3+) chuyen len het Fe(2+) do Cu dư
dat nFe=x,nCu pư=y=>56x+64y+3.28=17.8 (1)
mat khac theo bt e
Fe=Fe(2+)+2e................Fe(3+)+1e=F...
x-------------> 2x 0.5---->0.5
Cu=Cu(2+)+2e
y------------->2y
vi ne cho=ne nhan=>2x+2y=0.5(2)=>x=0.185,y=0.065
mCu=3.28+0.065*64=7.44g