Mole fraction (X)

Definition

Mole fraction (X) is a dimensionless quantity that represents the ratio of moles of a component to the total moles in a mixture. It is used to express the concentration of each component in gaseous mixtures.

5 Must Know Facts For Your Next Test

1. Mole fraction can be calculated using $X_i = \frac{n_i}{n_{total}}$, where $n_i$ is the number of moles of component $i$ and $n_{total}$ is the total number of moles in the mixture.
2. The sum of all mole fractions in a mixture always equals 1, i.e., $\sum X_i = 1$.
3. Mole fractions are essential for calculating partial pressures in gas mixtures using Dalton's Law: $P_i = X_i \times P_{total}$.
4. Mole fraction is useful in stoichiometry for determining the proportions of reactants and products in gaseous reactions.
5. Mole fractions do not have units because they are ratios.

Related terms

Partial Pressure:

The pressure exerted by an individual gas in a mixture as if it were alone in the container.

Dalton's Law:

A law stating that the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of each individual component.

Stoichiometry:

The calculation of reactants and products in chemical reactions based on balanced chemical equations.