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Molality Calculator

Molality calculator

Calculate molality (mol/kg) from moles of solute and solvent mass.

InputsChemistry2 fieldsLive

Result

1.5 mol/kg

Uses m = n(solute) / mass(solvent in kg).

Live update

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Advanced options
Flow
  • Enter moles of dissolved solute.
  • Enter solvent mass in kilograms.
  • Read molality output in mol/kg.
Example

Worked example: 0.75 mol in 0.50 kg solvent

  1. 1 Molality relation is m = n / kg solvent.
  2. 2 Compute 0.75 / 0.50.
  3. 3 Result is 1.5 mol/kg.

Molality equals 1.5 mol/kg.

How
  1. Enter moles of dissolved solute.
  2. Enter solvent mass in kilograms.
  3. Read molality output in mol/kg.
Avoid
  • Using total solution mass instead of solvent mass.
  • Mixing grams with kilograms without conversion.
Checks

Best fit

Molality Calculator is built for calculate solution molality from moles of solute and solvent mass in kilograms. If Molality Calculator does not match the input scope, compare the answer with a second method.

Input check

Match the entered values to this rule before copying the answer: m = n(solute) / mass(solvent in kg).

Sanity check

For Molality Calculator, use the worked example as a quick benchmark: Molality equals 1.5 mol/kg. If the molality calculator answer is far away, check whether an input, unit, or mode changed.

Before copying

Review this common issue first: using total solution mass instead of solvent mass.

Ref only. Verify values. Follow lab safety.

FAQ
How is molality different from molarity?

Molality uses kg of solvent, while molarity uses liters of solution.

Why is molality useful?

It is less sensitive to temperature because mass is temperature-stable.

Can molality be zero?

Yes, when moles of solute are zero.

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