Mole fraction (x_i = n_i / Σ n_j)
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x_i = n_i / Σ n_j
What each symbol means
| Symbol | What it stands for |
|---|---|
| n_i | Amount of substance of component i (mol) |
| x_i | Mole fraction of component i (dimensionless, 0 to 1) |
| Σ n_j | Total moles of all components in the mixture (mol) |
When to use this
Defined for any mixture; x₁ + x₂ + … = 1. Used in Raoult’s law, partial pressures, and colligative-property derivations.