Mass fraction (chemistry)

In chemistry, the mass fraction is the ratio of one substance with mass to the mass of the total mixture , defined as

The sum of all the mass fractions is equal to 1:

Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (frequently, though erroneously, called percentage by weight, abbreviated wt%). It is one way of expressing the composition of a mixture in a dimensionless size; mole fraction (percentage by moles, mol%) and volume fraction (percentage by volume, vol%) are others.