Đáp án:
D
Giải thích các bước giải:
Gọi số mol của Cu(NO3)2 và KNO3 lần lượt là a, b
\[\begin{array}{l}
2Cu{(N{O_3})_2}2CuO + 4N{O_2} + {O_2}\\
\,\,\,\,a\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2a\,\,\,\,\,\,\,\,\,\,\,\,\,0,5a\\
2KN{O_3}2KN{O_2} + {O_2}\\
\,\,\,b\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0,5b\\
{n_{N{O_2}}} = 2a\,\,;\,\,\,{n_{{O_2}}} = 0,5a + 0,5b\\
d = 18,8 \Rightarrow {\overline M _{(N{O_2},{O_2})}} = 18,8.2 = 37,6\\
\Leftrightarrow {\overline M _{(N{O_2},{O_2})}} = \frac{{{m_{N{O_2}}} + {m_{{O_2}}}}}{{{n_{N{O_2}}} + {n_{{O_2}}}}} = \frac{{2a.46 + 32.(0,5a + 0,5b)}}{{2a + 0,5a + 0,5b}} = 37,6\\
\Rightarrow 5a - b = 0\,\,\,\,(1)\\
{m_{Cu{{(N{O_3})}_2}}} + {m_{KN{O_3}}} = 34,65 \Rightarrow 188a + 101b = 34,65\,\,\,(2)
\end{array}\]
=> a=0,05; b=0,25 mol
\[{m_{Cu{{(N{O_3})}_2}}} = 0,05.188 = 9,4g\]
