 # Mole Fraction Formula

Mole fraction may be a unit of concentration in chemistry. A mole is really a variety of molecules, approximately 6 × 1023. A mole fraction is the ratio of molecules of 1 component during a mixture. For instance, if the mole fraction of methane in gas is 0.90, then this suggests that 90% of the molecules are methane. Since the quantity fractions are like mole fractions, the mixture is additionally 90%, by methane. During this article, we’ll discuss the mole fraction formula, its properties, and solved examples.

## Mole Fraction Formula

Mole fraction of every solute = number of moles of that solute/ the entire number of moles of all solutes and also the solvent.

It is just like the amount fraction. The lowercase Greek letter χ (chi) rather than a Roman x are the notations of mole fraction. For mixtures of gases, IUPAC recommends the letter y. It is a method of expressing the composition of a mix with a dimensionless quantity, the mass fraction (percentage by weight, wt%) and volume fraction (percentage by volume, vol%). Source: www.examfear.com

The advantage of the dimensionless mole fraction scale is that within the absence of reaction, the mole fraction of chemical substance k is independent of both temperature and pressure. The utilization of the mole fraction allows the calculation to be made for mixtures of gases.

## Properties of Mole Fraction

Mole fraction is employed very frequently within the construction of phase diagrams. it’s not temperature-dependent (such as molar concentration) and doesn’t require knowledge of the densities of the phases involved. A mix of known mole fraction is often prepared by weighing off the acceptable masses of the constituents.

The measure is symmetric: within the mole fractions, x = 0.1 and x = 0.9, the roles of ‘solvent’ and ‘solute’ are reversed. during a mixture of ideal gases, the mole fraction is often expressed because of the ratio of partial pressure to the entire pressure of the mixture. During a ternary mixture, one can express mole fractions of a component as functions of other components mole fraction and binary mole ratios.

Mole fraction is beneficial when two reactive components are mixed together because the ratio of the 2 components is understood if the mole fraction of every is understood. Multiplying mole fraction by 100 gives a mole percent, which describes an equivalent thing as mole fraction, just during a different form.

## Solved Examples for Mole Fraction Formula

Q] A Solution contains 30% by mass in carbon tet. Calculate the mole fraction of benzene using Mole Fraction Formula.

Solution: Total mass of the answer = 100 g

Mass of benzene = 30 g

Therefore, mass of carbon tet = (100 – 30)g

Benzene’s molar mass (C6H6) = (6 × 12 + 6 × 1) g mol – 1 = 78 g mol – 1

Hence, C6H6’s number of moles =30/78 mol = 0.3846 mol

Molar mass of carbon tet (CCl4) = 1 × 12 + 4 × 355 = 154 g mol – 1

∴ CCl4’s number of moles = 70/154 mol = 0.4545 mol

Mole fraction of C6H6 = [number of moles of C6H6 / number of moles of C6H6 + number of moles of (CCl4) ] X 100%

= 0.3846/ 0.3846+ 0.4545 = 0.458

Q] Determine the mole fraction of methanol CH3OH and water during a solution prepared by dissolving 5 g of alcohol in 50 g of H2O. M of H2O is eighteen and M of CH3OH is 32.

Solution: Moles of CH3OH = 5 / 32 = 0.1562 mole

Moles of H2O = 50 / 18 = 2.77 moles

Therefore, consistent with the equation

mole fraction of CH3OH = 0.1562 / 2.77 + 0.1562

= 0.0533

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