How many grams of iron must be oxidized to produce 5.0g of rust? (Fe2O3)

Question

I have no idea how to solve this!

Answer 1

If your reaction is

4Fe + 3O2 -> 2Fe2O3

then it takes 2 moles of Fe to produce 1 mole of rust.

5.0g of rust is 0.0313 moles

So, how many grams of Fe in 0.626 moles?

Answer 2

would it be 10? since it takes double the amount of Fe to make rust. 5.0g of rust is .0313 moles, you would multiply it by 2?

Answer 3

1. Steve moved the decimal point; that should be 0.0626 mols.
2. John, that answer is not right.
g = mols x molar mass = 0.0626 x 55.85 = ?