Molar MassMolar mass of sodium hydrogencarbonate (NaHCO3)
The molar mass of sodium hydrogencarbonate, NaHCO3, is 84.01 g/mol. One mole of it, which is 6.022 × 1023 formula units, has a mass of 84.01 grams.
84.01 g/mol
22.990 + 1.0080 + 12.011 + 3 × 15.999 = 84.006 · 6 atoms in the formula · also called sodium bicarbonate, baking soda
About sodium hydrogencarbonate
Sodium hydrogencarbonate is baking soda. On heating, or with an acid, it gives off carbon dioxide, which makes cakes rise. It is also a mild antacid and is used in some fire extinguishers.
Other names: sodium bicarbonate, baking soda.
The working
The formula NaHCO3 has 1 sodium atom, 1 hydrogen atom, 1 carbon atom and 3 oxygen atoms, 6 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 | 27.37% |
| Hydrogen (H) | 1 | 1.0080 | 1.008 | 1.20% |
| Carbon (C) | 1 | 12.011 | 12.011 | 14.30% |
| Oxygen (O) | 3 | 15.999 | 47.997 | 57.14% |
22.990 + 1.0080 + 12.011 + 3 × 15.999 = 84.006 g/mol
With the rounded atomic masses used in many school books (Na = 23, H = 1, C = 12, O = 16) the answer is 84 g/mol. The difference from 84.01 is too small to matter in most school sums.
Percentage composition
By mass, NaHCO3 is 27.37% sodium, 1.20% hydrogen, 14.30% carbon and 57.14% oxygen. The largest share comes from oxygen. In a 100 g sample there are 27.4 g of sodium, 1.2 g of hydrogen, 14.3 g of carbon and 57.1 g of oxygen.
Worked examples
Grams to moles. How many moles are in 5 g of NaHCO3? Divide the mass by the molar mass: 5 ÷ 84.01 = 0.05952 mol.
Moles to grams. What is the mass of 0.25 mol of NaHCO3? Multiply: 0.25 × 84.01 = 21 g.
Counting particles. 5 g contains 0.05952 mol × 6.022 × 1023 = 3.584 × 1022 formula units.
Making a solution. A 0.1 mol/L solution contains 0.1 × 84.01 = 8.401 g of NaHCO3 in each litre. For 250 mL, weigh 2.1 g and make it up to the mark with water.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 8.401 g |
| 0.5 mol | 42 g |
| 1 mol | 84.01 g |
| 2 mol | 168 g |
| 5 mol | 420 g |
| Mass | Moles |
|---|---|
| 1 g | 0.0119 mol |
| 10 g | 0.119 mol |
| 100 g | 1.19 mol |
| 1 kg | 11.9 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of NaHCO3?
The molar mass of sodium hydrogencarbonate (NaHCO3) is 84.01 g/mol, or 84.006 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of NaHCO3?
100 ÷ 84.01 = 1.19 mol.
What is the mass of one formula unit of NaHCO3?
Divide the molar mass by the Avogadro constant: 84.01 ÷ 6.022 × 1023 = 1.395 × 10-22 g.
What is the percentage of oxygen in NaHCO3?
Oxygen makes up 57.14% of the mass of NaHCO3: 3 × 15.999 ÷ 84.006 × 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.