This problem is providing a chemical reaction between iron and oxygen to produce iron(III) oxide as follows:
[tex]4 Fe + 3 O_2 \rightarrow 2Fe_2O_3[/tex]
And asks for the produced mass of the oxide when 42.88 g of iron are consumed in excess oxygen. Thus, we can firstly write a calculation pathway from grams Fe to grams Fe₂O₃:
42.88 g Fe --> mol Fe --> mol Fe₂O₃ --> g Fe₂O₃
Which means we can set up the following dimensional analysis:
[tex]42.88gFe*\frac{1molFe}{55.85gFe} *\frac{2molFe_2O_3}{4molFe} *\frac{159.69gFe_2O_3}{1molFe_2O_3}\\\\= 61.30 gFe_2O_3[/tex]
This means you should no have multiplied by 6 but by 2/4 as the mole ratio of Fe to Fe₂O₃.
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