1. Assume a 100-gram Sample

This makes the calculations easier. In a 100-gram sample:

* Iron (Fe): 65.0 grams

* Oxygen (O): 35.0 grams

2. Convert Grams to Moles

* Moles of Fe = (65.0 g Fe) / (55.845 g/mol Fe) = 1.164 mol Fe

* Moles of O = (35.0 g O) / (15.9994 g/mol O) = 2.188 mol O

3. Find the Simplest Mole Ratio

Divide each mole value by the smallest mole value (1.164 mol Fe):

* Fe: 1.164 mol / 1.164 mol = 1

* O: 2.188 mol / 1.164 mol = 1.88 ≈ 2 (round to the nearest whole number)

4. Write the Empirical Formula

The empirical formula represents the simplest whole-number ratio of atoms in a compound. Therefore, the empirical formula of this iron oxide is FeO₂.