Going from grams to moles for sodium nitrite means dividing by its molar mass, 68.994769 g/mol. One gram is 0.0144939 mol, or 14.4939 mmol; 100 mg is 1.4494 mmol; and a 68.99477 g portion is exactly one mole. The division is the whole calculation, but the molar mass has to be the one for the exact formula you have, NaNO2, which is where these figures come from.
The figure comes from the formula. Sodium nitrite is 22.9898 (Na) + 14.007 (N) + 2 × 15.999 (O), which is 68.994769 g/mol, taking standard atomic weights, and every page here computes that sum rather than quoting it. Oxygen makes up the largest share of the mass: 2 of the 4 atoms in a formula unit are oxygen, and they account for 31.998 g of the 68.99477 g, or 46.38% by mass. The derivation table below breaks the whole molecule down element by element.
Balance resolution is the practical limit here. On a two-decimal balance the smallest step is 10 mg, which is 0.1449 mmol of sodium nitrite; on a three-decimal balance it is 1 mg, or 14.49 µmol. To hit a target within 1% you therefore need to weigh at least a gram on the first and at least 100 mg on the second, and below that a stock solution measured by pipette beats weighing.
The curing salt in bacon and ham, used at a fraction of a percent, and a corrosion inhibitor. Pink curing salt is 6.25% of it in sodium chloride. At 68.99477 g/mol it is heavier than 2 of the 34 salts covered here, and that ranking matters more than it looks: sodium chloride has a molar mass of 58.43977 g/mol, so a gram of it contains 18.1% more formula units than a gram of sodium nitrite. Weigh by mass and you are not weighing equal amounts of substance.
Purity is the usual gap between the calculation and the balance. A reagent sold at 98% means 1.3799 g of a nominal 68.99477 g is something else, so for exact work you divide the weighed mass by the assay figure on the certificate. For most purposes the difference is smaller than the error in reading the meniscus, but it is systematic rather than random, so it does not average out.
The formula
m- The mass you weighed, in grams
68.994769- The molar mass of sodium nitrite in g/mol, derived from its formula
n- The amount of substance in moles
How it works, step by step
- Enter the mass you weighed, in grams.
- It is divided by 68.994769 g/mol, the molar mass of sodium nitrite.
- The result is the amount of substance in moles, with millimoles and micromoles beneath it.
- Check it against the table if you want the figure for a standard weighing rather than a typed mass.
Worked examples
0.25 g of sodium nitrite in moles
0.25 ÷ 68.99477 = 0.00362346 mol, or 3.6235 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 14.49 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
2 g of sodium nitrite in moles
2 ÷ 68.99477 = 0.0289877 mol, or 28.988 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 14.49 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
25 g of sodium nitrite in moles
25 ÷ 68.99477 = 0.362346 mol, or 362.35 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 14.49 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
How to read your score
Frequently asked questions
What is the molar mass of sodium nitrite (NaNO2)?
It is 68.994769 g/mol. That is the sum of the standard atomic weights of every atom in the formula: 22.9898 (Na) + 14.007 (N) + 2 × 15.999 (O). One mole of sodium nitrite therefore weighs 68.99477 g, and a gram of it is 14.494 mmol.
What percentage of sodium nitrite is oxygen?
46.38% by mass. Each formula unit contains 2 oxygen atoms contributing 31.998 g of the 68.99477 g total, so 100 g of sodium nitrite contains 46.38 g of oxygen and a kilogram contains 463.77 g of it.
How do I convert grams of sodium nitrite to moles?
Divide the mass in grams by 68.994769 g/mol. So 1 g is 0.0144939 mol, 10 g is 0.144939 mol and 100 g is 1.44939 mol. Nothing else enters the calculation — no volume, no temperature, no concentration.
How many moles is 100 g of sodium nitrite?
1.44939 mol, which is 1449.39 mmol. Read the other way, one mole of sodium nitrite is 68.99477 g, so 100 g is 1.449 of a mole.
What about milligrams and micromoles?
The same division, scaled. A milligram of sodium nitrite is 14.494 µmol, 10 mg is 144.94 µmol and 100 mg is 1.4494 mmol. Working in µmol per mg avoids the string of leading zeros that mol per g produces at this scale.
Does purity change the number of moles?
Yes, in proportion. A 98% pure sample weighing 1 g contains 0.98 g of sodium nitrite, which is 0.014204 mol rather than 0.0144939 mol. The calculator assumes the mass you enter is the compound itself, so divide by the assay figure first if you need the corrected amount.
Grams to moles reference for sodium nitrite
| Element | Atoms | Atomic weight | Contribution (g/mol) | By mass |
|---|---|---|---|---|
| Oxygen (O) | 2 | 15.999 | 31.998 | 46.38% |
| Sodium (Na) | 1 | 22.98977 | 22.98977 | 33.32% |
| Nitrogen (N) | 1 | 14.007 | 14.007 | 20.3% |
| Total — one mole of sodium nitrite | 68.994769 | 100% |
Standard atomic weights, IUPAC 2021. The contribution column is atoms × atomic weight, and the total is the molar mass this page uses: 68.994769 g/mol.
| On the balance | Moles | Millimoles | Micromoles |
|---|---|---|---|
| 1 mg | 0.000014 | 0.0144939 | 14.4939 |
| 5 mg | 0.000072 | 0.0724693 | 72.4693 |
| 10 mg | 0.000144939 | 0.144939 | 144.939 |
| 25 mg | 0.000362346 | 0.362346 | 362.346 |
| 50 mg | 0.000724693 | 0.724693 | 724.693 |
| 100 mg | 0.00144939 | 1.44939 | 1449.39 |
| 250 mg | 0.00362346 | 3.62346 | 3623.46 |
| 500 mg | 0.00724693 | 7.24693 | 7246.93 |
| 1 g | 0.0144939 | 14.4939 | 14,493.9 |
| 2 g | 0.0289877 | 28.9877 | 28,987.7 |
| 5 g | 0.0724693 | 72.4693 | 72,469.3 |
| 10 g | 0.144939 | 144.939 | 144,939 |
| 25 g | 0.362346 | 362.346 | 362,346 |
| 50 g | 0.724693 | 724.693 | 724,693 |
| 100 g | 1.44939 | 1449.39 | 1449385.236643 |
| 250 g | 3.62346 | 3623.46 | 3623463.091607 |
| 500 g | 7.24693 | 7246.93 | 7246926.183213 |
Every row is the mass divided by 68.994769 g/mol. A balance reading to 1 mg resolves 14.49 µmol of this compound, which is the smallest step the middle columns can really move in.
| Compound | Formula | Molar mass (g/mol) | Millimoles in 1 g |
|---|---|---|---|
| Ammonium chloride | NH4Cl | 53.489 | 18.695 |
| Sodium chloride | NaCl | 58.43977 | 17.112 |
| Sodium nitrite (this page) | NaNO2 | 68.99477 | 14.494 |
| Sodium hypochlorite | NaClO | 74.43877 | 13.434 |
| Potassium chloride | KCl | 74.5483 | 13.414 |
| Ammonium nitrate | NH4NO3 | 80.043 | 12.493 |
| Sodium bicarbonate | NaHCO3 | 84.00577 | 11.904 |
Ordered by molar mass. The last column is 1000/M, which is the number a weighed gram actually gives you.