Molality converter
Convert molality between mol/kg, g/kg of solvent and weight percent, for the solute you choose.
That's about the same as a one-molal standard. Dissolved in water, that lowers the freezing point by about 1.86 °C (twice that for salt).
What it means
How concentrated is that?
Weight percent and grams per kilogram use the solute chosen above. The freezing-point figure is for water and a solute that does not split into ions; salt roughly doubles it.
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Learn
Three things worth knowing
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1 mol/kg lowers water’s freezing point by 1.86 °C
For a solute that stays whole, like sugar or urea. Salt splits into two ions and lowers it about twice as far, which is why roads are salted.
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Why chemists weigh the solvent
A liter flask holds a slightly different amount at 20 °C and 30 °C. A kilogram of water is a kilogram at any temperature, so molality gives the same answer in any laboratory.
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Molal is not molar
A 1 molal solution has a kilogram of solvent; a 1 molar one has a liter of finished solution. In dilute water they almost agree; in syrup or brine they differ by a lot.
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Background
About molality
Molality counts moles of dissolved substance per kilogram of solvent, not per liter of solution. Weighing never changes with temperature, so a molality stays the same when the solution warms and expands, while a molarity drifts.
That is why it is the unit of freezing points, boiling points and osmotic pressure in careful chemistry.