Em tham khảo nha:
\(\begin{array}{l}
7)\\
4Fe{S_2} + 11{O_2} \xrightarrow{t^0} 2F{e_2}{O_3} + 8S{O_2}\\
2S{O_2} + {O_2} \xrightarrow{t^0,V_2O_5} 2S{O_3}\\
S{O_3} + {H_2}O \to {H_2}S{O_4}\\
S{O_2} + NaOH \to NaHS{O_3}\\
NaHS{O_3} + NaOH \to N{a_2}S{O_3} + {H_2}O\\
8)\\
a)\\
CaC{O_3} + 2HCl \to CaC{l_2} + C{O_2} + {H_2}O\\
{n_{C{O_2}}} = \dfrac{{0,448}}{{22,4}} = 0,02\,mol\\
{n_{CaC{O_3}}} = {n_{C{O_2}}} = 0,02\,mol\\
{m_{CaC{O_3}}} = 0,02 \times 100 = 2g\\
{m_{CaS{O_4}}} = 5 - 2 = 3g\\
b)\\
{n_{HCl}} = 2{n_{C{O_2}}} = 0,04\,mol\\
a = {C_M}HCl = \dfrac{{0,04}}{{0,25}} = 0,16M
\end{array}\)
