NaCl Molar Mass
Sodium chloride
The molar mass of NaCl (sodium chloride) is approximately 58.44 g/mol. Each formula unit combines one sodium atom and one chlorine atom, so the exact sum is 22.99 + 35.45 = 58.44 g/mol — about 39.34% sodium and 60.66% chlorine by mass. Because NaCl is an ionic compound, this same number is properly called the formula mass.
Molar mass of NaCl
58.44 g/mol
| Formula | NaCl |
|---|---|
| Molar Mass | 58.44 g/mol |
| Formula Mass | ≈ 58.44 u |
| Sodium Atoms | 1 |
| Chlorine Atoms | 1 |
| Ion Ratio | 1 : 1 |
| Atoms per Formula Unit | 2 |
Good to know
NaCl is an ionic compound: a crystal lattice of Na⁺ and Cl⁻ ions with no discrete molecules. That is why chemists quote a formula mass per formula unit rather than a molecular mass.
How to Calculate the Molar Mass of NaCl
The sodium chloride molar mass is the sum of one sodium atomic weight and one chlorine atomic weight. The IUPAC standard atomic weights give exactly 58.44 g/mol — a value that also goes by "formula mass of sodium chloride", because NaCl is an ionic compound counted in formula units rather than discrete molecules.
NaCl
- Sodium: 1 × 22.99 = 22.99
- Chlorine: 1 × 35.45 = 35.45
22.99 + 35.45 = 58.44 g/mol
≈ 58.44 g/mol
Step 1 Read the chemical formula
NaCl contains 1 sodium atom and 1 chlorine atom. Subscripts count atoms, and a symbol without a subscript counts one.
Step 2 Find the atomic masses
Look up each element's IUPAC standard atomic weight on the periodic table: Na = 22.99 and Cl = 35.45. Most atomic weights are not whole numbers — each one averages an element's naturally occurring isotopes.
Step 3 Multiply by the atom counts
Each element contributes its atomic weight once per atom: Na: 1 × 22.99 = 22.99; Cl: 1 × 35.45 = 35.45.
Step 4 Add the contributions
22.99 + 35.45 = 58.44 g/mol. The IUPAC total is 58.44 g/mol. One mole of NaCl — 6.022 × 10²³ formula units, 2 atoms each — has exactly this mass in grams.
Elemental Composition of NaCl
Each element's share of the total mass of one mole of NaCl. One mole — about 58.44 g — contains 22.99 g of sodium and 35.45 g of chlorine, and every sample scales by the same ratio. Stated as percent composition, NaCl is 39.34% sodium and 60.66% chlorine by mass.
| Element | Atoms | Atomic Weight | Mass Contribution | Mass % |
|---|---|---|---|---|
| Sodium (Na) | 1 | 22.99 | 22.99 | 39.34% |
| Chlorine (Cl) | 1 | 35.45 | 35.45 | 60.66% |
| Total | 2 | 58.44 | 100% |
What Is the Formula Mass of NaCl?
The formula mass of NaCl is approximately 58.44 u per formula unit — numerically the same number as the molar mass, 58.44 g/mol, because one mole of formula units weighs as many grams as one formula unit weighs in unified atomic mass units. A formula unit is the smallest electrically neutral bundle of an ionic compound: one Na⁺ ion paired with one Cl⁻ ion in a 1 : 1 ratio. Solid sodium chloride is a crystal lattice in which every Na⁺ is surrounded by Cl⁻ neighbors and the other way around, so there is no such thing as an isolated "NaCl molecule" — the formula unit is the counting unit that plays the molecule's role.
You will still see "molecular weight of NaCl" in search results and homework questions. It is used informally, and it always expects the number 58.44 — but the more precise terms are formula mass and formula weight, which describe exactly what NaCl has: a mass per formula unit. "Molecular mass" is best reserved for compounds that really do form discrete molecules, such as CO₂ or H₂O. If a reference table lists 58.443 instead, it uses the older chlorine atomic weight of 35.453; the current IUPAC table (Cl = 35.45) gives 58.44, and the difference never matters for classroom work.
| Molar mass | 58.44 g/mol — the mass of one mole of NaCl formula units |
|---|---|
| Formula mass | ≈ 58.44 u (Da) — the mass of one single NaCl formula unit |
What Is the Chemical Formula for Sodium Chloride?
The chemical formula for sodium chloride is NaCl. Table salt is built from ions, not neutral atoms: each sodium atom transfers one electron to a chlorine atom, forming a Na⁺ ion and a Cl⁻ ion. The charges balance in a 1 : 1 ratio — the +1 of each sodium ion exactly cancels the −1 of each chloride ion — so the compound is electrically neutral overall and written with no subscripts at all.
Ionic formulas report the simplest whole-number ratio of ions — the formula unit — rather than a count of atoms bonded into a molecule. That ratio never varies: any crystal of sodium chloride, whatever its size, contains equal numbers of Na⁺ and Cl⁻ ions, which is why the formula is NaCl and not Na₂Cl₂ or any other multiple. In short, the sodium chloride formula is NaCl — one Na⁺ for every Cl⁻, charge-balanced and electrically neutral.
How Many Grams Are in One Mole of NaCl?
One mole of NaCl has a mass of approximately 58.44 grams. That is the whole conversion — the molar mass is the conversion factor between moles and grams. 1 mol × 58.44 g/mol = 58.44 g, and 2 mol = 2 × 58.44 = 116.88 g. Going the other way, divide by the same factor: 5.844 g of NaCl is 5.844 ÷ 58.44 = 0.1 mol. Type an amount below to convert either way; the calculation uses 58.44 g/mol.
1 mol of NaCl has a mass of 58.44 g
Need a full reaction calculation? Open the Stoichiometry Calculator →
NaCl Molar Mass Units and Conversions
Molar mass is normally quoted in grams per mole (g/mol), because lab-scale amounts are measured in grams and moles. The coherent SI unit is the kilogram per mole: 58.44 g/mol = 0.05844 kg/mol. Per formula unit, the same number appears in unified atomic mass units — one NaCl formula unit has a formula mass of about 58.44 u. The number never changes; only the unit — and the amount of NaCl it describes — does.
NaCl molar mass in every unit
- grams per mole: 58.44 g/mol
- milligrams per mole: 58,440 mg/mol
- kilograms per mole: 0.05844 kg/mol
- per formula unit: ≈ 58.44 u
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Frequently Asked Questions
What is the molar mass of NaCl?
Approximately 58.44 g/mol. Using IUPAC standard atomic weights, the sum is 1 × 22.99 (sodium) + 1 × 35.45 (chlorine) = 58.44 g/mol. Because NaCl is an ionic compound, the same number is also called the formula mass of sodium chloride.
How do you calculate the molar mass of NaCl?
Add the atomic mass of one sodium atom to the atomic mass of one chlorine atom: 22.99 + 35.45 = 58.44 g/mol. In general: count each element in the formula, multiply by its atomic weight, and add the contributions — exactly what the worked example above shows.
What is the formula mass of NaCl?
Approximately 58.44 u per formula unit. One formula unit is one Na⁺ ion paired with one Cl⁻ ion in a 1 : 1 ratio; numerically, formula mass in u and molar mass in g/mol are the same number.
What is the chemical formula for sodium chloride?
NaCl. Each Na⁺ ion balances one Cl⁻ ion, so the +1 and −1 charges cancel in a 1 : 1 ratio and the formula needs no subscripts.
How many grams are in 1 mole of NaCl?
About 58.44 grams. One mole contains 6.022 × 10²³ formula units, and the molar mass converts that amount directly to mass: 1 mol × 58.44 g/mol = 58.44 g. Two moles would weigh twice as much: 116.88 g.
Does NaCl have a molecular mass?
Strictly speaking, no. NaCl is an ionic solid — a lattice of Na⁺ and Cl⁻ ions with no discrete NaCl molecules — so the precise terms are formula mass or formula weight: about 58.44 u per formula unit. "Molecular weight of NaCl" is still used informally, and it always refers to the same number, 58.44.
What is the molar mass of NaCl to 3 decimal places?
58.440 g/mol — which is just 58.44 written to three decimals. The current IUPAC atomic weights are published to two decimal places (Na 22.99, Cl 35.45), so a third decimal adds no precision. Tables that use the older chlorine value of 35.453 print 58.443 g/mol instead. For homework and labs, 58.44 g/mol is the expected answer.