Molar Mass of Sodium Bicarbonate (NaHCO₃)
Learn how chemists calculate the molar mass of Sodium Bicarbonate (NaHCO₃), with a clear formula breakdown, worked steps, and study notes · IUPAC name: Sodium hydrogen carbonate.
Quick answer
The molar mass of Sodium Bicarbonate (NaHCO₃) is
84.006g/mol
One mole of Sodium Bicarbonate therefore has a mass of 84.006 grams—the value you use for stoichiometry and laboratory preparation.
Reviewed for educational accuracy · Accuracy policy
- CAS Registry Number
- 144-55-8
- PubChem CID
- 516892
- SMILES
- C(=O)(O)[O-].[Na+]
Step-by-step calculation
Let's find the molar mass of Sodium Bicarbonate (NaHCO₃) together—step by step, as if you are seeing the formula for the first time.
Step 1 — Look at the chemical formula
The formula is NaHCO₃. Each letter stands for an element. The little number after a letter (the subscript) tells you how many atoms of that element are in one molecule or formula unit.
- 1 Sodium atom (Na)
- 1 Hydrogen atom (H)
- 1 Carbon atom (C)
- 3 Oxygen atoms (O)
Step 2 — Look up each atomic mass
Atomic mass comes from the periodic table. It is the average mass of one mole of atoms of that element, in grams per mole (g/mol). Think of it as the "price tag" for one mole of that element.
- Sodium (Na) = 22.990 g/mol
- Hydrogen (H) = 1.008 g/mol
- Carbon (C) = 12.011 g/mol
- Oxygen (O) = 15.999 g/mol
Step 3 — Multiply atoms × atomic mass
Why multiply? If one oxygen atom "costs" about 16 g/mol, then two oxygen atoms cost twice as much. Each element's contribution is: number of atoms × atomic mass.
- 1 × 22.990 = 22.990 g/mol (Sodium)
- 1 × 1.008 = 1.008 g/mol (Hydrogen)
- 1 × 12.011 = 12.011 g/mol (Carbon)
- 3 × 15.999 = 47.997 g/mol (Oxygen)
Step 4 — Add the contributions
Why add? The molar mass of the whole compound is simply the total mass of every atom in the formula. Add each element's contribution:
22.990 + 1.008 + 12.011 + 47.997 = 84.006 g/mol
Step 5 — Final answer
Molar mass of Sodium Bicarbonate = 84.006 g/mol
That means one mole of Sodium Bicarbonate (NaHCO₃) has a mass of about 84.01 grams.
Quick summary
Read the formula → count atoms → look up atomic masses → multiply → add → report g/mol. For NaHCO₃, the total is 84.006 g/mol.
Common beginner mistakes
- Confusing sodium bicarbonate (NaHCO₃, 84.01 g/mol) with sodium carbonate (Na₂CO₃, 105.99 g/mol) — they react differently and have different basicity.
- Assuming baking powder and baking soda are interchangeable in recipes without adjusting for baking powder's built-in acid and lower potency per gram.
- Treating NaHCO₃ decomposition as instantaneous at room temperature — meaningful CO₂ release from heat alone requires temperatures well above typical kitchen or room conditions.
Memory trick
Remember bicarbonate's amphoteric nature: HCO₃⁻ can either donate a proton (to a strong base) or accept one (from a strong acid).
Mini practice
Without looking above, list the atoms in NaHCO₃ and write one multiplication line for the heaviest element. Then check your work against Step 3.
Real-world example
If a recipe asks for 0.100 mol of Sodium Bicarbonate, mass needed = 0.100 × 84.006 = 8.401 g. That is how chemists turn a mole amount into a weighable sample.
Atomic contribution table
Each row shows how much mass one element contributes to the total for NaHCO₃.
| Element | Atoms | Atomic mass | Contribution | Mass % |
|---|---|---|---|---|
| Na | 1 | 22.990 | 22.990 g/mol | 27.4% |
| H | 1 | 1.008 | 1.008 g/mol | 1.2% |
| C | 1 | 12.011 | 12.011 g/mol | 14.3% |
| O | 3 | 15.999 | 47.997 g/mol | 57.1% |
| Total molar mass | 84.006 g/mol | 100% | ||
Mass contribution chart
Teal and blue circles alternate like positive and negative ions in a crystal lattice. Formula mass is the mass of one formula unit, not a single molecule.
Download study sheets
Save a printable summary, revision sheet, practice worksheet, or laboratory reference for Sodium Bicarbonate (NaHCO₃).
Practice this calculation
Without looking above, write the atom count for NaHCO₃, then compute the molar mass. Check your answer against 84.006 g/mol.
Next challenge: how many grams are in 0.250 mol of Sodium Bicarbonate? Multiply 0.250 × 84.006 to get 21.002 g.
Physical and chemical properties
Physical properties
| Appearance | White crystalline powder |
| Color | White |
| Odor | Odorless |
| State (STP) | Solid |
| Density | 2.20 g/cm³ |
| Melting point | Decomposes at ~50 °C (does not have a true melting point; breaks down before melting) |
| Boiling point | Decomposes before boiling |
| Solubility | 96 g/L water at 20 °C (moderately soluble, increases with temperature) |
| Crystal structure | Monoclinic |
Chemical properties
| Classification | Amphoteric bicarbonate salt |
| Family | Alkali metal bicarbonates |
| Acidity | Weakly acidic character (HCO₃⁻ can donate a proton, pKa₂ of carbonic acid = 10.3) |
| Basicity | Weakly basic in solution (pH ≈ 8.3), acting as a mild base toward strong acids |
| Polarity | Ionic |
| Oxidation states | Na: +1, H: +1, C: +4, O: −2 |
Applications
Industrial uses
- Fire suppression agent in Class B/C dry chemical extinguishers
- Flue gas treatment (neutralizing acidic SO₂/HCl emissions)
- Leather tanning and textile processing pH buffer
- Feed additive for livestock (rumen pH buffering in dairy cattle)
Laboratory uses
- Mild, safe acid-neutralizing agent for spill cleanup (e.g., small acid spills)
- CO₂ gas generation demonstrations with vinegar or other weak acids
- Buffer component in some biological and biochemical buffer systems
Used in some flue-gas desulfurization and acid-gas scrubbing systems; considered environmentally benign compared to many industrial neutralizing agents due to low toxicity.
Endogenous bicarbonate is a critical blood buffer maintaining physiological pH (~7.4) via the carbonic acid–bicarbonate buffer system; NaHCO₃ is used clinically to treat metabolic acidosis and as an antacid.
Preparation and production
Industrially, NaHCO₃ is produced via the Solvay process, in which CO₂ and ammonia are passed through concentrated brine, precipitating sodium bicarbonate: NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl. It also occurs naturally as the mineral nahcolite and can be mined directly from evaporite deposits.
Global production combines Solvay-process synthesis with natural mineral extraction (notably from the Green River Formation in the western United States), yielding several million tonnes annually for food, industrial, and pharmaceutical use.
Important reactions of Sodium Bicarbonate
NaHCO₃(s) + HCl(aq) → NaCl(aq) + H₂O(l) + CO₂(g)
- Reaction type
- Acid–bicarbonate
- Conditions
- Room temperature, aqueous
- Explanation
- Bicarbonate acts as a base, accepting a proton from the strong acid and decomposing to release CO₂ gas — the basis of antacid action and classic vinegar-baking soda demonstrations.
- Products
- Sodium chloride, water, carbon dioxide
- Why it matters
- Antacid neutralization, acid spill cleanup, classroom gas-evolution demonstrations
Related ideas: Gas evolution · Neutralization · Antacid chemistry
2 NaHCO₃(s) → Na₂CO₃(s) + H₂O(g) + CO₂(g)
- Reaction type
- Thermal decomposition
- Conditions
- Heat above ~80–100 °C
- Explanation
- Two bicarbonate ions combine and lose water and CO₂ to form sodium carbonate; this reaction underlies both baking soda's leavening action in the oven and part of the Solvay process chemistry.
- Products
- Sodium carbonate, water vapor, carbon dioxide
- Why it matters
- Baking (leavening), soda ash production, fire extinguisher agent decomposition
Related ideas: Thermal decomposition · Leavening chemistry · Industrial chemistry
NaHCO₃(aq) + NaOH(aq) → Na₂CO₃(aq) + H₂O(l)
- Reaction type
- Acid–base (bicarbonate as weak acid)
- Conditions
- Aqueous, room temperature
- Explanation
- In the presence of a strong base, bicarbonate instead acts as a weak acid, donating its remaining proton to form carbonate — demonstrating its amphoteric character.
- Products
- Sodium carbonate and water
- Why it matters
- Illustrates amphoteric behavior, relevant to water treatment pH adjustment
Related ideas: Amphoteric species · Acid–base theory · Bicarbonate/carbonate equilibrium
NaCl(aq) + NH₃(aq) + CO₂(g) + H₂O(l) → NaHCO₃(s) + NH₄Cl(aq)
- Reaction type
- Industrial precipitation (Solvay process)
- Conditions
- Concentrated brine, ammonia, CO₂ gas, moderate temperature
- Explanation
- Sodium bicarbonate precipitates from ammoniated brine saturated with carbon dioxide, the central step of the industrial Solvay process for soda ash and bicarbonate manufacture.
- Products
- Sodium bicarbonate (precipitate) and ammonium chloride
- Why it matters
- Industrial-scale sodium bicarbonate and sodium carbonate production
Related ideas: Industrial chemistry · Precipitation · Solvay process
History and discovery
Naturally occurring sodium bicarbonate-rich mineral deposits and soda lakes were used by ancient civilizations for cleaning and food preparation. The Solvay process, developed by Ernest Solvay in the 1860s, revolutionized industrial-scale sodium carbonate and bicarbonate production, largely displacing the earlier, more wasteful Leblanc process.
Naturally occurring soda deposits were used since antiquity; the modern industrial process for synthesizing sodium bicarbonate/carbonate was developed by Ernest Solvay in Belgium in the 1860s.
Interesting facts
- NaHCO₃'s classic use as a refrigerator deodorizer relies on its ability to buffer and neutralize a wide range of acidic and basic odor compounds, not just mask them.
- The molar mass 84.01 g/mol makes NaHCO₃ almost exactly midway between water (18.02) and sodium carbonate (105.99) in a simple numeric sense, though the chemistry is quite different.
- The classic baking-soda-and-vinegar 'volcano' demonstration releases CO₂ so quickly because the reaction of a strong-ish acid (acetic acid) with bicarbonate is essentially instantaneous at typical concentrations.
- Nahcolite, the natural mineral form of NaHCO₃, is mined at industrial scale from ancient lakebed evaporite deposits in Colorado's Piceance Basin.
Comparison with similar compounds
NaHCO₃ (84.01 g/mol, pH ≈ 8.3) is a mild amphoteric salt, while its relative sodium carbonate Na₂CO₃ (105.99 g/mol, pH ≈ 11.6) is a considerably stronger base, formed from NaHCO₃ by loss of water and CO₂ on heating.
Storage, handling, and safety
Store in a sealed, dry container, since NaHCO₃ can absorb moisture and odors from the air (a property also exploited when it is used as a refrigerator deodorizer). Keep away from strong acids in bulk storage to prevent unintended CO₂ release and pressure buildup.
Very low toxicity; generally recognized as safe for food use. Avoid inhaling fine powder in bulk industrial handling, and be aware that mixing with acids in closed containers can build CO₂ pressure.
Very low toxicity and widely used as a food and household product; primarily a mild irritant risk from dust, with essentially no significant hazard at typical use concentrations.
- Mild eye/respiratory irritation from concentrated dust
- CO₂ pressure buildup if mixed with acids in sealed containers
- High sodium content a concern for patients on sodium-restricted diets
Classification: GRAS (Generally Recognized as Safe) for food use; not classified as a hazardous substance in typical handling
Exam notes and student tips
Exam notes
- Molar mass NaHCO₃ = 22.99 + 1.008 + 12.01 + 3(16.00) = 84.01 g/mol.
- Thermal decomposition: 2 NaHCO₃(s) → Na₂CO₃(s) + H₂O(g) + CO₂(g) on heating.
- Acid reaction: NaHCO₃ + HCl → NaCl + H₂O + CO₂ — a 1:1 mole ratio releasing one mole of gas per mole of bicarbonate.
- Bicarbonate is amphoteric: it can donate a proton (acting as a weak acid toward strong bases) or accept one (acting as a weak base toward strong acids).
Student tips
- Remember bicarbonate's amphoteric nature: HCO₃⁻ can either donate a proton (to a strong base) or accept one (from a strong acid).
- Link the Solvay process equation directly to NaHCO₃'s industrial origin for exam recall.
- Use the vinegar-and-baking-soda reaction as a mental model for 1:1 mole ratio acid-carbonate stoichiometry.
Common mistakes
- Confusing sodium bicarbonate (NaHCO₃, 84.01 g/mol) with sodium carbonate (Na₂CO₃, 105.99 g/mol) — they react differently and have different basicity.
- Assuming baking powder and baking soda are interchangeable in recipes without adjusting for baking powder's built-in acid and lower potency per gram.
- Treating NaHCO₃ decomposition as instantaneous at room temperature — meaningful CO₂ release from heat alone requires temperatures well above typical kitchen or room conditions.
Misconceptions
- Baking soda is not simply a 'weaker' version of baking powder — they have different compositions and are not directly substitutable without recipe adjustment.
- NaHCO₃ does not neutralize all types of fires — dry chemical extinguishers using it are rated for Class B (flammable liquids) and C (electrical) fires, not typically Class A (ordinary combustibles) alone.
- Bicarbonate ion is not the same as carbonate ion — NaHCO₃ and Na₂CO₃ have distinctly different basicity and reactivity despite both containing a carbon-oxygen anion.
Practice questions
1. Calculate the molar mass of NaHCO₃.
Show answer
22.99 + 1.008 + 12.01 + 3(16.00) = 84.01 g/mol
2. How many moles of CO₂ are released when 168.0 g of NaHCO₃ reacts completely with excess acid?
Hint: NaHCO₃ + acid → salt + H₂O + CO₂ is a 1:1 mole ratio for a monoprotic acid.
Show answer
168.0 g ÷ 84.01 g/mol = 2.00 mol NaHCO₃; 1:1 ratio gives 2.00 mol CO₂
3. What mass of Na₂CO₃ forms from thermally decomposing 16.80 g of NaHCO₃?
Show answer
16.80 g ÷ 84.01 g/mol = 0.200 mol NaHCO₃; ratio 2 NaHCO₃ : 1 Na₂CO₃, so 0.100 mol Na₂CO₃ × 105.99 g/mol ≈ 10.6 g
4. Why can sodium bicarbonate act as both an acid and a base?
Show answer
The bicarbonate ion HCO₃⁻ still has one ionizable proton (making it a weak acid toward strong bases) but can also accept a proton to form carbonic acid/CO₂ + H₂O (making it a weak base toward strong acids) — this is amphoteric behavior.
Frequently asked questions about Sodium Bicarbonate
84.01 g/mol.
Chemistry of Sodium Bicarbonate
The sections above give the number you need for calculations. Here we look more closely at how Sodium Bicarbonate (NaHCO₃) behaves chemically—so the molar mass connects to real reactions, properties, and laboratory practice.
Sodium bicarbonate (NaHCO₃) has a molar mass of 84.01 g/mol (Na 22.99 + H 1.008 + C 12.01 + 3 × 16.00), a white crystalline salt built from Na⁺ cations and the bicarbonate (hydrogen carbonate) anion HCO₃⁻. It is amphoteric in behavior — the bicarbonate ion can act as either a weak acid or a weak base — which gives NaHCO₃ its gentle, mildly alkaline character (pH ≈ 8.3 in solution) and its versatility across cooking, cleaning, medicine, and industrial chemistry.
Best known as baking soda, NaHCO₃ is a chemical leavening agent: it reacts with an acidic ingredient (buttermilk, yogurt, lemon juice, or added cream of tartar) or decomposes on heating to release CO₂ gas, which forms bubbles that cause batters and dough to rise. As an antacid, the same bicarbonate ion neutralizes excess stomach acid (HCO₃⁻ + H⁺ → H₂O + CO₂), providing rapid but short-lived relief from heartburn. Its ability to smother flames by releasing CO₂ and forming a heat-absorbing residue also makes it effective on small grease and electrical fires, and it is the active ingredient in some dry chemical fire extinguishers (specifically for Class B/C fires).
NaHCO₃ is closely related to — but chemically distinct from — sodium carbonate (Na₂CO₃, "soda ash" or washing soda), a more strongly alkaline salt made by heating NaHCO₃ to drive off CO₂ and water: 2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂. This conversion, and the reverse (Na₂CO₃ can be converted back to NaHCO₃ by adding CO₂ and water), is central to the Solvay process for industrial soda ash manufacture.
NaHCO₃ contains one Na⁺ ion paired with one HCO₃⁻ (bicarbonate) ion. The bicarbonate ion retains one ionizable proton on the carbonate framework — CO₃²⁻ with one oxygen protonated — making it an intermediate species between fully protonated carbonic acid (H₂CO₃) and fully deprotonated carbonate (CO₃²⁻). This partial protonation is the source of its amphoteric acid-base behavior.
NaHCO₃ is amphoteric: it neutralizes strong acids (releasing CO₂) and can also react with strong bases to form carbonate (HCO₃⁻ + OH⁻ → CO₃²⁻ + H₂O). It decomposes thermally above ~50–100 °C to sodium carbonate, water, and CO₂, the basis of its leavening action in baking. In fire suppression, the same thermal decomposition releasing CO₂ helps smother flames by displacing oxygen, while the endothermic decomposition also absorbs heat from the fire.
Chemical Leavening in Baking
NaHCO₃ releases CO₂ either by reacting with an acidic ingredient (NaHCO₃ + acid → CO₂ + H₂O + salt) or by thermal decomposition above roughly 80 °C; the trapped gas bubbles expand within batter or dough, creating the light, aerated texture of baked goods — a reaction so central that recipes are carefully balanced between acid and base to avoid a metallic or soapy off-taste from unreacted bicarbonate.
Baking Soda vs. Baking Powder
Baking soda (pure NaHCO₃) needs an external acid to activate; baking powder is a premixed blend of NaHCO₃ with a dry acid (such as cream of tartar or sodium acid pyrophosphate) plus a starch filler, so it can leaven recipes that lack sufficient natural acidity on their own — a frequent point of confusion in cooking chemistry.
Antacid Action and Stomach Chemistry
As an over-the-counter antacid, NaHCO₃ rapidly neutralizes excess gastric HCl (NaHCO₃ + HCl → NaCl + H₂O + CO₂), providing fast symptomatic relief; the released CO₂ can cause belching, and the sodium load makes it less suitable than other antacids for patients managing sodium intake.
Fire Suppression Chemistry
In Class B/C dry chemical fire extinguishers, NaHCO₃ powder decomposes in the heat of a fire to release CO₂, which helps smother flames by displacing oxygen, while the endothermic decomposition absorbs heat — a dual physical and chemical firefighting mechanism distinct from water-based suppression.
NaHCO₃ vs. Na₂CO₃
Sodium bicarbonate (mild, pH ≈ 8.3) and sodium carbonate (strongly alkaline, pH ≈ 11.6) are related by a simple thermal decomposition (2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂) but behave very differently: washing soda (Na₂CO₃) is used for heavy-duty cleaning and water softening, while baking soda's gentler basicity suits food, personal care, and mild cleaning applications.
Recalculate any formula with the molar mass calculator, compare atoms on the periodic table, or browse more compounds in the salt library.
References and further reading
- NIST Chemistry WebBook: NaHCO₃ thermodynamic data
- PubChem CID 516892: Sodium bicarbonate identifiers and properties
- FDA Food Additive Status: GRAS status for sodium bicarbonate in food