Giúp em vs mng oi 5⭐

$7,$

$a,$

`-` $Cu$ không phản ứng.

$n_{H_2}=0,25(mol)$

`-` Bảo toàn $e:$

$n_{Zn}=n_{H_2}=0,25(mol)$

`->`$\%m_{Zn}=\dfrac{0,25 \cdot 65}{20} \cdot 100\%=81,25\%$

`->`$\%m_{Cu}=100\%-81,25\%=18,75\%$

$b,$

`-` Bảo toàn nguyên tố $H:$

$n_{HCl}=2n_{H_2}=0,5(mol)$

$C_M=\dfrac{10dC\%}{M}=\dfrac{10 \cdot 1,2 \cdot 40}{36,5}=\dfrac{900}{73}(M)$

`=>`$V=\dfrac{0,5}{\dfrac{900}{73}}≈0,038(l)=38(ml)$

`a)`

`n_{H_2}={6,1975}/{24,79}=0,25(mol)`

`Zn+2HCl->ZnCl_2+H_2`

`0,25←0,5←0,25←0,25(mol)`

`->\%m_{Zn}={0,25.65}/{20}.100\%=81,25\%`

`->\%m_{Cu}=100-81,25=18,75\%`

`b)`

`m_{dd\ HCl}={0,5.36,5}/{40\%}=45,625(g)`

`->V_{dd\ HCl}={45,625}/{1,2}≈38,021(ml)`