\(m_{CO_2}=26.4\left(g\right)\Rightarrow n_{CO_2}=\dfrac{26.4}{44}=0.6\left(mol\right)\)
\(n_{O_2}=\dfrac{11.2}{22.4}=0.5\left(mol\right)\)
Bảo toàn nguyên tố O :
\(n_{H_2O}=0.1\cdot6+0.5\cdot2-0.6\cdot2=0.4\left(mol\right)\)
\(m=0.4\cdot18=7.2\left(g\right)\)