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Molarity calculator: mass for a concentration

The mass to weigh for a concentration and volume, or the concentration a mass gives, with units that convert and the formula weight cited.

Molarity and stocks

The mass to weigh for a concentration and volume, or the volume for the mass you actually weighed.

Convert units

This action changes the number and unit together, preserving the physical quantity. The unit menu above continues to assign a unit to the entered number.

Convert units

This action changes the number and unit together, preserving the physical quantity. The unit menu above continues to assign a unit to the entered number.

Compound on the sheet: imatinib mesylate

Example

imatinib mesylate

imatinib mesylatePick a reagent
More inputs: purity, weight from the vial

Answer

Weigh
5.897mg
Stock mass with salt form, hydrate and purity
Concentration
10 mM
Final volume
1 mL
Formula weightas typed
589.72 g/mol
Solvent
DMSO

Open in the bench sheetThe bench sheet carries these inputs and offers the other calculators.

Worked example

  • Imatinib mesylate, C30H35N7O4S, 589.72 g/mol by CIAAW 2021.
  • 10 mM in 1 mL: n = 0.010 mol/L × 0.001 L = 10 µmol; m = 10 µmol × 589.715 g/mol = 5.897 mg.
  • At 98 percent purity the mass is divided by 0.98: 6.018 mg.

Method

  • Stock mass with salt form, hydrate and purity. src/lib/dilution/stock.ts 1.0.0Checked against Python's exact rational arithmetic (fractions.Fraction) to nine significant figures on 31 fixtures (6 October 2026).
  • Formula weight from the molecular formula. Prohaska T et al. Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure Appl Chem 2022;94:573-600. doi:10.1515/pac-2019-0603; ciaaw.org, read 6 October 2026.Checked against a CIAAW 2021 sum in Python's decimal module, with the formula from RDKit 2026.03.6, exactly on 58 fixtures (6 October 2026).

Constants

  • ciaaw-2021: IUPAC CIAAW 2021 standard atomic weights, conventional values for interval elements

Limits

  • For research and education only, and not medical advice: the stock, dilution and buffer calculations here are not for dosing or clinical preparation.
  • Formula weights use the IUPAC 2021 conventional atomic weights, so a vendor label may differ in the third decimal; a weight typed from the vial or a certificate of analysis overrides every computed value.

Verification