Molality Calculator

m = moles solute / kg solvent. Used in colligative-property calculations (boiling-point elevation, freezing-point depression).

Inputs

Result

Molality
0.5000 m (mol/kg)
0.5 mol / 1 kg solvent.
  • Moles solute0.5
  • Kg solvent1
  • Molality (m)0.5000 mol/kg

Step-by-step

  1. m = n / kg = 0.5 / 1 = 0.5000 mol/kg.

How to use this calculator

  • Enter moles of solute and kilograms of solvent.
  • Read molality.

About this calculator

Molality is moles of solute per kilogram of solvent (note: solvent only, not solution). Unlike molarity, molality doesn't change with temperature because mass doesn't change with temperature. Used in colligative properties: ΔT_b = K_b × m, ΔT_f = K_f × m.

Frequently asked

Molality uses solvent mass, molarity uses solution volume. Molality is constant with temperature; molarity isn't.

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