I’ve made magnetite $\ce{Fe3O4}$ in the lab and now I need to calculate yield percentage. How can I do it? I have these data.
\begin{align} \ce{FeSO4.7H2O(aq) &-> Fe^2+(aq) + SO4^2- (aq) + 7H2O(l)}\\ \ce{KOH(aq) &-> K+(aq) + OH- (aq)}\\ \ce{KNO3(aq) &-> K+(aq) + NO3- (aq)}\\ \ce{Fe^2+(aq) + 2OH- (aq) &-> Fe(OH)2(s)}\\ \ce{3Fe(OH)2(s) + NO3- (aq) &-> Fe3O4(s) + NO2- (aq) + 3H2O(l)}\\ \end{align}
\begin{align} \ce{FeSO4.7H2O &->} 4.20~\mathrm{g}\\ \ce{KOH &->} 1.90~\mathrm{g}\\ \ce{KNO3 &->} 0.12~\mathrm{g}\\ \text{Magnetite}~\ce{&->} 0.36~\mathrm{g}\\ \end{align}
I know how to calculate the yield for simple reactions but I don’t know how to do it when there are many reactions involved.