Molar MassMolar mass of sodium nitrite (NaNO2)
The molar mass of sodium nitrite, NaNO2, is 69.00 g/mol. One mole of it, which is 6.022 × 1023 formula units, has a mass of 69.00 grams.
About sodium nitrite
Sodium nitrite is used to cure meat and in making dyes by diazotisation. Do not confuse it with sodium nitrate, which has one more oxygen atom.
The working
The formula NaNO2 has 1 sodium atom, 1 nitrogen atom and 2 oxygen atoms, 4 atoms in all. Multiply each count by the atomic weight of the element and add:
| Element | Atoms | Atomic weight | Total | Share by mass |
|---|---|---|---|---|
| Sodium (Na) | 1 | 22.990 | 22.990 | 33.32% |
| Nitrogen (N) | 1 | 14.007 | 14.007 | 20.30% |
| Oxygen (O) | 2 | 15.999 | 31.998 | 46.38% |
22.990 + 14.007 + 2 × 15.999 = 68.995 g/mol
With the rounded atomic masses used in many school books (Na = 23, N = 14, O = 16) the answer is 69 g/mol. The difference from 69.00 is too small to matter in most school sums.
Percentage composition
By mass, NaNO2 is 33.32% sodium, 20.30% nitrogen and 46.38% oxygen. The largest share comes from oxygen. In a 100 g sample there are 33.3 g of sodium, 20.3 g of nitrogen and 46.4 g of oxygen.
Worked examples
Grams to moles. How many moles are in 25 g of NaNO2? Divide the mass by the molar mass: 25 ÷ 69.00 = 0.3623 mol.
Moles to grams. What is the mass of 0.1 mol of NaNO2? Multiply: 0.1 × 69.00 = 6.9 g.
Counting particles. 25 g contains 0.3623 mol × 6.022 × 1023 = 2.182 × 1023 formula units.
Making a solution. A 0.1 mol/L solution contains 0.1 × 69.00 = 6.9 g of NaNO2 in each litre. For 250 mL, weigh 1.725 g and make it up to the mark with water.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 6.9 g |
| 0.5 mol | 34.5 g |
| 1 mol | 69 g |
| 2 mol | 138 g |
| 5 mol | 345 g |
| Mass | Moles |
|---|---|
| 1 g | 0.01449 mol |
| 10 g | 0.1449 mol |
| 100 g | 1.449 mol |
| 1 kg | 14.49 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of NaNO2?
The molar mass of sodium nitrite (NaNO2) is 69.00 g/mol, or 68.995 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of NaNO2?
100 ÷ 69.00 = 1.449 mol.
What is the mass of one formula unit of NaNO2?
Divide the molar mass by the Avogadro constant: 69.00 ÷ 6.022 × 1023 = 1.146 × 10-22 g.
What is the percentage of oxygen in NaNO2?
Oxygen makes up 46.38% of the mass of NaNO2: 2 × 15.999 ÷ 68.995 × 100.
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.