Molar Mass of Fe₂O₃
Iron(III) oxide (rust, hematite). Iron is +3 here: two Fe³⁺ ions balance three O²⁻ ions.
Molar mass of Fe2O3
159.687 g/mol
2 × 55.845 + 3 × 15.999 = 159.687
Calculation, element by element
| Element | Atoms | Atomic mass (g/mol) | Subtotal | Mass % |
|---|---|---|---|---|
| Iron (Fe) | 2 | 55.845 | 111.690 | 69.94% |
| Oxygen (O) | 3 | 15.999 | 47.997 | 30.06% |
| Total | 159.687 | 100% |
= 0.062623 mol = 3.7712 × 1022 formula units
Fe₂O₃ molar mass FAQ
What is the molar mass of iron(iii) oxide (Fe₂O₃)?
159.687 g/mol. It is the sum of the atomic masses of every atom in the formula: 2 × 55.845 + 3 × 15.999 = 159.687 g/mol.
How many grams are in one mole of Fe₂O₃?
159.687 g. Molar mass is the mass of one mole (6.022 × 10²³ formula units), so 1 mol of Fe₂O₃ weighs 159.687 g and 0.5 mol weighs 79.844 g.
How many moles are in 10 g of Fe₂O₃?
10 g ÷ 159.687 g/mol = 0.06262 mol.
What is the percent composition of Fe₂O₃?
Iron 69.94%, Oxygen 30.06%.
Is molecular weight the same as molar mass for Fe₂O₃?
Numerically yes: the molecular (or formula) weight is 159.687 u per formula unit, and the molar mass is 159.687 g/mol.
Molar masses of other common compounds
H2O WaterNaCl Sodium chlorideNaOH Sodium hydroxideC6H12O6 GlucoseCO2 Carbon dioxideHCl Hydrochloric acidH2SO4 Sulfuric acidO2 Oxygen gasCaCO3 Calcium carbonateC2H5OH EthanolNH3 AmmoniaN2 Nitrogen gasCH4 MethaneCuSO4 Copper(II) sulfateKMnO4 Potassium permanganateMgCl2 Magnesium chlorideCuSO4·5H2O Copper(II) sulfate pentahydrateNaHCO3 Sodium bicarbonateNa2CO3 Sodium carbonateKCl Potassium chlorideHNO3 Nitric acidH3PO4 Phosphoric acidCH3COOH Acetic acidC12H22O11 SucroseH2O2 Hydrogen peroxideCa(OH)2 Calcium hydroxideAl2O3 Aluminium oxideAgNO3 Silver nitrateNH4NO3 Ammonium nitrateC8H10N4O2 CaffeineC9H8O4 AspirinC3H8 PropaneC8H18 OctaneH2 Hydrogen gasCl2 Chlorine gasO3 OzoneCO Carbon monoxideSO2 Sulfur dioxideKOH Potassium hydroxideMgO Magnesium oxideCaCl2 Calcium chlorideNaNO3 Sodium nitrateK2Cr2O7 Potassium dichromateBaSO4 Barium sulfate