Đáp án:
\(\begin{array}{l}
1,C\\
2,B\\
3,B\\
4,B\\
5,C\\
6,B\\
7,C
\end{array}\)
Giải thích các bước giải:
1,
\(\begin{array}{l}
Ba{(OH)_2} + S{O_2} \to BaS{O_3} + {H_2}O\\
Ba{(OH)_2} + C{O_2} \to BaC{O_3} + {H_2}O
\end{array}\)
2,
\(\begin{array}{l}
Fe + {H_2}S{O_4} \to FeS{O_4} + {H_2}\\
CaS{O_3} + {H_2}S{O_4} \to CaS{O_4} + S{O_2} + {H_2}O\\
ZnS + {H_2}S{O_4} \to ZnS{O_4} + {H_2}S\\
2KHC{O_3} + {H_2}S{O_4} \to {K_2}S{O_4} + 2C{O_2} + 2{H_2}O
\end{array}\)
3,
\(\begin{array}{l}
ZnO + 2HN{O_3} \to Zn{(N{O_3})_2} + {H_2}O\\
ZnO + 2KOH \to {K_2}Zn{O_2} + {H_2}O\\
A{l_2}{O_3} + 6HN{O_3} \to 2Al{(N{O_3})_3} + 3{H_2}O\\
A{l_2}{O_3} + 2KOH \to 2KAl{O_2} + {H_2}O
\end{array}\)
4,
\(\begin{array}{l}
Cu{(OH)_2} + 2HCl \to CuC{l_2} + 2{H_2}O\\
2Al + 6HCl \to 2AlC{l_3} + 3{H_2}\\
AgN{O_3} + HCl \to AgCl + HN{O_3}\\
CaS{O_3} + 2HCl \to CaC{l_2} + S{O_2} + {H_2}O
\end{array}\)
5,
\(\dfrac{{{m_{Ca}}}}{{{m_O}}} = \dfrac{{40}}{{16}} = 2,5\)
6,
\(\begin{array}{l}
2NaOH + C{O_2} \to N{a_2}C{O_3} + {H_2}O\\
2NaOH + S{O_2} \to N{a_2}S{O_3} + {H_2}O
\end{array}\)
7,
Gọi a và b là số mol của CuO và \(F{e_2}{O_3}\)
\(\begin{array}{l}
CuO + 2HCl \to CuC{l_2} + {H_2}O\\
F{e_2}{O_3} + 6HCl \to 2FeC{l_3} + 3{H_2}O\\
{n_{HCl}} = 0,7mol\\
\left\{ \begin{array}{l}
80a + 160b = 20\\
2a + 6b = 0,7
\end{array} \right.\\
\to a = 0,05 \to b = 0,1\\
\to \% {m_{CuO}} = \dfrac{{0,05 \times 80}}{{20}} \times 100\% = 20\% \\
\to \% {m_{F{e_2}{O_3}}} = 80\%
\end{array}\)
