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.
Related compounds
Can't find the exact calculator you need?
Describe it in one sentence — get a working, math-verified calculator in seconds. Free, no signup.
Build your own calculatorRelated Calculators
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.