Consider the following reaction.

Question

Calculate the number of grams of  needed to react with 

Answer 1

Hi Ariel G.,

From the periodic table we see 1 mol C = 12.0 g C; 1 mol Fe = 55.845 g; 1 mol O = 15.9994 g.

Therefore 1 mol Fe₂O₃ = 2*55.845 + 3*15.9994 = 159.688g or 159.7 g Fe₂O₃ rounded.

And from the reaction equation 3 mols C = 2 mols Fe₂O₃.

? grams Fe₂O₃ = 20.0 g C*(1 mol C/12.0 g C)*(2 mols Fe₂O₃/3 mols C)*(159.7 g Fe₂O₃/1 mol Fe₂O₃) = 177.4 g Fe₂O₃ needed to react with C.

I hope this helps, Joe.