Câu 1.
a) \(Zn+2HCl\rightarrow ZnCl_2+H_2\) (1)
\(ZnO+2HCl\rightarrow ZnCl_2+H_2O\) (2)
b) \(n_{H_2}=n_{Zn}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
\(\Rightarrow\%m_{Zn}=\dfrac{0,15.65}{21,9}.100=44,52\%\)
\(\Rightarrow\%ZnO=100-44,52=55,48\%\)
c)\(n_{HCl\left(bđ\right)}=0,8.0,5=0,4\left(mol\right)\)
\(n_{HCl\left(2\right)}=n_{HCl\left(bđ\right)}-n_{HCl\left(1\right)}=0,4-0,15.2=0,1\left(mol\right)\)
\(n_{ZnCl_2\left(1\right)}=n_{H_2}=0,15\left(mol\right)\)
\(n_{ZnCl_2\left(2\right)}=\dfrac{1}{2}n_{HCl\left(2\right)}=0,05\left(mol\right)\)
\(C_{M\left(ZnCl_2\right)}=\dfrac{0,15+0,05}{0,8}=0,25M\)
2. CuO không tan trong nước nên không tính được nồng độ dung dịch thu được em nhé!
3. \(Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\)
\(n_{Na}=\dfrac{6,9}{23}=0,3\left(mol\right)\)
\(n_{H_2}=\dfrac{1}{2}n_{Na}=0,15\left(mol\right)\)
\(V_{H_2}=0,15.22,4=3,36\left(mol\right)\)
b) \(C\%_{NaOH}=\dfrac{0,3.40}{6,9+120-0,15.2}.100=9,48\%\)
