Bài 23:
PTHH: \(Zn+CuSO_4\rightarrow ZnSO_4+Cu\)
Gọi \(n_{Zn\left(p.ứ\right)}=a\left(mol\right)=n_{Cu}=n_{CuSO_4}\)
Tăng giảm khối lượng: \(m_{Zn\left(sau\right)}=m_{Zn\left(ban.đầu\right)}-m_{Zn\left(p.ứ\right)}+m_{Cu}\)
\(\Rightarrow24,96=25-65a+64a\) \(\Leftrightarrow a=0,04\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}m_{Zn\left(p.ứ\right)}=0,04\cdot65=2,6\left(g\right)\\m_{CuSO_4}=0,04\cdot160=6,4\left(g\right)\\\end{matrix}\right.\)
Bài 24:
PTHH: \(2Al+3CuSO_4\rightarrow Al_2\left(SO_4\right)_3+3Cu\)
Gọi \(n_{Al\left(p.ứ\right)}=2a\left(mol\right)\) \(\Rightarrow n_{Cu}=3a\left(mol\right)\)
Tăng giảm khối lượng: \(m_{giảm}=m_{Cu}-m_{Al\left(p.ứ\right)}\)
\(\Rightarrow64\cdot3a-27\cdot2a=1,38\) \(\Leftrightarrow a=0,01\) \(\Rightarrow m_{Al}=0,01\cdot2\cdot27=0,54\left(g\right)\)
