Gọi số mol các muối lần lượt là a, b (mol)
PTHH: \(2KNO_3\underrightarrow{t^o}2KNO_2+O_2\)
_________a--------------------->0,5a______(mol)
\(4Fe\left(NO_3\right)_2\underrightarrow{t^o}2Fe_2O_3+8NO_2+O_2\)
____b-------------------------->2b---->0,25b______(mol)
=> \(\left\{{}\begin{matrix}n_{O_2}=0,5a+0,25b\left(mol\right)\\n_{NO_2}=2b\left(mol\right)\end{matrix}\right.=>\left\{{}\begin{matrix}m_{O_2}=\left(0,5a+0,25b\right).32=16a+8b\left(g\right)\\m_{NO_2}=2b.46=92b\left(g\right)\end{matrix}\right.\)
=> \(M_{hh}=\frac{16a+8b+92b}{0,5a+0,25b+2b}=\frac{232}{11}.2\)
Mà \(n_{hh}=\frac{12,32}{22,4}=0,55=>0,5a+0,25b+2b=0,55\)
=> \(\left\{{}\begin{matrix}a=0,2\left(mol\right)\\b=0,2\left(mol\right)\end{matrix}\right.\)
=> \(m=0,2.101+0,2.180=56,2\left(g\right)\)
