Mole Fraction Calculator
Calculate mole fraction (X) for any component in a mixture. Enter moles for multiple components to find their mole fractions and percentages.
What is mole fraction?
Mole fraction (X) is the ratio of the number of moles of a component to the total number of moles in a mixture. It is a dimensionless quantity, and the sum of all mole fractions in a mixture equals 1. For example, if a mixture has 2 moles of A and 3 moles of B, X_A = 2/5 = 0.4 and X_B = 3/5 = 0.6.
How does mole fraction differ from molarity?
Mole fraction (X) depends only on the number of moles and is temperature-independent. Molarity (M) depends on volume of solution, which changes with temperature. Mole fraction is preferred for thermodynamic calculations while molarity is more common in laboratory settings.
Can mole fraction be greater than 1?
No, mole fraction is always between 0 and 1. A mole fraction of 1 means the component is pure (100%), while 0 means the component is absent. Since all mole fractions in a mixture sum to 1, no individual value can exceed 1.
How do I convert mole fraction to mass percent?
To convert mole fraction to mass percent, multiply each mole fraction by the molar mass of that component to get mass contribution, then divide by total mass. Mass% of A = (X_A × M_A) / Σ(X_i × M_i) × 100.
What is the relationship between mole fraction and partial pressure?
For ideal gases, the partial pressure of a component equals its mole fraction times total pressure (Dalton's Law): P_A = X_A × P_total. This is useful for gas mixtures and calculating partial pressures in chemical reactions.
How is mole fraction used in Raoult's Law?
Raoult's Law states that the partial vapor pressure of a component equals its mole fraction in the liquid times its pure component vapor pressure: P_A = X_A × P°_A. This is fundamental to understanding vapor-liquid equilibrium in solutions.