Molarity is moles of solute per litre of solution, so for sodium bicarbonate it is the mass divided by 84.005769 g/mol and then by the volume in litres. One gram in 100 mL is 0.11904 mol/L; the same gram in a litre is 0.011904 mol/L; and 84.00577 g in a litre is a 1 M solution. Enter a mass and a volume and the calculator does both divisions, and also reports the strength as g/L and % w/v.
The figure comes from the formula. Sodium bicarbonate is 22.9898 (Na) + 1.008 (H) + 12.011 (C) + 3 × 15.999 (O), which is 84.005769 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: 3 of the 6 atoms in a formula unit are oxygen, and they account for 47.997 g of the 84.00577 g, or 57.14% by mass. The derivation table below breaks the whole molecule down element by element.
The volume in the denominator is the volume of the finished solution, not the volume of water you started with. Dissolving 84.0058 g of a solid adds a little volume of its own, so a solution made up to the mark in a volumetric flask is at the molarity you calculated while the same solid stirred into a litre of water is slightly weaker. At dilute strengths the difference is negligible; at 1 M and above it is not.
Baking soda. It decomposes above about 50 degrees C in solution, so a stock solution does not keep the way a chloride does. At 84.00577 g/mol it is heavier than 6 of the 34 salts covered here, and that ranking matters more than it looks: ammonium nitrate has a molar mass of 80.043 g/mol, so a gram of it contains 4.95% more formula units than a gram of sodium bicarbonate. 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 1.6801 g of a nominal 84.00577 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 of sodium bicarbonate dissolved, in grams
V- The final volume of the solution, in millilitres
84.005769- The molar mass of sodium bicarbonate in g/mol, derived from its formula
c- The concentration in moles per litre
How it works, step by step
- Enter the mass of sodium bicarbonate you dissolved, in grams.
- Enter the final volume of the solution in millilitres.
- The mass is divided by 84.005769 g/mol and then by the volume in litres.
- The result is molarity in mol/L, with mmol/L, g/L and % w/v given alongside.
Worked examples
1 g of sodium bicarbonate made up to 100 mL
1 g is 0.0119039 mol. Divided by 0.1 L that is 0.119039 mol/L, or 119.04 mmol/L. The same solution is 10 g/L and 1% w/v — four ways of writing one strength.
5 g of sodium bicarbonate made up to 500 mL
5 g is 0.0595197 mol. Divided by 0.5 L that is 0.119039 mol/L, or 119.04 mmol/L. The same solution is 10 g/L and 1% w/v — four ways of writing one strength.
25 g of sodium bicarbonate made up to 1000 mL
25 g is 0.297599 mol. Divided by 1 L that is 0.297599 mol/L, or 297.6 mmol/L. The same solution is 25 g/L and 2.5% w/v — four ways of writing one strength.
How to read your score
Frequently asked questions
What is the molar mass of sodium bicarbonate (NaHCO3)?
It is 84.005769 g/mol. That is the sum of the standard atomic weights of every atom in the formula: 22.9898 (Na) + 1.008 (H) + 12.011 (C) + 3 × 15.999 (O). One mole of sodium bicarbonate therefore weighs 84.00577 g, and a gram of it is 11.904 mmol.
What percentage of sodium bicarbonate is oxygen?
57.14% by mass. Each formula unit contains 3 oxygen atoms contributing 47.997 g of the 84.00577 g total, so 100 g of sodium bicarbonate contains 57.14 g of oxygen and a kilogram contains 571.35 g of it.
How do I calculate the molarity of a sodium bicarbonate solution?
Divide the mass in grams by 84.005769 g/mol to get moles, then divide by the volume of solution in litres. Both divisions are in the calculator: enter grams and millilitres and it reports mol/L.
What is the molarity of 1 g of sodium bicarbonate in 100 mL?
0.119039 mol/L, or 119.04 mmol/L. The same gram in 250 mL gives 0.0476158 mol/L and in a litre 0.0119039 mol/L, since molarity falls in inverse proportion to the volume.
Is molarity per litre of water or per litre of solution?
Per litre of finished solution. That is why volumetric glassware is filled to a mark after the solid has dissolved rather than measured out first. Molality, which is per kilogram of solvent, is the quantity defined the other way and is not what this page computes.
How do mol/L, g/L and % w/v relate for sodium bicarbonate?
One mol/L of sodium bicarbonate is 84.00577 g/L, which is 8.4006% w/v. Going the other way, 1% w/v is 10 g/L and therefore 0.11904 mol/L. All three describe the same solution.
Molarity of sodium bicarbonate by mass and volume
| Element | Atoms | Atomic weight | Contribution (g/mol) | By mass |
|---|---|---|---|---|
| Oxygen (O) | 3 | 15.999 | 47.997 | 57.14% |
| Sodium (Na) | 1 | 22.98977 | 22.98977 | 27.37% |
| Carbon (C) | 1 | 12.011 | 12.011 | 14.3% |
| Hydrogen (H) | 1 | 1.008 | 1.008 | 1.2% |
| Total — one mole of sodium bicarbonate | 84.005769 | 100% |
Standard atomic weights, IUPAC 2021. The contribution column is atoms × atomic weight, and the total is the molar mass this page uses: 84.005769 g/mol.
| Solute | in 100 mL | in 250 mL | in 500 mL | in 1 L |
|---|---|---|---|---|
| 10 mg | 0.0011904 | 0.00047616 | 0.00023808 | 0.00011904 |
| 50 mg | 0.005952 | 0.0023808 | 0.0011904 | 0.0005952 |
| 100 mg | 0.011904 | 0.0047616 | 0.0023808 | 0.0011904 |
| 250 mg | 0.02976 | 0.011904 | 0.005952 | 0.002976 |
| 500 mg | 0.05952 | 0.023808 | 0.011904 | 0.005952 |
| 1 g | 0.11904 | 0.047616 | 0.023808 | 0.011904 |
| 2 g | 0.23808 | 0.095232 | 0.047616 | 0.023808 |
| 5 g | 0.5952 | 0.23808 | 0.11904 | 0.05952 |
| 10 g | 1.1904 | 0.47616 | 0.23808 | 0.11904 |
| 25 g | 2.976 | 1.1904 | 0.5952 | 0.2976 |
| 50 g | 5.952 | 2.3808 | 1.1904 | 0.5952 |
| 100 g | 11.904 | 4.7616 | 2.3808 | 1.1904 |
All figures in mol/L. Each is the mass divided by 84.005769 g/mol and then by the volume in litres, so the columns differ only by that volume.
| Compound | Formula | Molar mass (g/mol) | Millimoles in 1 g |
|---|---|---|---|
| Sodium hypochlorite | NaClO | 74.43877 | 13.434 |
| Potassium chloride | KCl | 74.5483 | 13.414 |
| Ammonium nitrate | NH4NO3 | 80.043 | 12.493 |
| Sodium bicarbonate (this page) | NaHCO3 | 84.00577 | 11.904 |
| Sodium nitrate | NaNO3 | 84.99377 | 11.766 |
| Magnesium chloride | MgCl2 | 95.205 | 10.504 |
| Calcium carbonate | CaCO3 | 100.086 | 9.9914 |
Ordered by molar mass. The last column is 1000/M, which is the number a weighed gram actually gives you.