\(n_{O_2}=\dfrac{3,7185}{24,79}=0,15\left(mol\right)\\ 3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\\ n_{Fe}=\dfrac{3}{2}.n_{O_2}=1,5.0,15=0,225\left(mol\right)\\ \Rightarrow m_{Fe}=0,225.56=12,6\left(g\right)\\ n_{Fe_3O_4}=\dfrac{n_{O_2}}{2}=\dfrac{0,15}{2}=0,075\left(mol\right)\\ \Rightarrow m_{Fe_3O_4}=232.0,075=17,4\left(g\right)\)