$a,PTPƯ:Zn+2HCl\xrightarrow{} ZnCl_2+H_2↑$
$b,n_{Zn}=\dfrac{13}{65}=0,2mol.$
$Theo$ $pt:$ $n_{ZnCl_2}=n_{Zn}=0,2mol.$
$⇒m_{ZnCl_2}=0,2.136=27,2g.$
$Theo$ $pt:$ $n_{H_2}=n_{Zn}=0,2mol.$
$c,PTPƯ:CuO+H_2\xrightarrow{t^o} Cu+H_2O$
$n_{CuO}=\dfrac{20}{80}=0,25mol.$
$\text{Lập tỉ lệ:}$ $\dfrac{0,25}{1}>\dfrac{0,2}{1}$
$⇒CuO$ $dư.$
$⇒n_{CuO}(dư)=0,2-\dfrac{0,2.1}{1}=0,05mol.$
$⇒m_{CuO}(dư)=0,05.80=4g.$
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