how many grams of Fe2O3 are formed when 16.7g of Fe reacts completely with oxygen?

2 answers

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Write and balance the equation.
4Fe + 3O2 ==> 2Fe2O3

Convert 16.7 g Fe to moles. moles = grams/molar mass

Using the coefficients in the balanced equation, convert moles Fe to moles Fe2O3.

Finally, convert moles Fe2O3 to grams. g = moles x molar mass.