Em tham khảo nha :
\(\begin{array}{l}
3)\\
a)\\
Zn + 2HCl \to ZnC{l_2} + {H_2}\\
b)\\
{n_{Zn}} = \dfrac{m}{M} = \dfrac{{13}}{{65}} = 0,2mol\\
{n_{{H_2}}} = {n_{Zn}} = 0,2mol\\
{V_{{H_2}}} = 0,2 \times 22,4 = 4,48l\\
c)\\
{n_{HCl}} = \dfrac{m}{M} = \dfrac{{3,65}}{{36,5}} = 0,1mol\\
\dfrac{{0,2}}{1} > \dfrac{{0,1}}{2} \Rightarrow Zn\text{ dư}\\
{n_{{H_2}}} = \dfrac{{{n_{HCl}}}}{2} = 0,05mol\\
{V_{{H_2}}} = 0,05 \times 22,4 = 1,12l\\
4)\\
a)\\
2{H_2} + {O_2} \to 2{H_2}O\\
b)\\
{n_{{H_2}}} = \dfrac{V}{{22,4}} = \dfrac{{2,24}}{{22,4}} = 0,1mol\\
{n_{{H_2}O}} = {n_{{H_2}}} = 0,1mol\\
{m_{{H_2}O}} = 0,1 \times 18 = 1,8g\\
c)\\
{n_{{O_2}}} = \dfrac{V}{{22,4}} = \dfrac{{2,24}}{{22,4}} = 0,1mol\\
\dfrac{{0,1}}{2} < \dfrac{{0,1}}{1} \Rightarrow {O_2}\text{ dư}\\
{n_{{H_2}O}} = {n_{{H_2}}} = 0,1mol\\
{m_{{H_2}O}} = 0,1 \times 18 = 1,8g
\end{array}\)
