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Mass ↔ amount of substance conversion

n = m / M

Calculate the amount of substance (n) from a mass and the molar mass, or the reverse, with n = m / M.

Known quantities
Solute mass (m)
Molar mass (M)
Amount of substance (n)

Awaiting the quantities required for the calculation.

Scientific dossier

What the tool computes, what it assumes, where it stops being valid, and where its data comes from.

Method & formulasn = m / M

n = m / M

m = n × M

The amount of substance and the mass of a given sample are linked by its molar mass.

m
· mass of the sample.
n
· amount of substance, in moles.
M
· molar mass of the compound, in g/mol.
Validity domainUse the molar mass of the compound actually weighed: a hydrated salt (for example CuSO₄·5H₂O) has a different molar mass from its anhydrous form.

Use the molar mass of the compound actually weighed: a hydrated salt (for example CuSO₄·5H₂O) has a different molar mass from its anhydrous form. This standalone converter covers only n = m / M; to relate n to a volume and a concentration (C = n / V), use the molarity calculator, which also includes this calculation as a secondary mode.

Example18.

18.015 g of water (M = 18.015 g/mol) corresponds to 1 mol of water (n = m / M = 18.015 / 18.015).