Câu 2. Sgk
Câu 3.
a) `2Al+6HCl->2AlCl_3+3H_2`
`Fe+2HCl->FeCl_2+H_2`
Chất rắn không tan là Cu.
`%m_(Cu)=(2)/(10,3).100=19,42%`
`n_(Al)=a;n_(Fe)=b`
`=>27a+56b=8,3`
`n_(H_2)=(5,6)/(22,4)=0,25(mol)`
`=>3/2 a+b=0,25`
`=>a=0,1;b=0,1`
`=>%m_(Al)=(27.0,1)/(10,3)=26,21%`
`%m_(Fe)=100-26,21-19,42=54,37%`
b) `n_(HCl)=2n_(H_2)=0,5(mol)`
Btkl:
`m_(m uối)=m_(KL)+m_(HCl)-m_(H_2)`
`=>m_(m uối)=8,3+0,5.36,5-0,25.2=26,05(g)`