Molar MassMolar mass of nitrogen (N2)
The molar mass of nitrogen, N2, is 28.01 g/mol. One mole of it, which is 6.022 × 1023 molecules, has a mass of 28.01 grams.
28.01 g/mol
2 × 14.007 = 28.014 · 2 atoms in the formula · also called dinitrogen
About nitrogen
Nitrogen makes up about 78 percent of air by volume. The gas is made of very stable two-atom molecules.
Other names: dinitrogen.
The working
The formula N2 has 2 nitrogen atoms. Multiply each count by the atomic weight of the element and add:
| Element | Atoms | Atomic weight | Total | Share by mass |
|---|---|---|---|---|
| Nitrogen (N) | 2 | 14.007 | 28.014 | 100.00% |
2 × 14.007 = 28.014 g/mol
With the rounded atomic masses used in many school books (N = 14) the answer is 28 g/mol. The difference from 28.01 is too small to matter in most school sums.
Percentage composition
N2 contains only nitrogen, so nitrogen makes up 100% of its mass. Each molecule has 2 atoms, which is why the molar mass is 2 times the atomic weight 14.007.
Worked examples
Grams to moles. How many moles are in 10 g of N2? Divide the mass by the molar mass: 10 ÷ 28.01 = 0.357 mol.
Moles to grams. What is the mass of 1.5 mol of N2? Multiply: 1.5 × 28.01 = 42.02 g.
Counting particles. 10 g contains 0.357 mol × 6.022 × 1023 = 2.150 × 1023 molecules, and 4.299 × 1023 atoms in all.
As a gas. At 0 °C and 1 atmosphere one mole of an ideal gas occupies 22.4 litres, so the density of N2 is about 28.01 ÷ 22.4 = 1.25 g per litre. Air averages about 29 g/mol, so this gas is lighter than air.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 2.801 g |
| 0.5 mol | 14.01 g |
| 1 mol | 28.01 g |
| 2 mol | 56.03 g |
| 5 mol | 140.1 g |
| Mass | Moles |
|---|---|
| 1 g | 0.0357 mol |
| 10 g | 0.357 mol |
| 100 g | 3.57 mol |
| 1 kg | 35.7 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of N2?
The molar mass of nitrogen (N2) is 28.01 g/mol, or 28.014 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of N2?
100 ÷ 28.01 = 3.57 mol.
What is the mass of one molecule of N2?
Divide the molar mass by the Avogadro constant: 28.01 ÷ 6.022 × 1023 = 4.652 × 10-23 g.
Which values? This site uses the abridged standard atomic weights published by IUPAC (CIAAW), read on 12 November 2026. Your textbook or question paper may round them differently, for example H = 1 and O = 16, so its answer can differ slightly. In an exam, use the values the paper gives.