a) \(m_{CuO}=\dfrac{25.16}{100}=4\left(g\right)\) => \(n_{CuO}=\dfrac{4}{80}=0,05\left(mol\right)\)
\(n_{Fe_2O_3}=\dfrac{16-4}{160}=0,075\left(mol\right)\)
PTHH: CuO + H2 --to--> Cu + H2O
0,05-->0,05--->0,05
Fe2O3 + 3H2 --to--> 2Fe + 3H2O
0,075-->0,225----->0,15
=> \(\left\{{}\begin{matrix}m_{Fe}=0,15.56=8,4\left(g\right)\\m_{Cu}=0,05.64=3,2\left(g\right)\end{matrix}\right.\)
b) \(n_{H_2}=0,05+0,225=0,275\left(mol\right)\)
=> \(V_{H_2}=0,275.22,4=6,16\left(l\right)\)