Molar Mass of PCl3 (Phosphorus Trichloride)

Molar Mass Calculator

What is the molar mass of PCl₃?

Answer

M(PCl₃) ≈

137.32 g/mol

Atomic weights: IUPAC standard values (CIAAW, 2024); the sum is rounded to the decimal places of the least precise one — Cl: 35.45.

Contribution of each element
Element	Atoms, n	Atomic weight, A	n × A, g/mol Mass fraction, w	Mass fraction, w
Pphosphorus	1	30.974	30.974 w ≈ 22.56%	≈ 22.56%
Clchlorine	3	35.45	106.35 w ≈ 77.44%	≈ 77.44%
Σ = 137.324 ≈ 137.32 g/mol w = 100%				100%

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

Mass fractions of the elements

Cl 77.44%

P 22.56%

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Molar masses of substances nearby

Formula	M, g/mol
CaSO₄ (calcium sulfate)	136.13
ZnCl₂ (zinc chloride)	136.28
C₆H₇N₃O (isoniazid)	137.142
PCl₃ (phosphorus trichloride)	137.32
Ba (barium)	137.33
C₇H₆O₃ (salicylic acid)	138.122
K₂CO₃ (potassium carbonate)	138.204

FAQ

What is the molar mass of PCl3?

M(PCl₃) ≈ 137.32 g/mol

How to calculate the molar mass of PCl₃?

Add up the atomic weights of all the atoms in the formula: 30.974 + 3 × 35.45 = 137.324 ≈ 137.32 g/mol.

How many grams are in 2 moles of PCl₃?

m = n × M = 2 mol × 137.32 g/mol = 274.64 g.

See Also