A hematite sample holds 34.97 g of iron. Using Fe = 55.85 g/mol, how many moles of iron is this?

1. Deriving a formula from masses starts by converting each element mass into moles. 2. Divide the iron mass by the molar mass of iron: 34.97 g / 55.85 g/mol. 3. The result is 0.6261 mol of iron. 4. The value 0.9394 mol is the oxygen amount in the same sample, not the iron amount. 5. The value 1.597 mol comes from dividing the molar mass by the mass, which inverts the ratio. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.2 Determining Empirical and Molecular Formulas_