Molar Mass of Fe2(SO4)3 (Ferric Sulfate)

Molar Mass Calculator

What is the molar mass of Fe₂(SO₄)₃?

Answer

M(Fe₂(SO₄)₃) ≈

399.86 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.

Fe₂(SO₄)₃ = 2 Fe + 3 × (S + 4 O) → Fe 2, S 3, O 12

Contribution of each element
Element	Atoms, n	Atomic weight, A	n × A, g/mol Mass fraction, w	Mass fraction, w
Feiron	2	55.845	111.690 w ≈ 27.93%	≈ 27.93%
Ssulfur	3	32.06	96.18 w ≈ 24.05%	≈ 24.05%
Ooxygen	12	15.999	191.988 w ≈ 48.01%	≈ 48.01%
Σ = 399.858 ≈ 399.86 g/mol w = 100%				100%

Each fraction is rounded on its own, so the printed ones add up to 99.99%; unrounded, they make exactly 100%.

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

Mass fractions of the elements

O 48.01%

Fe 27.93%S 24.05%

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Molar masses of substances nearby

Formula	M, g/mol
Cr₂(SO₄)₃ (chromium(III) sulfate)	392.16
CHI₃ (iodoform)	393.72
C₁₂H₁₉Cl₃O₈ (sucralose)	397.63
Fe₂(SO₄)₃ (ferric sulfate)	399.86
AlI₃ (aluminum iodide)	407.68
C₁₂H₂₂CaO₁₄ (calcium gluconate)	430.372
HgI₂ (mercury(II) iodide)	454.39

FAQ

What is the molar mass of Fe2(SO4)3?

M(Fe₂(SO₄)₃) ≈ 399.86 g/mol

How to calculate the molar mass of Fe₂(SO₄)₃?

Add up the atomic weights of all the atoms in the formula: 2 × 55.845 + 3 × 32.06 + 12 × 15.999 = 399.858 ≈ 399.86 g/mol.

How many grams are in 2 moles of Fe₂(SO₄)₃?

m = n × M = 2 mol × 399.86 g/mol = 799.72 g.

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