Mole Fraction Calculator
Calculate the mole fractions of components in a mixture. Enter the number of moles of each component (up to 3) to find their mole fractions. Includes a verification check that all mole fractions sum to 1.
Mole fraction is a dimensionless way to express the concentration of a component in a mixture. It is defined as the ratio of moles of one component to the total moles of all components.
The Formula: χA = nA / (nA + nB + nC + ...)
Where χA (chi A) is the mole fraction of component A, nA is the moles of A, and the denominator is the total moles of all components. Mole fractions always sum to exactly 1 for a complete mixture.
Properties of Mole Fractions:
- Dimensionless (no units)
- Always between 0 and 1 (inclusive)
- Sum of all mole fractions in a mixture equals 1
- Temperature independent (unlike molarity)
- Used in Raoult's law: P_A = χA × P°A (vapor pressure)
- Used in Dalton's law: P_A = χA × P_total (partial pressure)
Conversions:
To convert between mole fraction and other concentration units, you typically need additional information such as molecular weights and densities. Mole fraction is related to molality by: χsolute = m × MW_solvent / (1000 + m × MW_solvent), where m is molality and MW_solvent is the molar mass of the solvent.