Mole Fraction Calculator
Dimensionless ratios that always sum to one.
Work out Mole Fraction. Dimensionless ratios that always sum to one. Says where the approximation breaks.
Mole fraction of A
0.25
4 mol total
A mole fraction is dimensionless and the fractions always sum to exactly 1, which makes it the natural measure wherever a ratio of amounts matters rather than a concentration: Raoult's law, Dalton's law of partial pressures, and every phase diagram are all written in mole fractions rather than molarity.
How the Mole Fraction Calculator works
A mole fraction is dimensionless and the fractions always sum to exactly 1, which makes it the natural measure wherever a ratio of amounts matters rather than a concentration — Raoult's law, Dalton's law and every phase diagram are written in mole fractions.
Also known as: mole percent calculator · mole ratio calculator · how to calculate mole fraction · mole fraction formula
Frequently asked questions
How do I calculate mole fraction?
Divide a component's moles by the total moles of everything present. One mole in four total is a mole fraction of 0.25.
Why not just use molarity?
Because molarity depends on volume, which changes with temperature and on mixing. Mole fractions are pure ratios of amount, so they are unaffected.
What is mole percent?
Mole fraction times 100. A fraction of 0.25 is 25 mole percent.
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