Ideal-solution vapour pressures and mixture composition
For an ideal liquid solution in equilibrium with an ideal vapour, Raoult's law gives each component's partial pressure as its liquid mole fraction times its pure-liquid vapour pressure at the same temperature.
Key knowledge
For an ideal liquid solution in equilibrium with an ideal vapour, Raoult's law gives each component's partial pressure as its liquid mole fraction times its pure-liquid vapour pressure at the same temperature. Nonideal liquid interactions require activity corrections; the total pressure is the sum of partial pressures.
Values and equations
pᵢ = xᵢpᵢ*; p = ∑ᵢpᵢ
- pᵢ
- component vapour partial pressure Pa
- xᵢ
- liquid mole fraction 1
- pᵢ*
- pure-component vapour pressure at the same T Pa
- p
- total vapour pressure Pa
Conditions and scope
- Use matching temperatures and an appropriate liquid–vapour equilibrium model.
- Raoult behaviour is an ideal-mixture approximation; dilute solutes can require a Henry-law standard state rather than this pure-component convention.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected Raoult partial-pressure and total-pressure relations; qualifications exclude universal ideality.
2026-10-10 · Independent AI editorial review: All 94 actual compact claims, hypotheses, equation/variable/unit tables and 176 origin semantic links independently read. All exact author source-binding rows and disclosed extents assessed; targeted original bodies or specifically identified indexed primary passages rechecked below. All retained chemistry compact records read for combined breadth. Independent AI editorial content and practical common-core inventory review; no human specialist, degree/laboratory proficiency, whole-textbook certification or experimental replication. Receipt: chemistry-independent-content-inventory-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-chem-ideal-mixtures
- Revision
- core.1
- Structured reference record
- University core expansion