The molar mass of nitrogen, N2, is 28.014 g/mol. That single number is what connects a mass you can weigh to an amount of substance you can react: one mole is 28.014 g, and a gram of it is 2.15e+22 formula units. The calculator turns any weighed mass into that count, and reports the amount in moles, millimoles and the mass of a single formula unit alongside it.
The figure comes from the formula. Nitrogen is 2 × 14.007 (N), which is 28.014 g/mol, taking standard atomic weights, and every page here computes that sum rather than quoting it. Nitrogen makes up the largest share of the mass: 2 of the 2 atoms in a formula unit are nitrogen, and they account for 28.014 g of the 28.014 g, or 100% by mass. The derivation table below breaks the whole molecule down element by element.
The numbers a bench actually uses sit at the millimole scale. One millimole of nitrogen is 28.014 mg and one micromole is 28.014 µg, so a balance reading to a milligram places you within 35.7 µmol. A single formula unit weighs 4.6518e-23 g, which is why the count in the gauge runs into the sextillions for any mass you can see.
Seventy-eight percent of the atmosphere and the reference gas for inerting. Also diatomic, so 28 g per mole rather than 14. At 28.014 g/mol it is heavier than 4 of the 11 gases and small molecules covered here, and that ranking matters more than it looks: carbon monoxide has a molar mass of 28.01 g/mol, so a gram of it contains 0.0143% more formula units than a gram of nitrogen. Weigh by mass and you are not weighing equal amounts of substance.
Because this is a gas, volume is often the easier measure. One mole of any ideal gas occupies 22.414 L at 0 °C and 1 atm and 24.4655 L at 25 °C, so 28.014 g of nitrogen — one mole — fills about 24.47 litres at room temperature. Real gases depart from that by a percent or so, more near their boiling point, but for ordinary work the molar volume is the quickest route from grams to litres.
The formula
m- The mass of nitrogen in grams
28.014- The molar mass of nitrogen in g/mol, derived from its formula
N- The number of formula units that mass contains
How it works, step by step
- Enter a mass of nitrogen in grams.
- It is divided by the molar mass, 28.014 g/mol, giving the amount in moles.
- That amount is multiplied by the Avogadro constant, 6.02214076 × 10²³ per mole, to give the number of formula units.
- The panel also reports the amount in moles and millimoles and the mass of one formula unit.
Worked examples
0.5 g of nitrogen as a molecule count
0.5 g divided by 28.014 g/mol is 0.0178482 mol, and multiplying by the Avogadro constant gives 1.075e+22 formula units of nitrogen. The same mass is 17.848 mmol, which is the figure a reaction is actually planned in.
5 g of nitrogen as a molecule count
5 g divided by 28.014 g/mol is 0.178482 mol, and multiplying by the Avogadro constant gives 1.075e+23 formula units of nitrogen. The same mass is 178.48 mmol, which is the figure a reaction is actually planned in.
50 g of nitrogen as a molecule count
50 g divided by 28.014 g/mol is 1.78482 mol, and multiplying by the Avogadro constant gives 1.075e+24 formula units of nitrogen. The same mass is 1784.8 mmol, which is the figure a reaction is actually planned in.
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Frequently asked questions
What is the molar mass of nitrogen (N2)?
It is 28.014 g/mol. That is the sum of the standard atomic weights of every atom in the formula: 2 × 14.007 (N). One mole of nitrogen therefore weighs 28.014 g, and a gram of it is 35.696 mmol.
What percentage of nitrogen is nitrogen?
100% by mass. Each formula unit contains 2 nitrogen atoms contributing 28.014 g of the 28.014 g total, so 100 g of nitrogen contains 100 g of nitrogen and a kilogram contains 1000 g of it.
How many molecules are in one gram of nitrogen?
About 2.15e+22. One gram is 0.0356964 mol, and each mole contains 6.02214076 × 10²³ formula units by definition of the mole, so the count is that constant divided by 28.014.
How much does a single molecule of nitrogen weigh?
4.6518e-23 g, which is 28.014 daltons. It is the molar mass divided by the Avogadro constant, and the number in daltons is numerically the same as the molar mass in g/mol — that equivalence is what makes the mole convenient.
Is molar mass the same as molecular weight?
They are the same number in ordinary use but not the same quantity. Molecular weight, properly relative molecular mass, is a ratio and has no unit: for nitrogen it is 28.014. Molar mass carries grams per mole: 28.014 g/mol. Because the mole is defined so those agree, you can read one off the other.
Why is the molar mass not a whole number?
Because standard atomic weights are averages over the isotopes found in nature. Nitrogen is quoted as 14.007 rather than a whole number for that reason, and the same applies to the other elements here, which is why nitrogen comes out at 28.014 g/mol rather than 28.
Molar mass, composition and mole equivalents of nitrogen
| Element | Atoms | Atomic weight | Contribution (g/mol) | By mass |
|---|---|---|---|---|
| Nitrogen (N) | 2 | 14.007 | 28.014 | 100% |
| Total — one mole of nitrogen | 28.014 | 100% |
Standard atomic weights, IUPAC 2021. The contribution column is atoms × atomic weight, and the total is the molar mass this page uses: 28.014 g/mol.
| Amount | Mass (g) | Mass (mg) | Formula units |
|---|---|---|---|
| 1 µmol | 0.000028 | 0.028014 | 6.022e+17 |
| 10 µmol | 0.00028014 | 0.28014 | 6.022e+18 |
| 100 µmol | 0.0028014 | 2.8014 | 6.022e+19 |
| 1 mmol | 0.028014 | 28.014 | 6.022e+20 |
| 10 mmol | 0.28014 | 280.14 | 6.022e+21 |
| 50 mmol | 1.4007 | 1400.7 | 3.011e+22 |
| 100 mmol | 2.8014 | 2801.4 | 6.022e+22 |
| 250 mmol | 7.0035 | 7003.5 | 1.506e+23 |
| 500 mmol | 14.007 | 14,007 | 3.011e+23 |
| 750 mmol | 21.0105 | 21,010.5 | 4.517e+23 |
| 1 mol | 28.014 | 28,014 | 6.022e+23 |
| 2 mol | 56.028 | 56,028 | 1.204e+24 |
| 5 mol | 140.07 | 140,070 | 3.011e+24 |
| 10 mol | 280.14 | 280,140 | 6.022e+24 |
Mass is the amount multiplied by 28.014 g/mol. The last column is that amount multiplied by the Avogadro constant, 6.02214076 × 10²³ per mole.
| Compound | Formula | Molar mass (g/mol) | Millimoles in 1 g |
|---|---|---|---|
| Ammonia | NH3 | 17.031 | 58.716 |
| Water | H2O | 18.015 | 55.509 |
| Carbon monoxide | CO | 28.01 | 35.702 |
| Nitrogen (this page) | N2 | 28.014 | 35.696 |
| Oxygen | O2 | 31.998 | 31.252 |
| Hydrogen peroxide | H2O2 | 34.014 | 29.4 |
| Carbon dioxide | CO2 | 44.009 | 22.723 |
Ordered by molar mass. The last column is 1000/M, which is the number a weighed gram actually gives you.