Molar Mass of Iron(II) oxide
FeO — 71.844 g/mol, worked out element by element.
Molar mass of Iron(II) oxide, FeO
71.844 g/mol
Molecular weight 71.844 · 2 atoms per formula unit
Also known as: feo, ferrous oxide.
The other common iron oxide — same elements, different ratio, different name.
How 71.844 g/mol is worked out
| Element | Atoms | Atomic mass | Mass | % of total |
|---|---|---|---|---|
| Iron | 1 | 55.845 | 55.845 | 77.73% |
| Oxygen | 1 | 15.999 | 15.999 | 22.27% |
| Total | 2 | 71.844 | 100% |
M = 1 × 55.845 + 1 × 15.999 = 71.844 g/mol
Grams to moles for Iron(II) oxide
| Mass | Moles | Formula units |
|---|---|---|
| 1 g | 0.0139 mol | 8.382 × 10^21 |
| 10 g | 0.1392 mol | 8.382 × 10^22 |
| 25 g | 0.3480 mol | 2.096 × 10^23 |
| 50 g | 0.6960 mol | 4.191 × 10^23 |
| 100 g | 1.3919 mol | 8.382 × 10^23 |
| 250 g | 3.4798 mol | 2.096 × 10^24 |
| 71.844 g | 1 mol | 6.022 × 10^23 |
For any other amount, use the molar mass calculator, or the molarity calculator to make up a solution of a given concentration.
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Frequently Asked Questions
What is the molar mass of Iron(II) oxide?
The molar mass of Iron(II) oxide (FeO) is 71.844 g/mol. That is the sum of the standard atomic weights of all 2 atoms in one formula unit: 1 × 55.845 + 1 × 15.999 = 71.844.
What is the molecular weight of Iron(II) oxide?
71.844 — the same number as the molar mass, but as a dimensionless ratio rather than in g/mol. The two terms describe the same arithmetic, so a molecular weight of 71.84 and a molar mass of 71.84 g/mol are the same answer.
How many moles are in 100 g of Iron(II) oxide?
100 ÷ 71.844 = 1.3919 mol. To convert any mass to moles, divide by the molar mass; to go the other way, multiply.
What is the percent composition of Iron(II) oxide?
By mass, Iron(II) oxide is 77.73% iron, 22.27% oxygen. Each element's share is its total mass in the formula divided by 71.844.
How many atoms are in one formula unit of Iron(II) oxide?
2: 1 iron, 1 oxygen. One mole contains 6.02214076 × 10²³ formula units, so a mole of Iron(II) oxide contains 2 × 6.022 × 10²³ atoms in total.