# How to Find the Mole Fraction

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The mole fraction of a substance in a mixture is the amount of the substance in the given total amount of the mixture. Scientists usually calculate the mole fraction in terms of moles of the substance. The mole fraction is also a way of expressing solute concentration. It expresses the ratio of moles of a compound to the total moles of the mixture.

Calculate the moles of the solute by the formula: moles of solute = mass of the solute / molecular mass of the solute compound.

Calculate the moles of the solvent by the formula: moles of solvent = mass of the solvent / molecular mass of the solvent compound.

Calculate the mole fraction of the solute by the formula: mole fraction of the solute = moles of the solute / (moles of the solute + moles of the solvent).

Calculate the mole fraction of the solvent by the formula: mole fraction of the solvent = moles of the solvent/(moles of the solute + moles of the solvent).