What Is a Mole Fraction?

A mole fraction is equal to the moles of one substance in a compound divided by the total moles in the compound. The symbol for mole fraction is the lower case Greek letter chi. Mole fractions are often calculated in chemistry to determine the number of moles in various compounds.

Mole fractions can also be used to determine the molar percentage of a compound. To find the molar percentage from the mole fraction, simply multiply the mole fraction by 100. Another name for mole fraction is amount fraction. The same general equation for mole fraction can be used to determine the fraction of molecules in a compound.