How this calculator works
Mole fraction counts a component amount relative to total mixture amount. A binary mixture has solvent fraction 1 - x. The molality conversion uses one kilogram of solvent, whose amount follows from its molar mass. This basis is appropriate only when the component definitions and dissociation convention are consistent.
Formula
x = n_solute/(n_solute + n_solvent); x = b M_solvent/(1 + b M_solvent), with M in kg/mol.
Worked example
1 mol solute and 3 mol solvent give x = 0.25 and 25 mol%. With b = 2 mol/kg and solvent M = 100 g/mol, x = 1/6.
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Frequently asked questions
Is mole fraction a percentage?
The fraction ranges from zero to one; multiply by 100 to express mol%.
Does an empty mixture have a mole fraction?
No. A positive total amount is required.
Is the solute limited to less than half the mixture?
No. The terms identify components; a mole fraction can exceed 0.5.