Molar Mass of Na2SO3 (Sodium Sulfite)

Molar Mass Calculator

What is the molar mass of Na₂SO₃?

Answer

M(Na₂SO₃) ≈

126.04 g/mol

Atomic weights: IUPAC standard values (CIAAW, 2024); the sum is rounded to the decimal places of the least precise one — S: 32.06.

Contribution of each element
Element	Atoms, n	Atomic weight, A	n × A, g/mol Mass fraction, w	Mass fraction, w
Nasodium	2	22.990	45.980 w ≈ 36.48%	≈ 36.48%
Ssulfur	1	32.06	32.06 w ≈ 25.44%	≈ 25.44%
Ooxygen	3	15.999	47.997 w ≈ 38.08%	≈ 38.08%
Σ = 126.037 ≈ 126.04 g/mol w = 100%				100%

Atomic weights: CIAAW, Abridged Standard Atomic Weights (2024)

Mass fractions of the elements

O 38.08%Na 36.48%

S 25.44%

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Molar masses of substances nearby

Formula	M, g/mol
ZnCO₃ (zinc carbonate)	125.39
SrF₂ (strontium fluoride)	125.62
MnCl₂ (manganese(II) chloride)	125.84
Na₂SO₃ (sodium sulfite)	126.04
C₂H₆O₆	126.064
C₅H₆N₂O₂ (thymine)	126.115
FeCl₂ (ferrous chloride)	126.75

FAQ

What is the molar mass of Na2SO3?

M(Na₂SO₃) ≈ 126.04 g/mol

How to calculate the molar mass of Na₂SO₃?

Add up the atomic weights of all the atoms in the formula: 2 × 22.990 + 32.06 + 3 × 15.999 = 126.037 ≈ 126.04 g/mol.

How many grams are in 2 moles of Na₂SO₃?

m = n × M = 2 mol × 126.04 g/mol = 252.08 g.

See Also