Molality Calculator
Works out molality from masses, without needing the volume.
Molality
— mol/kg
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Moles of solute — mol
Mass percent of solute — %
The formula
molality = moles of solute ÷ kilograms of solvent
Mass does not change with temperature, so neither does molality.
What to watch out for
Boiling point elevation and freezing point depression use molality for this reason.
Frequently Asked Questions
What is the difference between molarity and molality?
Molarity is per litre of solution. Molality is per kilogram of solvent. In dilute water solutions they are close.
What is the molality of 10 g of salt in 500 g of water?
0.3422 mol/kg, taking sodium chloride as 58.44 g/mol.