Question

Pure iron (Fe) reacts with oxygen gas (02) to produce iron(III) oxide (Fe203)How many grams of O2 must be used to fully react with 25.0 grams of Fe?

Answer 1

First, we write down the reaction

4 Fe + 3 O2 => 2 Fe2O3 (Don't forget to balance it)

We also need the molar masses:

For O2) 32.0 g/mol

For Fe) 55.8 g/mol

Procedure: We use stoichiometry

3 x 32 g of O2 (1 mole) -------------- 4 x 55.8 g of Fe (1 mole)

X -------------- 25.0 g of Fe

X = 10.8 g of O2 are needed

Answer: 10.8 g of O2