<h2>Energy is conserved. It never appears or disappears. It just changes from one kind of type to another. The Universe contains the same amount of energy it started with. This amount can never change.</h2><h2>
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n(2Fe2O3)=10g/319.374amu=0.03mol
n(4Fe+3O2)=0.03 mol
m(4Fe+2O2)=Mn=319.374×0.03=9.58=10